GEOPHYSICAL HAZARDS AND RISKS: PREDICTABILITY,
MITIGATION, AND WARNING SYSTEMS (IAPSO, IASPEI, IAVCEI,
IAHS, IAMAS, IAG, IAGA, IUGG TSUNAMI COMMISSION, ILP)
Location: Poynting Physics S02 LT
Location of Posters: Bridge Poynting/Watson
Friday 23 July AM
Presiding Chair: T BEER (CSIRO Atmospheric Research, Aspendale, Austrailia)
Concurrent Poster Session
HAZARD AND RISK ASSESSMENT, RISK MITIGATION AND
MANAGEMENT
JSP23/C/U5/P/01-A5 Invited 0830
ATMOSPHERIC HAZARDS ASSOCIATED WITH THE EL NINO/SOUTHERN OSCILLATION PHENOMENA: A SYNTHESIS
Madhav L KHANDEKAR (Consultant, Baird & Associates, Ottawa, Ontario, CANADA, L3R 7Z5)
The ENSO phenomenon – spreading of warm water from the equatorial central Pacific to the equatorial South American coast and associated global weather anomalies -- is now identified as the strongest signal in the global climate system after the annual cycle. The term El Nino refers to the spreading of anomalously warm water off the coast of Ecuador and Peru and associated weather anomalies over the west coasts of the Americas. The Southern Oscillation is the atmospheric counterpart of El Nino and refers to the slowly varying atmospheric pressure differential over the eastern and western regions of the tropical Pacific. The two phenomena together are now popularly known by the acronym ENSO (El Nino/Southern Oscillation).
The appearance of warm water off the coast of South America and associated changes in the regional weather patterns were known to Peruvian fishermen for over 400 years. The landmark papers of Jacob Bjerknes in the Nineteen Sixties provided a physical link between ENSO and weather anomalies over the entire equatorial Indo-Pacific basin. Several studies inspired by Bjerknes' landmark papers and reported in the last twenty-five years have documented a link between ENSO and global weather anomalies.
This paper provides an overview of global weather anomalies and associated atmospheric hazards in the context of the ENSO phenomena. The paper further presents several examples of atmospheric hazards associated with extreme weather events and their relationship to the various phases of ENSO. The importance of monitoring various phases of the ENSO phenomena through suitable atmospheric and oceanic indices will be discussed in the context of long-range weather forecasting.
JSP23/W/04-A5 0910
ENSO AND ‘ENSO-LIKE’ IMPACTS ON INTERANNUAL TO SECULAR TIME SCALES
Robert J. ALLAN (CSIRO Atmospheric Research, Aspendale, Victoria 3195, Australia,
email: rob.allan@dar.csiro.au); Ian N. Smith (CSIRO Atmospheric Research, Aspendale, Victoria 3195, Australia, email: ins@dar.csiro.au).
Efforts to improve our understanding of the various types of natural variability inherent in the global climate system have included a growing focus on the El Niño Southern Oscillation (ENSO) phenomenon and lower frequency ‘ENSO-like’ decadal to secular scale fluctuations. Signal detection analyses applied to global historical sea surface temperature and mean sea level pressure anomalies, reveal significant climatic signals operating on quasi-biennial, inter-annual, decadal multi-decadal and secular time scales. The ENSO signal is seen to consist of quasi-biennial (QB) and lower frequency (LF) components that interact to produce important modulations of the phenomenon. ‘Protracted’ El Niño and La Niña episodes are found to be a consequence of the ‘phasing’ of quasi-decadal and inter-decadal ‘ENSO-like’ signals with the QB and LF ENSO components. Further climatic modulations are provided by ‘ENSO-like’ phenomena operating on multi-decadal time scales. The secular trend, reflecting the observed global warming signal, reveals neutral to slightly ‘La Niña-like’ conditions in the Pacific sector. The impact of the above climatic signals can be seen in the patterns of correlation with global precipitation and mean surface land temperatures. Significant contributions to rainfall and land temperature variability are evident, not just in known ‘ENSO-sensitive’ regions. In addition, El Niño and La Niña episodes on inter-annual time scales can be both synchronous and asynchronous with ‘El Niño-like’ and ‘La Niña-like’ signals on various decadal to multi-decadal time scales, resulting in the range of fluctuations seen in many rainfall and temperature impacts over time.
JSP23/E/43-A5 0930
UNDERSTANDING MULTI-HAZARD RISK IN URBAN COMMUNITIES
Ken GRANGER (Australian Geological Survey Organisation, GPO Box 762, Brisbane, Queensland, 4001, Australia, Email: kgranger.agso@bom.gov.au)
The sciences that address geophysical hazards have traditionally focused on the study of hazard phenomena. Doing something about those hazards, and reducing the risks to the community that they pose, has tended to be left to the engineering profession or, in the extreme, to disaster managers. The past decade, however, has seen a paradigm shift, with increasing attention being paid to 'risk management' across many disciplines.
Developing a comprehensive understanding of the risks faced by an urban community is the first challenge to be met if appropriate risk reduction strategies and response options are to be implemented and their effectiveness monitored. This is not a simple task. Hazard phenomena are complex, if not chaotic, in their behaviour; whilst the communities on which they impact are equally complex. An understanding of the interaction between the various potential hazard phenomena, the elements at risk in the community (the people, buildings, lifelines, etc) and their respective levels of vulnerability to those impacts, is the essence of risk science.
The city of Cairns (population 125 000) in Far North Queensland, is a community with a 134-year history of severe tropical cyclone impacts, floods, landslides, (so far minor) earthquakes and technological accidents, is used to illustrate the quantitative risk analysis and scenario-based risk assessment methods and GIS-based decision support tools developed under the Australian Geological Survey Organisation's Cities Project.
JSP23/W/31-A5 0950
FLOOD EVENTS IN THE RHINE RIVER BASIN: GENESIS, INFLUENCES AND MITIGATION
Markus DISSE (German Federal Institute of Hydrology, P.O. Box 309, D-56003 Koblenz, Germany, Email: disse@bafg.de); Heinz Engel (German Federal Institute of Hydrology, P.O. Box 309, D-56003 Koblenz, Germany)
The catchment of the river Rhine can be distinguished in 4 main subcatchments: the alpine region with the river Aare as the main tributary and downstream the lower mountain regions of the tributaries Neckar, Main and Moselle. These four basins clearly generate different hydrographs. Due to the geographical circumstances, the average discharge maximum shifts from summer towards winter downstream the Rhine. However, spatial and temporal precipitation patterns have a strong influence on the individual flood. The particular genesis of recent and historical floods will be discussed. Besides the climatological causes a brief overview of the manmade alterations to the river system itself (Rhine and tributaries) and to the linked catchments are given and their effect will be indicated. However, up to now the influence of land surface and river training measures on flood conditions in the Rhine basin has not exactly been quantified. Therefore, the Dutch-German project LAHoR has been established within the framework of the EU-project IRMA (INTERREG II C Rhine Maas Activities). The results of this project may give efficient advice for the "Action Plan on Flood Defence" of the International Commission for the Protection of the Rhine (ICPR), which is briefly introduced. In this plan a multidisciplinary approach to mitigate floods is suggested that can yield to synergic effects between flood prevention, water management, regional planning, agriculture, forestry and ecological demands.
JSP23/E/37-A5 1010
THE SUVA EARTHQUAKE RISK MANAGEMENT SCENARIO PILOT PROJECT (SERMP) -MITIGATION OF EARTHQUAKE AND TSUNAMI RISKS FOR THE CITY OF SUVA, FIJI
Jack RYNN (Centre for Earthquake Research in Australia, PO Box 276, Indooroopilly, Brisbane, Queensland 4068, Australia, email: sally.brown@uq.net.au); Poasa Raveo (Department of Regional Development and Multi-Ethnic Affairs, Government of the Republic of Fiji, PO Box 2219, Government Buildings, Suva, Fiji); Atu Kaloumaira (South Pacific Disaster Reduction Management Office,
c/o UNDP, Private Mail Bag, Suva, Fiji, email: atu@sopac.com.org)
The 1953 Suva earthquake (ML 5.6) and associated tsunami is a stark reminder of the vulnerability of the City of Suva to such natural hazards. Through the UN IDNDR program, per the 1994 "Yokohama Statement", the Government of the Republic of Fiji took the challenge to counter mitigation strategies. SERMP was a co-operative effort of the Government, UNDP-UNDHA and international consultants. A specific methodology was developed to address definitive project components of hazard, vulnerability and risk assessments, mitigation measures, response planning, public awareness, policy support and dissemination of findings. Wide-ranging outcomes for both earthquake and tsunami, of risk assessments, loss estimations, disaster planning, risk management and tsunami warning, with 90 recommendations, were documented as an ""information resource:" These were implemented as "practical applications" in building codes, GIS, land use planning, disaster plans, training, emergency management and community education. A Sub-Regional Seminar and exercise "SUVEQ 97""were conducted. SERMP also demonstrated mitigation measures to decision makers in all Pacific Island Countries.
JSP23/W/19-A5 1050
THE AUSTRALIAN ENVIRONMENTAL RISK MANAGEMENT FRAMEWORK
Tom BEER (CSIRO Atmospheric Research, Aspendale, 3195, Australia, email:Tom.Beer@dar.csiro.au)
Environmental risk management deals with impacts on the environment, as well as with impacts on organisations that disturb the environment. Management options are based on a measure of the risk, which is obtained through an analysis of both the likelihood and the consequences of the impact. Many of the concepts, and much of the terminology, of environmental risk assessment have arisen from its use by the US EPA as an objective tool that provides information on which to base environmental decisions. A key step in the United States was to maintain a clear separation between risk treatment and risk assessment. Risk treatment is an activity undertaken by decision-makers and managers, whereas risk assessment is an activity undertaken by technicians. Many workers have argued that one cannot maintain such a clear distinction and a conference of the Australian Academy of Science developed an Environmental Risk Management framework. Australia has been reluctant to embrace the US-inspired clear distinction between risk treatment and risk assessment. Australia has, instead, combined risk assessment (envisaged as a combination of risk analysis and risk evaluation) and risk treatment within a generic risk management framework that has been incorporated into the Australian/New Zealand Standard on Risk Management, AS/NZS 4360. This presentation synthesises the Australian Risk Management and Environmental Risk Management frameworks.
JSP23/W/02-A5 1110
CAUSE-EFFECT MODELS OF LARGE LANDSLIDES
Ewald P. BRUECKL (Vienna University of Technology, Gusshausstrasse 27-29, A-1040 Vienna, Austria, email: ebrueckl@ luna.tuwien.ac.at)
Within the scope of IDNDR cause-effect models of large landslides are being developed to estimate potential danger. This work is based on structural exploration of the landslides mainly by seismic methods. Information about the status of deformation is got by comparison of the actual topography with a reconstruction of the original topography, GPS and SAR interferometry. Geological and geomorphological evidence, as well as relevant information from other geoscientific disciplines, is included. The Finite Element method is used to model the initial phase of a mass movement. Later on this modelling will be extended to the quasi-stationary creep phase and the transition from creeping to rapid sliding.
Three large landslides within the crystalline rocks of the Eastern Alps have been investigated since 1997. The largest one is the Koefels landslide with a total volume of 3.9 km3 and a potential energy release of 5_1016 Joule. Refraction and reflection multi-component seismic techniques were applied successfully to resolve structure and elastic parameters of the landslide masses. For the modelling of the initial phase of the landslides by the Finite Element method a strain softening behaviour of the rock mass has been assumed. The development of softened or fractured zones according to the structures obtained by the seismic measurement was simulated.
JSP23/L/04-A5 1130
PSEUDOSCIENCE U.N. DOCUMENT: GEOMAGNETIC FORECASTING OF EARTHQUAKES AND METEOROLOGICAL DISASTERS
Wallace H. CAMPBELL (World Data Center A for Solar-Terrestrial Physics, NGDC / NOAA, 325 Broadway, Boulder, CO 80303-3328, USA, e-mail: whc@ngdc.noaa.gov)
The United Nations recently published a "Manual on the Forecasting of Natural Disasters: Geomagnetic Methods" (1998) by Chinese and U.N. authors that stretches the imagination with prediction of earthquakes and Meteorological disasters. A careful reading of this document reveals an illusionary approach to the subject with no valid supporting evidence of prediction capability. The "mathematical" section simply copied well-known formulae that provided no scientific details of any physics connecting changes in geomagnetic recordings and subsequent localized disastrous earthquakes or meteorological events. The presented data indicated that 82.3 % of the recorded earthquakes did not correspond well to predictions. The authors ignored the recommendations and testing suggestions of a 1996 international London meeting, Assessment of Schemes for Earthquake Prediction. The manual provides clear and reliable evidence of the improper use of public funds for building hopes of disaster relief with projects totally lacking in scientific merit.
JSP23/W/26-A5 1150
25 SECONDS FOR BUCHAREST
Friedemann WENZEL, Mihnea C. Oncescu, Michael Baur and Frank Fiedrich (University of Karlsruhe, 76128 Karlsruhe, Germany, email: fwenzel@gpiwap1.physik.uni-karlsruhe.de); Constantin Ionescu (National Institute for Earth Physics, P.O. Box MG-2, 76900 Bucharest, Romania,
email: viorel@infp.ifa.ro)
The Romanian capital Bucharest faces a significant earthquake hazard with a 50% chance for an event in excess of 7.6 moment magnitude every 50 years. Within the last 60 years Romania experienced 4 strong Vrancea earthquakes: Nov. 10, 1940 (Mw = 7.7, 160 km deep); March 4, 1977 (Mw = 7.5, 100 km deep); Aug. 30, 1986 (Mw = 7.2, 140 km deep); May 30, 1990 (Mw = 6.9, 80 km deep). The 1977 event had catastrophic character with 35 high-rise buildings collapsed and 1500 causalities, the majority of them in Bucharest. A group of civil engineers and seismologists from the National Institute of Earth Physics (NIEP) in Romania and Karlsruhe University in Germany propose an Early Warning System (EWS) for the capital city of Bucharest. The group studied the seismological boundary conditions of an EWS for the Romanian capital of Bucharest. The earthquakes threatening the capital are intermediate deep events with magnitudes close to Mw = 8.0 at an almost fixed epicentral distance of about 150 km. The travel-time difference between the destructive S-wave arriving in Bucharest and the epicentral P-wave is always greater than 25 s, which represents the maximum possible warning time. Moreover source mechanisms are extremely stable for larger and smaller events so that a projection of the level of ground motion to be expected in Bucharest can be based on the amplitude of the epicentral P-wave rather than on cumbersome determination of magnitude and depth. This feature allows the design of a simple, robust and fast EWS. With 25 s, a system with the largest warning time after the Seismic Alarm System for Mexico City could be established. Even this small time window can provide opportunities to automatically trigger measures such as, shutdown computers; re-route electrical power; shutdown airport operations; shutdown manufacturing and high-energy facilities; stop trains; shutdown gas distribution; alert hospital operating rooms; open fire station doors; start emergency generators; stop elevators in a safe position; issue audio alarms; maintain safe-state in nuclear facilities. The value of an EWS can be judged on the basis of an application specific costs-benefit analysis, but simple considerations suggest that it will be cost-efficient.
JSP23/E/31-A5 1210
GLOBAL VOLCANIC SIMULATOR: ERUPTION FORECASTING AND URBAN PLANNING OFDENSELY POPULATED AREAS
Flavio DOBRAN (Global Volcanic and Environmental Systems Simulation, 32-50, 34 Street, Long Island City, New York 11106, Email: dobran@idt.net)
A Global Volcanic Simulator consists of physico-mathematical models of the volcano that are effectively implemented for solution on distributed or parallel computers. Such a simulator can be used to forecast future eruptions and for studying their effects on people and infrastructures for the purpose of mitigating eruption consequences. Current simulator for Vesuvius models magma reservoir volume, temperature, and pressure changes, variable rates of magma supply into the chamber, and varying elastic, plastic, and heat transfer characteristics of magma reservoir surroundings. Different types of magma ascent models allow for time-varying and non-isothermal simulations, including magma flow regime changes and melting of conduit walls. These models have been used to forecast that a plinian or subplinian eruption of Vesuvius will occur within the next 100 years and that the pyroclastic flows from column collapses can destroy the surrounding territory in several minutes. The simulator is also being employed to study the effects of different eruption scenarios on the territory and how this territory can be protected by engineering intervention measures. Computer simulations of possible eruptions of Vesuvius are also being utilised to sensitise the population of the area.
A useful simulator requires reliable geological and geophysical data of the volcano's internal structure, whereas the verification and validation of complex physical models on computers presents both computational and physical modeling challenges that are described in: Dobran, F., Theory of Structured Multiphase Mixtures, Springer Verlag, New York, 1991; Dobran F., Global Volcanic Simulation of Vesuvius, Giardini, Pisa, 1993; Dobran, F., Etna: Magma and Lava Flow Modeling and Volcanic System Definition Aimed at Hazard Assessment, Topografia Massaroa Offset, 1995.
Friday 23 July PM
Presiding Chair: Prof. Dr.F Wenzel (Universitaet Fridericiana Karlesrune, Germany)
JSP23/E/20-A5 1400
EXTRATROPICAL EVOLUTION OF TROPICAL CYCLONES AS AN UNEXPLORED HAZARD IN MIDDLE AND HIGHER LATITUDES
Jenni L. EVANS (Department of Meteorology The Pennsylvania State University University Park PA 16802, USA.)
A recent climatology of extreme rainfall incidence in the northeast United States (including New England) reveals that the passage of a tropical cyclone is the cause of major rainfall events every 2-3 years over most of this region. Locations such as Boston and Cape Cod are particularly susceptible, with individual events resulting in twice their monthly rainfall due to a single tropical cyclone passage every 5-6 years. At the time that these tropical cyclones are delivering such copious rainfalls, they are typically undergoing complex structural changes that are poorly understood.
The lifecycle of the tropical cyclone through to a hybrid or truly extratropical cyclone and the associated rainfall evolution will be elucidated here and a theoretical underpinning provided.
JSP23/C/U5/E/14-A5 1420
NATURAL DISASTERS: A POSTGRADUATE PROGRAM AT UNIVERSITY OF KARLSRUHE
Jens MEHLHORN, Frank Fiedrich and Fritz Gehbauer (Institute for Construction Equipment and Construction Management, University of Karlsruhe, Am Fasanengarten, 76126 Karlsruhe, Germany, email: mehlhorn@imbdec1.bau-verm.uni-karlsruhe.de)
According to the United Nations the annual financial loss as a result of natural disasters increased from 50 billion to 360 billion US-dollar during the last 35 years. This fact presents a tremendous challenge to politics, society, and the scientific community. Disaster related research has to be increased. On the basis of fundamental research new knowledge will be created and used to develop practical tools for hazard and risk assessment. More effective measures for reducing this risk can be taken and the performance of emergency response can be improved. These steps towards a better understanding of disaster causes and effects and improved disaster management have been demanded since the UN-decade IDNDR (International Decade for Natural Disaster Reduction) started in 1991. The Postgraduate Program Natural Disasters has to be seen in this context. A total of 15 institutes of different fields work together in this project involving five departments of the university.
The research projects include topics like Modelling of Hazard and Risk, Development of Disaster Scenarios, Mitigation Aspects and Economic Consequences of Natural Disasters. During the first period the activities concentrate on floods, earthquakes, strong rainfalls and land-slides. Natural sciences like physics, hydrology, meteorology and geosciences give a contribution to the basic understanding of the disaster process. Mathematics and computer sciences are used for complex models, for modelling fuzzy and imprecise information and for forecasts. With the help of economics the risk can be quantified and evaluated. In addition the institutes dealing with engineering aspects develop measures and tools for risk mitigation.
JSP23/C/U5/W/13-A5 1440
WORLD MAP OF NATURAL HAZARDS – A DEPICTION OF THE GLOBAL DISTRIBUTION OF SIGNIFICANT HAZARDS AND THEIR INTENSITY
G. Berz, S. Ehrlicher, T. Loster, E. Rauch, A. Siebert, J. Schimetschek, J. SCHMIEDER, A. Smolka and A. Wirtz (Munich Re, Geoscience Research Group, D-80791 Munich, Germany, Tel. 0049-89-3891-5291, Fax: 0049-89-3891-5696, E-mail: info@munichre.com)
For over 25 years now Munich Re's Geoscience Research Group has been looking at natural hazards throughout the world. Twenty years ago it summarised the overall results of its work in the first edition of the World Map of Natural Hazards. The map represents a unique source of information for numerous insurance companies, engineering offices, planning authorities, geoscientists, schools and interested lay people world-wide. For the recently released third edition all the basic data was for the first time captured and analysed using Munich Re's geographical information system (GIS). The resulting maps were created using digital cartography. Four auxiliary maps have supplemented the new edition. The earthquake and windstorm zones contained in the previous editions have been updated, refined and augmented. There are also details of other significant natural hazards like severe rainfall, storm surges, hail and lightning. A particularly interesting innovation is the auxiliary map on climate change. It deals on the one hand with the effects of El Niño, which generated so much interest and concern internationally in 1997/98 and was responsible for numerous natural catastrophes. Even more important are the effects that are to be expected from the emerging phenomenon of global warming, which will be accompanied by more frequent and more dramatic natural catastrophes in many parts of the world and will lead to a distinct long-term deterioration in the risk situation. The accompanying publication provides a detailed catalogue of historic natural catastrophes that have occurred in countries all over the world, grouped by continent and listed chronologically with additional information on the number of deaths and the economic losses.
JSP23/C/U5/W/11-A5 1500
ASSESSMENT OF HYDROLOGICAL HAZARDS OF VOLCANIC ALLUVIAL FANS
Kazuo OKUNISHI (Disaster Prevention Research Institute, Kyoto University); Gokanosho Uji, (611-0011 Japan, Email: okunishi@slope.dpri.kyoto-u.ac.jp); Hiroshi Suwa (Disaster Prevention Research Institute, Kyoto University, Gokanosho Uji, 611-0011 Japan, Email: suwa@slope.dpri.kyoto-u.ac.jp)
Alluvial fans on the foot of volcanoes have high hazard potential because of frequent inundation of debris flows and floods accompanying marked topographic changes. However, the social needs for the development of such lands are ever increasing, because of their high demand for recreational and touring sites. Assessment of hazard potential and regulation of land use are thus urgent problems. We propose fundamental principles for the assessment of hazard potential on the basis of a case study carried out at the Kikkakezawa Fan on the southern foot of Mt. Yatsugatake, central Japan. Existing villages are located below a major spring zone in the alluvial fan, which is fed by the groundwater in the volcanic body. Construction of a new road stimulated land developments along it and further upstream. It has been found that the debris-flow deposits had covered the fan in three geologically distinct ages. The ages of the deposits of new-age and middle-age debris flows are estimated on the basis of aerial photographs and a field investigation to assess their recurrence interval. The three kinds of debris flows are characterized by relative height from the current stream bed and by the area of deposition. Since the hazard assessment is needed for any part of the fan for any time span of the planned land use, it is advisable to define and assess the hazard potential of a fan from which the risk is calculated taking account of the location in the fan, and the time-span and the mode of the planned land use.
JSP23/E/54-A5 1520
THE ADVANTAGES OF HOLONIC DESIGN FOR WARNING AND ALARM SYSTEMS
Gary GIBSON (Seismology Research Centre, 2 Park Drive, Bundoora, Victoria 3083, Australia,
email: gary@seis.com.au)
Warning and alarm systems are near real-time monitoring systems. They may be adversely affected by the events they are seeking to detect, such as a communication failure caused by an earthquake. Holonic systems were developed in manufacturing engineering, and require that each system element involves both task performing and decision making. A holon is an intelligent system element, either human or computer based, that is normally in communication with other holons. A holon is AUTONOMOUS (it can perform tasks alone if communications fail) and COOPERATIVE (overall results are enhanced when holons help each other, and it monitors the health of neighbouring holons, providing an immediate alarm if a failure is detected, and may attempt to compensate for any loss of function).
Holonic systems are designed so that no elements or communication links are critical. It must be accepted that any particular component will fail, and the system must be designed to cope with this. The Internet is a system designed to continue in operation after individual components have failed. An holonic system is one, which self-organises and evolves to dynamically optimise survivability, adaptability, flexibility, efficiency and effectiveness.
Earthquake and tsunami warning and alarm systems are ideally suited to holonic design. They use "Event Oriented Seismology", requiring minimal data flow. Each seismograph may be event triggered, may record continuously and only transmit selected waveform segments on request, and/or may transmit minimal continuous data to facilitate event detection. They respond to requests or issue messages to other holons in the system. Communication can vary from the Internet, to slow digital radio links, or even dial-up telephone. A system is holonic if each element sends and receives information to and from other elements, but continues to function autonomously when communications fail. Any system failure should be immediately reported by one or more system elements. Holonic systems may be very economical because they only perform the tasks that are required. Compared with continuously tele-metered data from non-holonic digitisers, there is a dramatic reduction in total data flow, and usually in operating cost, with enhanced reliability and flexibility.
JSP23/C/U5/W/08-A5 1600
URBAN LOCAL EARTHQUAKE DISASTER RISK INDEX
Yang TING (Geophysics Institute, China Seismological Bureau. Now at Shanghai SeismologicalBureau, No.87, LanxiRd. Shanghai,China, 200062, Email: tyang@263.net); Zhu Yuanqing (ShanghaiSeismological Bureau,No.87,Lanxi Rd.Shanghai,China,200062)
In many modern cities, especially megacities with low seismicity, there exist a lot of hidden disadvantages, except for the frequency of historical earthquake and ground shaking level, that may amplify the influence of earthquakes and cause a catastrophe to them. The Urban Local Earthquake Disaster Risk Index (ULEDRI), which is firstly presented by authors, will highlight those disadvantages with an easily understandable form for city decision-makers, planners, organizations and individuals. ULEDRI is a variation of EDRI, which is a new approach that can directly compare the relative overall earthquake disaster of megacities worldwide, and describe the relative contributions of various factors to that overall risk. Unlike EDRI, whose study unit is the greater metropolitan area, ULEDRI uses the local area of an urban, e.g. administrative district, postal area, as its unit of study. Whats more, depended on the demand of users, ULEDRIs study unit can be a larger one (e.g. every administrative district of city), or a smaller one (e.g. several blocks). As a result of this difference between EDRI and ULEDRI, the objectives, uses and developing approach of ULEDRI will differ distinctly from those of EDRI. ULEDRI involves a large amount of knowledge about earthquake disaster of a wide range of disciplines, and the factors that contribute to overall ULEDRI of a city include those of geophysics, geology, engineering, residents, socio-economics, culture and so on. ULEDRI has the following potential uses. First, this kind of index can serve as a simple tool to directly compare the relative overall earthquake disaster risk of different local area of a city, so the decision-makers and administrators can find where the most dangerous local area is when an earthquake affects the city. Second, through disaggregated ULEDRI, the users can find the reason why a local region has a high overall ULEDRI, and which factor is the most important one that causes this. For city planner and disaster manager, the information will be significant in urban function planning and disaster mitigation. Third, any organization and individual will be able to refer to the index in allocating resources and increasing awareness of disaster. As a sample, ULEDRI of Shanghai, which is based on several districts, has been constructed, and its feasibility and potential application have also assessed.
JSP23/C/U5/E/16-A5 1620
THE GSHAP WORLD MAP OF SEISMIC HAZARD
D. GIARDINI (ETH, 8093 Zurich, Switzerland, email: giardini@seismo.ifg.ethz.ch); G. Grunthal (GFZ, Potsdam, Germany); H. Gupta (NGRI, Hyderabad, India); D. Mayer-Rosa and S. Sellami (ETH, Zurich,Switzerland); K. Shedlock (USGS, Boulder, USA); P. Zhang (SSB, Beijing, China); T. Annaka (Tokyo Electric Power Sevices, Japan); M. G.-Ashtiany (IIEES, Tehran, Iran); K. Atakan (Bergen University, Norway); S. Balassanian (NSSP, Yerevan, Armenia); P. Basham (CTBTO, Vienna, Austria); C. Dimate (Ingeominas, Bogota, Colombia);; M. Erdik (Kandilli Obs., Istanbul, Turkey); M. Garcia (CSIC, Barcelona, Spain); Giesecke (CERESIS, Lima, Peru); K. McCue (AGSO, Canberra, Australia); R. McGuire (Risk Engineering, Boulder, USA); R. Musson (BGS, Edimburgh, UK); S. Riad (Assiut University, Cairo,Egypt); D. Slejko (OGS, Trieste, Italy); V. Ulomov (JIPE, Moscow, Russia)
The Working Groups of the GSHAP regions: Central-North America, Central-Northern Europe, Eastern Asia, Northern Eurasia, Ibero- Maghreb, Adria, the working Groups of the projects: PILOTO, CAUCAS, RELEMR, SESAME, PAIGH-IDRC, EU-QSEZ-CIRPAN.
The Global Seismic Hazard Assessment Program (GSHAP) was launched in 1992 by ILP and ICSU and endorsed as a demonstration program by the UN/IDNDR. The GSHAP promoted a regionally co-ordinated, homogeneous approach to seismic hazard evaluation. Regional activities were concluded in 1992-98; the results have now been compiled in a uniform set of databases and in a world map of seismic hazard expressed in PGA. Support for the GSHAP implementation was provided by ING, Roma, by national and regional institutions, by IASPEI, UNESCO, ICSU, ILP, IDNDR, EU, NATO, INTAS and IGCP. All GSHAP materials (regional report, maps, datasets) can be retrieved on the GSHAP web site at http://seismo.ethz.ch/GSHAP/. The GSHAP world map of seismic hazard will be presented for the first time at the IUGG assembly and will be available for distribution at the assembly.
JSP23/E/33-A5 1640
RISK ASSESSMENT AND MANAGEMENT IN RUSSIA
Shakhramanjyan M.A.(1), Nigmetov G.M.(1), Larionov V.I (1), FROLOVA N.I.(2), Suchzhev S.P.(3), Ugarov A.N.(3) Agency on Monitoring and Forecast of Emergency Situations, Ministry of Emergency Situation of Russian Federation (2)Seismological Center of IGE, Russian Academy of Sciences
(3) Extreme Situations Research Center
At present in Russia the new technologies and procedures of natural and technological disasters monitoring and forecast of their consequences are elaborated and implemented. they are the following: procedure for individual seismic risk and losses assessment and identification of effective response scenarios; technology of operative zonation of the territories according to the rate of forest fires and flooding hazards; procedure of complex risk assessment and mapping with taking into account different natural and technological hazards; technology od estimation of buildings and structures' stability and earthquake resistance with the help of mobile diagnostic complexes; technology of operative monitoring of the territories with the use of remote sensing. All the technologies and procedures are realised on the basis of modern geographical information systems (GIS). The main blocks of the special GIS is described. The examples of individual seismic risk computations for different earthquake prone areas and cities of the Russian Federation, as well as for other countries are given. The influence of secondary engineering geological processes (landslides and liquefaction) is considered. The procedure of acceptable seismic risk level estimation is proposed. The examples of complex risk estimations are also given for the areas where different natural hazards (earthquakes, volcanic hazard, tsunami, flooding, hurricanes and storms, avalanches, forest fires) are possible. The preventive measures plans and measures for reduction the risks from separate hazards are proposed. The maps of operative zonation of the territories according to the rate of forest fires and flooding hazards are presented for some regions of Russia and other countries. The application of the obtained results to disaster management practice may increase significantly the efficiency of measures aimed at risk reduction for population in urban areas.
JSP23/E/39-A5 1700
EARTHQUAKE RISK ASSESSMENTS AND PRACTICAL APPLICATIONS FOR EARTHQUAKE MITIGATION STRATEGIES IN AUSTRALIA
Jack RYNN (Centre for Earthquake Research in Australia, PO Box 276, Indooroopilly, Brisbane, Queensland 4068, Australia, email: sally.brown@uq.net.au)
In response to the United Nations IDNDR program, the Australian IDNDR Co-ordination Committee of Emergency Management Australia facilitated the earthquake zonation mapping of urban areas in Australia as one of its initial projects. The catalyst for this was the devastating 28 December 1989 Newcastle earthquake. A specific methodology was developed which has been expanded to address the national requirements for earthquake mitigation strategies. This involves a multidisciplinary approach integrating, both quantitatively and qualitatively, earth science, engineering, socio-economic, humanitarian, disaster planning, emergency management and community aspects. The results are compiled as an "information resource" in terms of hazard and vulnerability assessments and the integrated risk assessments, earthquake scenarios, potential ground motions and possible damage situations relative to the built and natural environments and the community. the outcomes are translated into practical applications to address awareness and preparedness for earthquake codes,
JSP23/W/11-A5 1720
HYDRODYNAMIC SIMULATION EXTREME STORM SURGES IN AZOV AND
CASPIAN SEAS
Olga TIKHONOVA, Sergei Popov, Guennady Safronov, Oleg Zilberstein (State Oceanographic Institute, Kropotkinski per. 6, 119838, Moscow, Russia, email: oleg@soins.msk.ru)
Problems of storm surges description and prediction are very important because surges often lead to loss of human life and bring substantial damages to national economies. Thus for prevention their fatal consequences it is necessary to forecast storm surges according to available operative meteorological information and to calculate the storm surges characteristics. Besides of that, each extreme storm surge case is very important for determination of long return period characteristics of sea level and currents for hydrodynamic support hydro-technical engineering and marine shelf oil and gas exploration. Design and installation of stationary shelf oil platforms require information about vertical structure of currents. These characteristics are obtained by the 3D hydrodynamic model simulation. In this paper a non-linear 2D and 3D hydrodynamic models were applied for calculation of some extreme storm surges in Azov and Caspian Seas (including the catastrophic cases). The regime of sea level variations was investigated.
GIS mapping, education and training, loss reduction, disaster planning and emergency management. Such projects have been undertaken in the urban areas of Sydney, Southeast Queensland, Newcastle and Melbourne. Particular effort is directed towards real-time simulated earthquake exercises in co-operation with emergency services authorities. Collaboration with several international organisations and other risk projects in Australia is continuing. Although Australia is a moderate seismicity active interplate regime, the record of albeit "rare" earthquake disasters pointedly attests to the need for mitigation strategies.
JSP23/E/40-A5 1740
TOWARDS REAL-TIME MONITORING OF LAVA EFFUSION RATES DURING VOLCANIC ERUPTIONS
Andrew HARRIS and Luke Flynn (HIGP/SOEST, University of Hawaii, 2525 Correa Road, Honolulu, HI 96822, USA, email: harris@kahana.pgd.hawaii.edu)
Determining volumetric effusion rates for lava flows is an important but challenging task. Effusion rates are a major consideration in considering the potential threat posed by a lava flow. For channel-fed flows, higher effusion rates produce flows that are longer, more rapidly moving, voluminous, and aerially extensive than those with low effusion rates. High effusion rate flows thus have greater potential to inflict damage on distant communities with less advance warning. To calculate effusion rates we use satellite-derived (TM and AVHRR) thermal data in a heat balance. High spatial resolution TM data are collected infrequently, but allow high precision. Using TM data for active flows at Kilauea, Hawaii, we obtain effusion rates of 1.76±0.57 and 0.78±0.27 cubic meters per second on 23 July and 11 October 1991, respectively. These rates compare with field measurements of 1.36±0.14 and 0.89±0.09. Using lower spatial resolution weather satellite (AVHRR) data collected at higher spatial resolution (>1 image per day), we obtain similar but more poorly constrained effusion rates. However, comparison with ground-based and TM data for eruptions at Kilauea, Krafla and Etna show that the AVHRR-derived time series reliably show waxing and waning phases of effusive eruptions with high temporal precision.
All of our systems are automated, and with direction reception of TM and AVHRR at the University of Hawaii we anticipate providing a web-based real-time lava flow monitoring tool. This will display current effusion rate time series, up-dated within minutes of satellite overpass at-least once every 6 hours for AVHRR, once every 8 days for TM. This system will be similar to our GOES-based real-time hot spot monitoring site at http://volcano1.pgd.hawaii.edu.
Saturday 24 July AM
Presiding Chair: A Ansal (Istanbul Technical University, Istanbul, Turkey)
Concurrent Poster Session
SEISMIC RISK MAPS AND SCENARIOS: TOOLS FOR THe
PROTECTION AGAINST EARTHQUAKES
JSP23/W/17-A6 0830
THE LONG AND WIDING ROAD FROM EARTHQUAKES TO DAMAGE
A. Ansal (Istanbul Technical University, Faculty of Civil Engineering, Maslak, Istanbul 80620, Turkey, tel: (90)-212-285 3702, fax: (90)-212-2856006, e-mail: ansal@itu.edu.tr); D. SLEJKO (Osservatorio Geofisico Sperimentale, P.O.Box 2011, 34016 Trieste, Italy, tel: (39)-40-2140248, fax: (39)-40-327307, e-mail: dslejko@ogs.trieste.it)
The impact of destructive earthquakes has two faces: one in the short term and the other in the long term. The first is given by the number of victims, damaged structures and direct economic losses. The second is given by the negative influence on the social structure in the following years. Although the direct economic loses can be absorbed by the country, especially with international support, in most cases the social structure suffers permanent damages. The recent earthquakes of Northridge and Kobe have shown the long term problems caused respectively to the insurance companies and private habitants. This is one of the reasons why in seismically active countries (e. g.: Italy), a general private insurance against natural calamities is now being implemented. The knowledge on seismic risk is, therefore, fundamental for loss reduction. Seismic hazard maps at national level are the basic tool for defining the national seismic zonation which is relevant for planning adequately new settlements and constructing properly new buildings. The choice of the hazard parameter to consider for zonation is critical when the description of the whole contents of the seismic excitation is desired. However, these maps are only valid at large scales and local effects are not taken into consideration. Seismic risk maps at national scale are strategic for planning the policy for retrofitting old buildings in the presence of limited investments: their definition in a quantitative manner remains mainly a research topic for the difficulty of quantifying properly the ingredients. Risk scenarios at regional to local scale are very popular in recent years as they have the potential to limit earthquake victims and structural damage when a dangerous event is presumed to take place. In fact, based on the information and analysis concerning earthquake resistance capacity of existing buildings and structures, strengthening and retrofitting programmes can be optimised. The good knowledge …
JSP23/E/34-A6 0850
DETERMINISTIC VS. PROBABILISTIC EARTHQUAKE HAZARDS AND RISKS
Robin K. MCGUIRE (Risk Engineering, Inc., 4155 Darley Ave, Suite A, Boulder, Colorado, 80403, USA, email: mcguire@riskeng.com)
Deterministic vs. probabilistic approaches to assessing earthquake hazards and risks have differences, advantages, and disadvantages that often preclude the use of one over the other. Factors that influence the choice include the decision to be made (i.e. the purpose of the hazard or risk assessment), the seismic environment (whether the location is in a high, moderate, or low seismic risk region), and the scope of the assessment (a single-site risk, a multi-site risk, or risk to a region).
Decisions coming from earthquake assessments include selection of design or retrofit criteria and levels, financial planning for earthquake losses, and planning for emergency response and long-term recovery. The more quantitative the decision to be made, the more appropriate is probabilistic hazard and risk assessment.
For high seismic regions (e.g. California or Japan) where the largest earthquakes occur every 100-300 years), a deterministic scenario for the largest event will allow details to be examined such as ground motion effects caused by rupture propagation. In low seismic regions, extreme deterministic scenarios will have probabilities of occurrence that are too low to be useful for most decision purposes.
Specific site analyses generally require a probabilistic approach. Multiple-site analyses (e.g. for a portfolio of exposed or insured properties, or a lifeline) often require a probabilistic analysis because of multiple variables and complexities of the system, and a deterministic check can be misleading. Regional assessments often benefit most from deterministic models.
JSP23/C/ST3/E/21-A6 0910
METHODOLOGICAL CONSIDERATIONS OF PROBABILISTIC SEISMIC HAZARD MAPPING
R.M.W. MUSSON (British Geological Survey, West Mains Road, Edinburgh, EH9 3LA, UK,
Email: R.Musson@bgs.ac.uk)
The study of seismic hazard is perhaps the most practically oriented aspect of earthquake seismology. As such, it should not be treated in an idealised or academic manner, but with regard to the needs of the consumers of the final product. This has important consequences when it comes to the topic of probabilistic seismic hazard maps. Who are these for? Historically, early studies of probabilistic seismic hazard tended to be done for engineers for specific design requirements. Consequently, there has been a tendency to treat seismic hazard maps as a sort of pan-national study for engineers, who can identify the design requirements for any site by picking them from the map. A dissenting point of view argues that seismic hazard maps are by their very nature too generalised to be used in this way; that such maps provide a first indication of relative hazard and should not be a substitute for site studies. There are, therefore, a number of interesting and important methodological questions to be asked: what are the practical differences in undertaking a seismic hazard map from calculating hazard for a site? Should probabilistic seismic hazard maps have the same degree of conservatism as site studies? How can seismologists meet the needs of different audiences? An engineer may think in terms of ground acceleration, but this parameter probably means little to people in other professions who still need access to seismic hazard data, but in a form they can understand. These are questions that need to be addressed directly; one should not leave them to be answered by default.
JSP23/E/03-A6 0930
EARTHQUAKE SCENARIOS FOR SWITZERLAND
FAEH, D., Bay, F., Giardini, D., Kind, F., Mayer-Rosa, D., Sellami, S. (Swiss Seismological Service, ETH Zurich); Lang, K., Bachmann, H., Wenk.,T. (Institute of Structural Engineering, ETH Zurich); Noack, T., Huggenberger, P. (Institute of Geology, University of Basel)
The goal of our project is to develop a method for the estimation of expected damage from earthquakes. The presentation is giving an overview of the state of the project, which includes, the modelling and mapping of ground motion on a regional scale for the area of Switzerland, and on a local scale for the Basel area, the classification of the vulnerability of buildings to earthquake ground motion for some target areas, and the realization of scenarios. We will present the deterministic seismic hazard in form of scenario ground motion maps. This can be done on a regional scale or on a local (microzonation) scale. On the regional scale the scenario ground motion maps should include significant earthquakes in a regional sense. Maps will then display ground motion with different probabilities of occurrence in different locations. On a local scale, ground motion scenario maps are most appropriately computed for single possible earthquakes, and these maps can be combined with a vulnerability assessment of existing structures. In this combination the scenario maps include the level and duration of shaking. Furthermore they make it possible to identify localities where ground is likely to fail through liquefaction or landslides, and they enable us to pinpoint structures that are likely to be severely damaged and to find weak links in life-line structures. Such studies can be done with different levels of detail. The project will contribute to the necessary seismic upgrading of existing buildings, as well as to reliable earthquake resistant design of new structures, to the education of the general public, the emergency planning and it will serve as a reminder that there is a large difference between what is expected from probabilistic maps and what is a possible event.
JSP23/E/08-A6 0950
REGIONAL AND LOCAL SEISMIC HAZARD ASSESSMENT
A. MARCELLINI, R. Daminelli, G. Franceschina e M.Pagani (Istituto di Ricerca sul Rischio Sismico, CNR, via Bassini 15, 20133 Milano, Italy, e-mail: marcel@irrs.mi.cnr.it)
Site effects can produce, at a local scale, abrupt changes of the ground motion as also instability phenomena such as landslides and soil liquefaction; microzonation studies are the scientific response for the evaluation and mitigation of this kind of phenomena. Seismic microzonation generally produces on a municipal scale Landuse planning criteria and defines seismic actions for engineering purposes. Seismic codes instead, are issued on the basis of Seismic Hazard studies, that is, seismic actions and seismic zonation are a direct consequence of a probabilistic seismic hazard, generally assessed considering a 474 yr R.P. In other words seismic actions assessment is biased by the inefficiency of seismic hazard evaluation procedure to account properly of parameters controlling the ground motion, mainly due to the limited number of factors used in the attenuation laws. It should be pointed out that till now this limits appears unavoidable due to the scarcity of strong motion accordings. Microzonation investigation can overcome these limitations, but only if the reference input motion is properly assessed by adopting the same level and the same criteria of protection used to issue seismic codes at national level. The case study here presented refers to a zonation and microzonation investigation performed in the Forlì provincia (Emilia-Romagna) for the purposes of seismic prescriptions to be issued both at regional and local level and we will main focus on the importance of multiple approach for the definition of the reference input motion.
JSP23/C/U5/W/06-A6 1010
NEAR-FIELD GROUND MOTIONS
N. AMBRASEYS (Imperial College, London)
The assessment of earthquake hazard of interest to the engineer must be based on the analysis of reliable observational data than on statistics of many records and seismological parameters of questionable quality. Theoretical methods for the prediction of ground motions have become highly developed, whilst knowledge of the observational material is usually lacking. Differences between attenuation laws arise from the size and distribution of the sets of data used in their derivation and from the use of different magnitude scales, which introduce significant bias in the results. In addition, the correction of records and the modelling of attenuation laws and fitting method used to regress the data are sources of systematic errors. Taking some of these differences into consideration we find no significant variation of attenuation laws among different regions for shallow earthquakes, and a remarkable agreement between attenuation laws derived for Europe, western North America and New Zealand. They are all within the standard deviation of the determinations, which are not better than by a factor of 1.7 for accelerations. The importance of the vertical acceleration needs further investigation. However, the observation that the ratio of peak vertical zero-period or spectral value, to that of the horizontal, can be larger than 1.0 does not necessarily imply large vertical accelerations or spectral ordinates, most certainly when these maxima occur simultaneously. Also the assessment of peak and spectral ground displacements, which is of some engineering importance, needs further investigation. Near-field ground motions from medium and large magnitude earthquakes associated with surface faulting or, from sites on low-strength deposits, contain a significant component of permanent displacement, not accounted or in standard base-line correction procedures. An answer to these question is needed in order to rank these effects among other variables, and clarify the need to include or exclude them from building codes.
JSP23/W/18-A6 1050
ASSESSMENT OF STRONG EARTHQUAKE GROUND MOTIONS FOR NEAR-FAULT CONDITIONS
Mustafa ERDIK, Eser Durukal (Bogazici University, Kandilli Obs. And Earthq. Res. Inst. 81220 Cengelkoy, Istanbul, Turkey, email: erdik@boun.edu.tr, durukal@boun.edu.tr)
Near-fault ground motions are strongly influenced by the earthquake faulting mechanism. Especially, the motions with periods above 1s may follow certain radiation patterns, predicted by equivalent double-couple source models, and exhibit distinct long period pulses with amplitudes depending on the orientation of the site with respect to the rupture direction. Widely use predictive earthquake engineering tools, such as empirical attenuation relationships and spectral shapes fail in the assessment of such near fault motions. Deterministic theoretical predictions of the ground motion can be achieved by convolution of the Green’s Functions and the slip function. Such deterministic predictions cannot be extended into the frequency regions above 1Hz, since, high frequency ground motions are controlled by the heterogeneities in the fault rupture, which cannot be accounted for in a deterministic manner. This requires either the use of stochastic source models or the stochastic treatment of the high frequency components in the ground motions.
Based on these developments a state-of-the art hybrid procedure is developed for the assessment of the time history of the DBE (or SEE) ground motion for important engineering structures near major faults. The essential elements of the procedure can be listed as follows: (1) Assessment of the source parameters of the DBE motion associated with the corresponding return period for specific conditions of site and seismicity; (2) Deterministic assessment of the low frequency (DC-1Hz) ground motion, at the outcrop of a reference soil layer, due to rupture of seismic faults using numerical simulation; (3) Use of a Boore (1983) type stochastic simulation method to complement the deterministic low frequency ground motion with high frequency (1Hz- 50Hz) components; (4) Combination of the two parts of ground motion to yield a site-specific simulation for a frequency range of DC-50 Hz.; and (5) Site response analysis, if required, to include the local wave propagation effects in the soil media above the reference soil layer.
An example that illustrates the application of this procedure is provided.
JSP23/E/01-A6 1110
MODIFICATIONS TO SEISMIC HAZARD DUE TO SITE-CITY INTERACTION
Pierre-Yves BARD, Philippe Gueguen (Laboratoire Central des Ponts- et-Chaussies and Observatoire de Grenoble, BP 53 - 38041 Grenoble Cedex - France,
email: Pierre-Yves.Bard@lgit.obs.ujf- grenoble.fr); Jean-Frangois Semblat (LCPC, 58 Bd Lefebvre, 75732 Paris Cedex 15 - France); Martin Cardenas and Francisco Chavez- Garcia (Coordinacion de Ingenieria Sismologica, Instituto de Ingenieria, UNAM, Ciudad Universitaria, Apdo. Postal 70-472, Coyoacan, 04510 Mixico, D.F)
Soil-structure interaction has long been known to significantly affect the seismic behavior of large buildings on soft soils. A few observations, and several computations as well, recently indicated the possibility for significant feed-back effects from buildings into the soil: the waves radiated back into the soil from the soil-struture interface are trapped in the surface layers when the impedance contrast at depth is large enough, so that the building is acting as a secondary source of surface waves. This phenomena has been shown to be maximum in case of coincidence between the building and ground natural frequencies: the worst case corresponds to the matching of fundamental frequencies, and induces ground motion modifications of at least 30 % in time- domain amplitudes within distances up to 5 to 10 times the building base dimensions. The question then arises of the possibility of large-scale site-city interaction due to the quasi- random superposition of such phenomena for a large number of buildings in a given city, or in a given quarter, which, in turn, raises two issues: Is the "free-field record" concept relevant in such areas? And will the construction or destruction of some buildings modify locally the hazard? The aim of the presentation is not to answer these questions, but simply to briefly review the reasons why these issues have to be addressed, and to present some preliminary, first order computations exhibiting significant effects not only for "exceptional" configurations such as Mexico City, but also for much more common situations with "ordinary" sediments and "ordinary" buildings.
JSP23/W/20-A6 1130
THE CYCLIC BEHAVIOUR OF SOILS AND EFFECTS OF GEOTECHNICAL FACTORS IN MICROZONATION
Atilla ANSAL (Istanbul Technical Uni, Civil Engng., Maslak, Istanbul, Turkey, email:ansal@itu.edu.tr)
The behaviour of soils subjected to cyclic loading is briefly reviewed. The results obtained from cyclic triaxial, simple shear and torsional hollow cylinder tests conducted on undisturbed, normally consolidated clay samples subjected to different shear stress amplitudes and different loading patterns are summarised. Results of the tests conducted under uniform cyclic stresses to evaluate "cyclic yield stress" and "threshold cyclic shear stress" are presented. The effects of cyclic loading on static shear strength and induced settlements due to pore water pressure dissipation are discussed. Cyclic tests performed to evaluate the liquefaction susceptibility of laboratory prepared and undisturbed sands and silty clayey sands are briefly reviewed in the light of the findings reported in the literature.
Geotechnical site conditions is one of the main factors controlling earthquake forces affecting structures. Therefore, in analysing the observed damage in previous earthquakes and for microzonation studies, this factor and its coupled effect with earthquake source characteristics need to be evaluated. The earthquake source characteristics induced by a tectonic source mechanism are on macro level and are not sufficient to explain the variations in structural damage observed within short distances. On the contrary, the geotechnical site conditions that can be very different due to changes in the thickness and properties of soil layers, depth of bedrock and water table, can have more dominant influence on damage distribution. In addition the effect of coupling between site and source characteristics may modify earthquake ground motion characteristics significantly. There are large numbers of instrumental field observations obtained during recent earthquakes reflecting the coupled effects of geotechnical site and earthquake source characteristics. During earthquakes soil layers are subjected to multi-directional cyclic stresses with different amplitudes and frequencies that lead to cyclic deformations and to changes in stress-strain and strength properties of soil layers. Extensive laboratory, model and field studies were conducted concerning response of soils subjected to cyclic stresses. Significant improvements were achieved in the field of insitu tests to obtain more reliable soil properties. Numerous analytical and empirical relationships were developed to model the behaviour of soil deposits subjected to earthquake excitations. From an engineering perspective, it is possible to investigate the properties of geo-technical site conditions in detail and analyse the response of soil layers with sufficient accuracy.
JSP23/E/05-A6 1150
LOCAL SITE EFFECTS AND DYNAMIC SOIL BEHAVIOUR
Erdal SAFAK (U.S. Geological Survey, Box 25046, MS 966, Denver, CO 80225, USA,
email: safak@usgs.gov)
Amplitudes of seismic waves increase significantly as they pass through soft soil layers near the earth's surface. This phenomenon, commonly known as site amplification, is a major factor influencing the amount of damage on structures. It is crucial that site amplification is accounted for when designing structures on soft soil sites. The characteristics of site amplification, at a given site, can be estimated by analytical models, as well as field tests. Analytical models require as inputs the geometry of all soil layers from surface to bedrock, their dynamic properties (e.g., density, wave velocity, damping), and the incident bedrock motions. Field tests involve recording and analyzing the dynamic response of sites to artificial excitations, ambient forces, and actual earthquakes. The most reliable estimates of site amplification are obtained by analyzing the recorded motions of the site during earthquakes.
This paper presents a review of the models and methods that are used to characterise site amplification, and introduces some new ones with better theoretical foundations. The models and methods discussed include spectral and cross-spectral ratios, response spectral ratios, constant amplification factors, parametric models, physical models, time-varying filters, methods for downhole records, single-station methods, and generalised inversion techniques. The paper also examines the validity of one-dimensional models, in comparison to 2D and 3D models, and shows the effects of surface waves and surface-to-bedrock topography on site amplification estimates. The paper concludes that probabilistically cross-spectral ratios give more reliable estimates of site amplification than spectral ratios. Spectral ratios should not be used to determine site amplification from downhole-surface recording pairs because of the feedback in the downhole sensor. Response spectral ratios are appropriate for low frequencies, but overestimate the amplification at high frequencies. One-dimensional site amplification models are not appropriate for sites in deep sedimentary basins that are susceptible to generating surface waves. The surface topography…
JSP23/E/44-A6 1210
THREE DIMENSIONAL PLATE KINEMATICS IN ROMANIA
Georg Dinter (Department of Geodesy, University of Karlsruhe, D-76128 Karlsruhe, Germany,
email: dinter@gik.uni-karlsruhe.de); Guenter SCHMITT (Department of Geodesy, University of Karlsruhe, D-76128 Karlsruhe, Germany, email: schmitt@gik.uni-karlsruhe.de)
Since 1996 the Collaborative Research Center (CRC)461 ``Strong Earthquakes: A Challenge for Geosciences and Civil Engineering'' is funded by the Deutsche Forschungsgemeinschaft (German Research Foundation) as a German Contribution to the UN initiative ``International Decade of Desaster Reduction'' (IDNDR). A central project of this CRC is the subproject B1 ``Three dimensional Platekinematics in Romania'' which is installed to detect borders of the geotectonic plates in Romania, to quantify their three dimensional movement rates and to determine in detail the deformation of each geotectonic unit in the Vrancea Region as a contribution to the research of the tectonic cause of the intermediate depth earthquakes in this region. These aims shall be accomplished by repeated GPS-measurements in a network which has been installed in 1997 and measured until now in 1997 and 1998. This network is consisting of 26 stations, covering an area of 250 x 380 km with the Vrancea area as the centre. The frame is given by six stations of the CEGRN (Central European Geodynamic Regional Network) of the CEI-Initiative CERGOP, for which co-ordinates and velocities in a global tectonic scenario are available. The paper gives information about the tectonic background, the geodetic network, the GPS-measurements and the achieved accuracy’s and first results of deformation analyses.
Saturday 24 July PM
Presiding Chair: D Slejko (Observatorio Geofisico Sperimentale, Trieste, Italy)
JSP23/L/06-A6 1400
EVALUATION OF VULNERABILITY OF CIVIL ENGINEERING STRUCTURES
Mauro DOLCE (Department of Structures, Soil Mechanics, Applied Geology, University of Basilicata, Potenza, Italy)
The impact of earthquakes on man-built systems (buildings, groups of buildings, lifelines, cities, etc.) is usually expressed in terms of losses. Loss assessment is a highly complicated task, involving, besides structural engineering and seismology, many disciplines such as geotechnical, transport, hydraulic and electrical engineering, geology, urban planning, social and economic sciences, etc. However most of the losses results from the consequences of direct damage to civil engineering constructions, particularly buildings. The evaluation of their seismic vulnerability is then a fundamental step in the process of determining the impact of earthquakes on man-built systems. This is usually assessed in terms of seismic risk in a period of time (e.g. one year, hundred years), i.e. in terms of probability or of expectation of losses during that period due to all the possible arriving earthquakes. This representation is very general but presents many drawbacks such as the difficulty of interpreting the results in practical terms and the difficulty of expressing and quantifying losses for territorial systems. In fact they are highly dynamical systems, whose future developments are difficult to forecast, particularly after the occurrence of an earthquake. A long term loss prediction is therefore not much significant, if it is referred to the current situation or even to the current trend.
Recently the interest of researchers and operators has been focused on risk scenarios, where the impact of a given earthquake is investigated and quantified. This approach permits to better understand the behavior of the built environment under study and to take the countermeasures aimed at reducing its impact. Scenarios can be prepared considering different aspects of the earthquake consequences. Different levels of accuracy can be assumed in the preparation of a scenario, starting from the assessment of shaking intensity and characteristics, through damage prediction up to loss assessment. Obviously the accuracy levels in the different steps must be consistent.
The assessment of damage to constructions deserves a special attention. In this respect, two ...
JSP23/L/07-A6 1420
FROM VULNERABILITY OF OBJECTS TO VULNERABILITY OF SYSTEMS
Carlo GAVARINI (Universita' La Sapienza, Roma, Italy)
First of all the paper outlines the current conceptions relevant to vulnerability of constructions, describing the various approaches and the different research levels, then, in the second part, a more global vision is developed in which the constructions belonging to an aggregate, or a centre, or a city, or a territorial area, are considered as a part of a vulnerable system, with all the complexity that it brings about, in terms of different variables that must be taken in consideration, properties and values that are in danger, disciplinary, cultural and historical aspects that must not be ignored.
Assessment of vulnerability is strictly connected with another basic problem, risk mitigation, that will be briefly considered in the third part, analysing the interrelations between vulnerability and environment aggressions. Also here we must point out how today it is a common exigency, also as regards technical codes, to abandon the sectional vision of objects considered separately and to promote instead the above mentioned ‘picture in picture’ vision applied to systems, better said to complex systems, specially when the areas in question are rich with particular ‘objects’ with a ‘cultural value’, such as historical buildings and monuments.
Lastly, in the fourth part, we return to deal with single objects, giving a short account of problems specific to monuments and in particular to churches subjected to seismic actions; referring to studies regarding the Cathedral of Noto, partially collapsed in 1996 and now in course of reconstruction.
The need for experiments, either real or virtual, is recognized as a key for understanding and classifying the…
JSP23/E/19-A6 1440
LOSS ESTIMATION: A POWERFUL TOOL FOR RISK ASSESSMENT AND MANAGEMENT
Fouad BENDIMERAD (Risk Management Solutions, Inc., 149 Commonwealth Drive, Menlo Park,
CA 94025, USA; email: fouadb@riskinc.com)
Earlier loss estimation studies were limited to investigating particular scenarios and were carried out by highly specialized experts. Today, loss estimation techniques are translated into efficient software applications that are accessible by a large constituency of end-users. These techniques offer a high level of analysis sophistication and enable users to perform various "if-then" scenarios to study the sensitivity of the results, to develop a better understanding of the outcomes and to gain insight on the consequences of the findings and decisions.
Loss estimation techniques have benefited from the advances in information technology. Modularity, encapsulation and a new generation of computer codes such as C++, provide a logical and flexible structure for organizing the analytical procedures involved in loss estimation. These techniques organize the multitude of analytical calculations into modules that are logically inter-related by hierarchical rules. This flexible architecture permits ease in development, testing, validation, maintenance and upgrade. The study region is divided into geographical units (Geo-Units) such as postal codes or census tracks. The data, calculations and results are then associated with the centroid of the Geo-Unit. The aggregated results from the Geo-Units yield the results for the study region. Geographical Information Systems (GIS) and Relational Database Management Systems (RDMS) are used to organize data in data warehouses, to manipulate data during analysis, and to associate results to geographical regions from which they can be queried, aggregated and/or mapped. GIS and RDMS also allow for easy display of input and output (in standard reports and maps) providing a critical functionality for communication of outcomes to end-users. Loss estimation has become a critical tool to the insurance industry and is quickly being adopted by a wide range of users including emergency managers and planners. The key to this expansion is the integration of new information technologies that gave these techniques greater analytical capabilities, flexible architecture, and user-friendliness.
JSP23/C/U5/E/15-A6 1500
GLOBAL SEISMIC HAZARD AND RISK ASSESSMENT
YONG CHEN, Qi-fu Chen, Ling Chen, Juan Li and Jie Liu (No. 63, Fuxing Avenue, China Seismological Bureau, Beijing 100036, P. R. China)
A global seismic hazard assessment was conducted using the probabilistic approach in conjunction with a modified means of evaluating the seismicity parameters. This method is applicable to both oceanic and continental regions, and for any specific duration of time. It can be used for those regions without detailed geological information or where the relation between existing faults and earthquake occurrence is not clear.
Most seismic risk studies use a probabilistic approach in which predicted damages in various categories of structure and facilities in the region in concern are estimated and added together to obtain a total loss for particular intensity ranges. We have used an alternative means of estimating earthquake losses based on several macroeconomic indices such as the gross domestic product (GDP) and population. A global seismic loss map is then compiled.
The expected losses(in USD) of selected countries and regions for the next 50 years are as follows:
World 949 (USD), Asia 563 (USD), European 184 (USD), N.America 115 (USD),
S.America 60 (USD), Oceania 12 (USD), Japan 390 (USD), USA 66 (USD), China 17 (USD)
JSP23/W/16-A6 1520
SEISMIC HAZARD MAPPING FOR ADMINISTRATIVE PURPOSES
L. Peruzza (C.N.R. Gruppo Nazionale Difesa Terremoti, c/o OGS, Trieste, Italy); A. Rebez and
D. SLEJKO (Osservatorio Geofisico Sperimentale, Trieste, Italy, tel: (39)-40-2140248,
fax: (39)-40-327307, e-mail: dslejko@ogs.trieste.it)
Local site conditions strongly influence the seismic hazard assessment, even if done using standard probabilistic techniques, with average soil classification. GIS applications, nowadays, enhance these variations, without entering into a detailed microzonation study, that is not possible at wide, regional scale. On the other side, the administrative border of municipalities remains the basic units to face the problems of legislative measurements devoted to risk evaluation and reduction. The aim of this paper is to present maps of different hazard parameter devoted to better represent the free field shakebility in NE Italy. The dominant soil in each municipality has been classified, taking into account the location of buildings and structures: then soil dependent hazard estimates have been performed and mapped, according to the some of the criteria leading the new proposal of seismic classification in Italy.
JSP23/W/29-A6 1600
EARTHQUAKE HAZARD ASSESSMENTS FOR THE GULF OF CORINTH (CENTRAL GREECE) AND KRESNA REGION (SW BULGARIA)
Vladimír SCHENK, Zdeka Schenková and Pavel Kottnauer (all at Institute of Rock Structure and Mechanics, Academy of Sciences, CZ-182 09 Praha 8, The Czech Republic,
email: schenk@ irsm.cas.cz)
The earthquake hazard calculations were realised for two seismically high-active European zones, for the area round the Gulf of Corinth (Central Greece) and for the Kresna region (SW Bulgaria). To make reliable earthquake hazard calculations all available data were collected. For the Gulf of Corinth data of the National Observatory of Athens compiled by Drakatos, Kalogeras and Papadopoulos and as well the published earthquake catalogues, geological and geophysical materials (Ambraseys & Jackson 1990, Ganas & White 1996, Hatzfeld et al. 1990, Makropoulos 1985, Papazachos 1988, Papazachos & Kiratzi 1993, 1996, Papazachos et al. 1991, 1996, Shebalin et al. 1974) were applied. Simultaneously, for the Kresna region similar available data of the Geophysical Institute, Bulgarian Academy of Sciences, were sent to us by Ranguelov and Shanov. All these data allowed seismogenic zones with respect to earthquake occurrence and main tectonic structures to be delineated, dependent events from independent ones to be identified, an earthquake regime per requested observation period and/or a size of the area to be normalised, a maximum possible earthquake to be assessed and an acceptable attenuation law to be applied. Every quantity was statistically tested in order to be possible to introduce the logical tree of the input parameters to the hazard calculations. A reliability of the earthquake hazard calculations in common practice will be discussed. The presented calculations were realised under the EC INCO-Copernicus ASPELEA Project No ERBIC 15CT97 0200.
JSP23/C/U5/W/09-A6 1620
EARTHQUAKE DISASTER MITIGATION AND EMERGENCY RESPONSESYSTEM (EDMERS) OF SHANGHAI BASED ON GIS
YANG TING (Geophysics Institute, China Seismological Bureau. Now at Shanghai Seismological Bureau, No.87, Lanxi Rd. Shanghai,China,200062, Email: tyang@263.net) Zhu Yuanqing and Song Jungao (Both at ShanghaiSeismological Bureau,No.87, Lanxi Rd.Shanghai,China,200062)
As the largest city of China, Shanghai is also under the earthquake threat. In order to understand how severe disaster Shanghai will be suffered and what should be done by government when a possible earthquake affects the city, the Earthquake Disaster Mitigation and Emergency Response System (EDMERS) has been developed based on Geographic Information System (GIS). The EDMERS mainly includes two subsystems and several databases. The first subsystem, rapid earthquake damages estimation subsystem, will provide the rapid estimation of all kinds of earthquake damages according to the real earthquake parameters, (the origin time, epicenter location and source depth) which determined by Shanghai Telemetry Seismic Network in minutes while a destructive earthquake occurs. The second subsystem is the emergency response, in which the following emergency responses should be completed in time after a shock: determining the rescue scheme, evacuating victims, coping with dangerous materials, making decisions against fire following earthquake. The databases of EDMERS include building information, lifelines, soil conditions, aerial photographs, historical earthquake catalogues and so on. The following features of EDMERS should be highlighted: first, making use of GIS can enable the system to process the spatial data in a reasonable way, for example, The overlay and buffer functions of GIS can deal with the comprehensive effect of damage of buildings and lifelines. The network analysis of ARC/INFO can be directly used in emergence response such as victim evacuation and pathfinding. Second, emergence response can carry out on the base of real damage conditions by integrating damage estimation subsystem and emergence response subsystem. Third, using remote sensing, namely aerial photograph as an auxiliary tool, make EDMERS visual, vivid and informative.
JSP23/E/15-A6 1640
FIELD SURVEY OF TSUNAMI DISASTER IN PAPUA NEW GUINEA ON 17 JULY 1998
Yoshiaki KAWATA ( Research Center for Disaster Reduction Systems, DPRI, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan, email: kawata@drs.dpri.kyoto-u.ac.jp)
On the evening of Friday 17 July at about 7:30 p.m. a breaking wave from a massive tsunami swept across the sand bar that forms the outer margin of Sissano Lagoon, west Sepik, PNG. Initial reports claimed that the wave was between 7 and10m and that up to 3,000 persons were killed or missing. This seemed to be an unusually damaging tsunami given the size of the earthquake. Members of the International Tsunami Survey Team decided that a field survey was necessary as soon as possible to try and determine the true value of the maximum run-up and to accurately map the run-up distribution along the coast. The first surveys to the Sissano region confirmed the 7 - 10m wave reports and even found place where the waves were larger - up to 15 m. The severe damage and extreme wave heights were confined to a relatively short (30 km) stretch of coast between Aitape and Sissano Village. The survey was conducted by a multi-national team with representatives from Japan, the United States, Australia, and New Zealand. The team was broken up into two groups, the Japanese and everyone else. By the numerical estimation, it is impossible to get such gigantic tsunamis with the earthquake magnitude of 7.0. We found many marks of liquefaction at the sand bar and many residents reported that they had three earthquakes and middle one was the most severe. Therefore, we concluded that the earthquakes were not slow earthquake. Numerical simulation models of submarine landslide show good agreement with tsunami heights and their longshore distribution.
JSP23/C/U5/E/23-A6 1700
PRECISE TOPOGRAPHIC AND GEOPHYSICAL SURVEYS OFF SISSANO LAGOON, NORTHERN PAPUA NEW GUINEA
TAKESHI MATSUMOTO(1), David Tappin(2) and R/V KAIREI KR98-13 Cruise Scientific Party 1) Japan Marine Science and Technology Center (JAMSTEC), 2-15, (BNatsushima- cho, Yokosuka 237-0061, Japan (2) British Geological Survey, Keyworth, Nottingham, UK
The northern coast of Papua New Guinea suffered from a M7.1 earthquake and aftershock events which occurred on July 17, 1998. A large-scale tsunami also occurred just after the earthquakes. KR98-13 Cruise by the Research Vessel KAIREI was carried out in January 1999 in order to locate the possible seismic faults and/or underwater landslides as the source of tsunami. Precise topographic and other geophysical mapping off Sissano Lagoon, in the area of 200km (E-W) and 120km (N-S), was completed after the 9 days' survey.
The study area is characterised by enormous amount of fan sediment supply from Sissano Lagoon, deep-sea canyons on the shelf, arc-shaped slump and offshore strike-slip faults. Straight small-scale submarine canyons and valleys are eroding the shelf slope. The meandering canyon is located on the old shelf to the north of Aitape. Topographic features caused by landslides are recognised at numerous sites of the study area. Most of them are old, and the most recent is located 25km north-east off the Sissano Lagoon. The most prominent of the many tectonic faults located in the study area is E-W trending escarpment, the length of which is about 40 kilometres, recognised 25 kilometres north of Sissano Lagoon.
The result of simplified numerical modelling of tsunami propagation by use of the new bathymetric data shows that the distribution of maximum wave height is in good agreement with the observation. This suggests that the bottom topographic feature is an important factor to amplify the wave and to generate the focused tsunami runup, and that both earthquake faulting and underwater landslide should be taken into account as possible origins of the tsunami.
JSP23/C/U5/W/19-A6 1720
SUPER DENSE REAL-TIME MONITORING OF EARTHQUAKES: SUPREME
Fumio YAMAZAKI (Institute of Industrial Science, The University of Tokyo, 7-22-1 Roppongi, Minato-ku, Tokyo 106-8558, Japan, email: yamazaki@iis.u-tokyo.ac.jp); Yoshihisa Shimizu, Wataru Nakayama and Ken-ichi Koganemaru (all at the Center for Supply Control and Disaster Management, Tokyo Gas Co., Ltd., 1-5-20 Kaigan, Minato-ku, Tokyo 105-8527, Japan, email: yshimizu@tokyo-gas.co.jp)
To cope with earthquake-related secondary disasters, city gas companies in Japan have promoted several countermeasures in the last two decades: increasing seismic resistance of facilities and pipelines, segmentation of gas networks into blocks, earthquake monitoring by seismometers, installation of intelligent gas meters with a seismic sensor etc. As one of such earthquake countermeasures, Tokyo Gas Company introduced an earthquake monitoring and rapid damage assessment system, SIGNAL, with 331 SI-sensors, which measure the peak ground acceleration (PGA) and spectrum intensity (SI) at district regulator stations. The strong motion indices and the results of damage estimation are used for the decision-making whether or not to shut off gas supply.
Recently Tokyo Gas further developed new SI-sensor, having several new functions with the much cheaper price. The new SI-sensor can store acceleration time histories in its IC memory and send monitored strong motion indices to the Supply Control Center through public telecommunication lines. The new sensors will be installed at all the 3,600 district regulator stations with in the next 8 years. The new SI-sensor network is named SUPREME (Super-Dense Real-time Monitoring of Earthquakes), which may be the most dense seismic monitoring network in the world. The data from the network will significantly contribute to the strong ground motion research as well as promote seismic safety of the greater Tokyo Metropolis.
JSP23/W/00-A6 1740
APPLICATION OF POTENTIAL FIELD ANALYSIS …IN INTRAPLATE SEISMIC RISK ASSESSMENT
GUO
Abstract not available at the time of going to press
Monday 26 July AM
Presiding Chair: S McLean (NGDC/NOAA, Boulder, Colorado, USA)
Concurrent Poster Session
NEW PHENOMENA, APPROACHES AND TECHNIQUES
JSP23/C/U5/W/18-B1 Invited 0830
POTENTIAL OF DISRUPTION OF HUMAN ACTIVITIES ON EARTH AND IN SPACE AS A CONSEQUENCE OF THE INTERACTION BETWEEN THE SOLAR CORONA AND EARTH'S MAGNETIC FIELD
Gordon ROSTOKER (Department of Physics, University of Alberta, Edmonton, Alberta, Canada
T6G 2J1, email: rostoker@space.ualberta.ca)
Over the past few decades, mankind has become increasingly dependent on various technologies which have helped greatly to improve the standard of living around the world. Two examples of such technologies that have had an enormous impact on human activities are global communications and the provision of readily available electric energy through the development of large transmission grids. Unfortunately, with the advent of new technologies comes human dependence on them. The use of satellites for communications and position finding purposes serves as a useful example of this dependence. It is now recognised that both geostationary communications satellites and the position-finding GPS satellites are vulnerable to the energetic electron environment in which they orbit. In this paper I shall outline the nature of this vulnerability and what the consequence of the loss of these satellites might be. As well, it is worth noting that large fluctuations in the geomagnetic field at auroral latitudes can induce electric currents in large power transmission grids sometimes causing them to be disabled for significant periods of time. I shall describe the nature of this problem and how space researchers are attempting to develop techniques to predict the potential for power outages. These practical manifestations will be presented in the context of the physical processes through which the solar corona interacts with the earth's magnetic field.
JSP23/W/00-B1 0910
REVEALING TEMPORARY MAGNETIC VARIATIONS ASSOCIATED WITH GEODYNAMIC PROCESSES
EPPELBAURN
Abstract not available at the time of going to press
JSP23/W/07-B1 0930
DESTRUCTIVE ATMOSPHERICALLY-GENERATED LONG WAVES: SEPARATION BETWEEN SOURCE AND TOPOGRAPHY
S. MONSERRAT (1), A.B. Rabinovich (2) and B. Casas (1). (1) Instituto Mediterráneo de Estudios Avanzados, IMEDEA, (CSIC-UIB), Palma de Mallorca, SPAIN, dfssmt4@ps.uib.es, (2) Tsunami Center, P.P. Shirshov Institute of Oceanology, Moscow, RUSSIA
Destructive long waves caused by atmospheric disturbances (meteotsunamis) present a significant threat for the Mediterranean coast, in particular, for the Iberian Peninsula and the Balearic Islands. Ciutadella Harbour, Menorca Island, is the place where extreme oscillations, locally known as 'rissaga waves', occur most frequently. The understanding of their origin and generation mechanism is a key scientific and applied problem. A method was first elaborated to suppress the influence of the initial source in order to isolate the general topographic function. The next step was to separate the resonant influence of the outer shelf from the local coastal features (bays or inlets). This second step allows reconstructing the corresponding admittance functions for any bay or inlet, which may be afterward used to predict amplification of meteotsunami but also of tsunami waves in a given location. The data of LAST-97 hydrophysical experiment (June-September, 1997) gave us a good opportunity to test this. A set of bottom pressure recorders were deployed on the shelf of Menorca Island, in two neighboring inlets of this island (Ciutadella and Platja Gran), and in Palma Bay (Mallorca Island); a number of precise microbarographs were working simultaneously. The first step of our analysis allowed reconstructing the open-sea source spectra for several abnormal seiche events recorded in the region of Ciutadella which, after compared with the observed atmospheric spectra, were used to estimate the so-called 'transfer function' between the atmosphere and the sea surface. This function is clearly related to the topography of the source area, but when computed for Ciutadella region, the transfer function was quite similar for different rissaga events suggesting consistency of the basic parameters (phase speed and direction of propagation) of the atmospheric waves generating large seiches. This fact can be used to predict the sea-level spectrum at a given location with the knowledge of the atmospheric pressure spectrum only. The second step of…
JSP23/L/05-B1 0950
ASSESSMENT OF GEOMAGNETIC HAZARD TO POWER SYSTEMS
D. H. BOTELER (Geomagnetic Laboratory, Geological Survey of Canada,Observatory Crescent, Ottawa, Ontario K1A 0Y3, Canada)
During severe geomagnetic disturbances electric currents induced in high voltage power transmission systems can cause transformer saturation resulting in transformer heating, generation of harmonics and increased reactive power demand. These effects can damage transformers, cause misoperation of protective relays and, in the worst case, cause power blackouts. An extensive study has been made to assess the geomagnetic hazard to power systems in Canada. Data from the Canadian Magnetic Observatory Network and conductivity models for different parts of Canada were used to calculate the electric fields produced during different levels of geomagnetic activity. This was combined with statistics on the occurrence of geomagnetic disturbances to determine the electric fields the power systems could expect to experience, on average, once a year and once every ten years. These electric field values were then used as input to power system models which calculated the corresponding levels of geomagnetically induced currents (GIC) in each power system.
JSP23/W/22-B1 1010
THE SATELLITE CONCEPTION FOR MONITORING OF IONOSPHERE EXCITATION BY SEISMIC OR TECTONIC PROCESSES.
Vladimir DOKUKIN, Victor Oraevsky, Yury Ruzhin and Vladimir Alekseev (IZMIRAN,Troitsk-town, Moscow Region, 142092, RUSSIA; E-mail: ruzhin@izmiran.rssi.ru )
The deep tectonic faults are known to be zones of concentration of stresses, canalisation of fluids, aerosols and gases, change of magnetisation and electro- conductivity of rocks, appearance of high electrical potentials and so on. Also the tectonic faults are associated with the geodynamical structures which form the zones of elevated seismicity (quakes or volcanic eruptions) or zones of dangerous natural hazards. The results of joint processing of the data of low-frequency emission, corpuscular flows as well as temperature and density of plasma permitted us to reveal the previously unknown effect of the generation of low frequency noises in space over the deep faults of the earth crust. The developing now in Russia method of ionosphere tomography also is very perspective for that .The system of the small satellites can be especially important for revealing and research of global and regional net of geological faults in an effort to plan searches of mineral resources and to forecast destructive earthquakes (volcanic eruptions). The first microsatellite COMPASS, weighting about 80 kg, is planned to launch to the circular orbit with height 400 km and inclination 790 for development of the methods of monitoring and forecasting of natural disasters on the base of co-ordinated monitoring at the Earth and from space the pre-earthquake phenomena. COMPASS is composed of several sensors associated to a data processing unit and a large memory in order to record the information all around the Earth independently from telemetry station. The details of the measurements, instruments and general conception of the microsatellite system based on the COMPASS mission are presented in the report.
JSP23/W/09-B1 1050
AIR QUALITY AS A GEOPHYSICAL HAZARD
Tom BEER (CSIRO Atmospheric Research, Aspendale, 3195, Australia, email:Tom.Beer@dar.csiro.au)
Geophysical hazards are usually considered to be earthquakes, volcanic eruptions, landslides, floods, droughts, tsunamis, storm surges, wildfire, tropical cyclones and extreme weather events. Air pollution is not normally considered to be a geophysical hazard. This view has arisen because the causes of air pollution – industrial and motor vehicle emissions – are not geophysical in nature. However, as air pollution regulations succeed in reducing the amount of pollutant emissions, air pollutant episodes become sporadic in nature, and their occurrence depends on a particular combination of meteorological factors. Analyses of air pollution episodes and hospital admissions indicate that there is a significant increase in morbidity and mortality as a result of air pollution episodes. Time-series studies undertaken in Sydney have shown that particulate matter, ozone and nitrogen dioxide are the pollutants that are primarily responsible for adverse health effects. Air quality forecasting systems can play an important role in mitigating the adverse effects of air pollution. The forecasts will affect the behaviour of susceptible individuals, and thus reduce adverse health effects. The outputs from forecasting systems can also be used to provide improved estimates of the total exposure to air pollutants of the inhabitants who are at risk. Such improved estimates can then be used in conjunction with longitudinal studies of health effects to obtain better understanding of the complex interaction between air quality and health. This presentation will illustrate the manner in which air pollution depends on meteorology, review some of the data concerning the resulting health effects, and discuss the future research needed for a better understanding of the interaction between air quality and human health.
JSP23/W/13-B1 1110
MULTIFRACTAL ANALYSIS OF TROPICAL ATMOSPHERIC STRUCTURES AND TYPHOONES GENERATION.
I. TCHIGUIRINSKAIA (E.E.&S. Dept., Clemson University, 342 Computer Court, Anderson, SC29625, USA, E-mail: iouliat@clemson.edu ); D. Schertzer (L.M.M., Université Pierre et Marie Curie, 4 Place Jussieu F-75252 Paris Cedex 05, France); S. Lovejoy (Physics Dept., McGill University, 3600 University st., Montréal, Qué., H3A 2T8, Canada)
During the last past ten years numerous investigations have been lead on the tropical atmospheric structures: boundary layer coherent structures, tropical storms and typhoons. Emphasis has been often placed on the structural conditions of generation of typhoons. Contrary to other approaches, we investigate this question on a large range of scales and intensities, trying to understand the crucial relationships between extremes events (such as typhoons) and more average ones, how the latter can build up to the appearance of the former. We chose thus a universal multi-fractal approach, since in this case the mean as well as the extreme events are ruled by three fundamental multi-fractal exponents determining the infinite hierarchy of singularities of the field and their corresponding co-dimensions. We analysed data sets obtained during two aircraft expeditions over South China Sea in 1988 and 1989 (Karmazin and Mikhailova, 1991). Measurements were usually done everyday from July to October on 8 or 11 levels from 50 meters up to 5 km heights, every 125 ms along 40 km in the horizontal for each level across the largest clouds bands. In the latter case, some flights were carried at a distance of Ed typhoon center as close as 7 km. Although variations of the estimates of the multi-fractal exponents are present, they do not seem to be significant, since these values remain close to those obtained in mid-latitude boundary layers or wind tunnel experiments (Schmitt et al. 1992). In conclusion, we discuss the rather low critical order of divergence of statistical moments qD=7 which rules the self organised criticality of extreme wind shears, temperature gradients and generation of related structures, in particular typhoons.
JSP23/W/32-B1 1130
LARGE-SCALE EVOLUTIONARY PROCESSES IN HAZARD SYSTEMS OF EARTHQUAKES, A PHENOMENOLOGICAL MODEL BASED UPON SELF-ORGANIZED CRITICALITY [SOC]
Natalia SMIRNOVA, Vladimir Troyan (both at Institute of Physics, University of St.Petersburg, St.Petersburg 198904, Russia, e-mail: nsmir@snoopy.phys.spbu.ru); Masashi Hayakawa (The University of Electro-Communications, Chofu, Tokyo 182, Japan,
e-mail: hayakawa@whistler.ee.uec.ac.jp); Thomas Peterson (TFPLAB, Cleveland, Ohio 44124-5441, U.S.A., e-mail: TFPLAB@aol.com); Yury Kopytenko (St.Petersburg Filial of IZMIRAN, St. Petersburg 191023, Russia, e-mail: galina@admin.izmi.ras.spb.ru)
The concept of self-organised criticality (SOC) is now widely used for the interpretation of the behaviour of natural hazard systems. This concept was recently introduced by the present authors as a way to search for earthquake precursory signatures. Here, we continue to consider earthquake region processes on the basis of the SOC concept. We suggest a phenomenological model for large-scale evolutionary processes that occur between violent earthquake episodes. Four principal stages of evolution are proposed and analyzed. They are: random chaos, subcritical, critical, and super-critical. External stimuli such as geomagnetic storms, sharp temporal and spatial variations in atmospheric pressure, and ULF impulses are considered as driving forces for a "cellular automata" process in active seismic regions. We discuss the possibility of using fractal characteristics of signals to study the critical dynamics of a hazard system. The important fingerprints of SOC - temporal and spatial fractal structures are analyzed using seismic and ULF electromagnetic data timed to violent earthquakes near Guam (August 8, 1993, M = 8.0) and Kobe (January, 16, 1995, M = 7.2). The research was supported by NASDA (Japan) and Russian Foundation for Basic Research (Grants No. 98-05-65554 and 99-05-NNN).
JSP23/W/10-B1 1150
ON CONNECTION BETWEEN THE SEISMICITY SPACE-TEMPORAL CHARACTERISTICS AND THE EARTH ROTATION
Boris W. LEVIN (*Shirshov Oceanology Institute of RAS and Russian Foundation for Basic Research, 32a Leninsky prosp., Moscow, 117334 Russia; levin@rfbr.ru)Yeugeny Chirkov (**Union Institute of the Earth Physics of RAS, 10 Bolshaja Gruzinskaja, Moscow, 123810 Russia; chirkov@uipe-ras.scgis.ru)
An importance of the Earth’s rotation influence to earthquakes occurrence was noted by I.Kant (1756), I.R.Mayer (1893), G.H.Darwin (1908) and was often discussed by geophysicists at present time. Supposing the unpredictability of natural hazards is connected partially with our poor understanding of the planetary processes role, we investigated a geographical distribution of the earthquakes. Using the catalog NEIC, we had created the histograms of the earthquake numbers and its energy as a function of a latitude F from 90 deg. N to 90 deg. S at period of 1900-1993. We had found that the latitude distribution of the event numbers N(F) is similar to the curve describing a dependence R^2(F) or I(F) where R is a distance from the axis of rotation and I is an inertia momentum of mass unit. Also we discovered the local maximum of the seismicity on so-called "critical latitude" 35 deg. N which was first mentioned by geographer A.Veronne (1912) and was calculated by F.Krasovsky and V.Magnitsky (1941) as a specific parallel for the Earth figure theory. The preliminary analysis of the seismicity-time dependence (more than 100000 events with M>4.0) for different latitude layers showed that the seismicity varies with main period of near 6 years practically at all latitude layers of the Earth.
JSP23/E/02-B1 1210
VOLCANIC RISK ASSESMENT AND ZONATION OF THE MAIN ERUPTIVE HAZARDS IN TENERIFE (CANARY ISLANDS)
Vicente ARAÑA and Alicia Felpeto (Dept. Volcanologia, Museo Nacional de Ciencias Naturales, Jose Gutierrez Abascal 2, 28006 Madrid, Spain); Mar Astiz (Dept. Matematica Aplicada, E.T.S. Arquitectura, U.P.M., Avda. Juan de Herrara, 4, 28040 Madrid, Spain, email: civgv@pinar1.csic.es);
Francisca Gomez (Centro di Studio per la Geologia Structturale e Dinamica dell´Apennino, CNR, Pisa Italy); Alicia Garcia and Ramon Ortiz (Dept.Volcanologia, Museo Nacional de Ciencias Naturales,
Jose Gutierrez Abascal 2, 28006 Madrid, Spain, email: mcngg92@pinar1.csic.es and mcnor72@pinar1.csic.es)
Taking into account that the island of Tenerife is a complex case, that one unique volcano and a unique eruptive style cannot be considered, the methodology developed in this paper to define a volcanic hazard-risk zonation in the island consists of: (1) Definition of the different hazards. (2) Numerical gradation of the probability of occurrence of each phenomenon by area. (3) Selection of the areas that show the higher probability of being emission centres. (4) Numerical simulation of the effects of an eruption of the corresponding eruptive style in those areas. The steps (1), (2) and (3) are based on the extensive knowledge of the eruptive activity of Tenerife Island and structural parameters. The results obtained from these three steps and the hazard map are implemented in a GIS and also used for the organisation of the surveillance network in terms of efficiency.
Monday 26 July PM
Presiding Chair: B Scott (GNA, CRI, New Zealand)
JSP23/W/80-B1 1400
STRESS CHANGES AT THE SOUTH ICELAND SEISMIC ZONE - A MODEL FROM 1706 UP TO THE PRESENT FOR BETTER HAZARD ESTIMATION
Frank ROTH (Section "Earthquakes & Volcanism", Division "Solid Earth Physics and Disaster Research", GeoForschungsZentrum, Telegrafenberg, D-14473 Potsdam, Fed. Rep. of Germany,
email: roth@gfz-potsdam.de)
The South Iceland Seismic Zone is situated between two sections of the mid-Atlantic ridge, i.e. the Reykjanes Ridge SW of Iceland and the Eastern Volcanic Zone on the island. It is a transform zone, though no typical one, as it is not connecting both rifts at right angles. Following this hypothesis, earthquakes should occur on EW-trending left-lateral shear faults, equivalent to conjugate, NS-oriented right-lateral, rupture planes. In fact earthquakes take place on NS-oriented faults, which are indicated by intensity and aftershock distributions, as well as by surface fault traces.
The stress field permanently generated in the fault zone by opening of the adjacent ridges with slightly more than 2 cm per year is computed and superimposed with the stress field changes induced by a series of 11 earthquakes (M >= 6) between 1706 and 1912. For these, different rupture depths are assumed, depending on the distance to the rifts. Finally, the post-seismic stress field of 1912 is extrapolated to the present, to see where highest stresses might have accumulated. In addition, the influence of loads at the Eastern Volcanic Zone on the stress field in the seismic area is studied.
The modelling shows that the stress is released by the series of events in the whole area, even though the ruptures planes are located on parallel NS-striking zones. The pre-seismic stress level for most events is high and pretty stable with the exception of situations when several strong shocks occur over a time span of several days, i.e. display typical main shock-aftershock patterns.
JSP23/C/U5/W/03-B1 1420
INITIAL STRUCTURES AND PACKING TRANSFORMATIONS OF LOESS DEPOSITS: IMPLICATIONS FOR THE ANALYSIS OF CATASTROPHIC MASS MOVEMENTS.
Eleanor PARKER and Tom Dijkstra (Coventry University)
Gradual settlement from aeolian suspension means that loess particles generally form very open initial packing. There is less than 50% solids in a unit volume of soil - unless there is too much water or additional stress which will cause particles to settle in a much denser state. As long as the deposit remains relatively dry, cementation and other bond types will maintain the open structure; the loess is metastable. The potential of metastable loess to collapse is impressive. Rapid transformations from undisturbed packing with dry densities of about 1.3 Mg/m3 (void ratio e ~ 1), to more closely packed 'deformed' fabrics with dry densities of about 1.65 Mg/m3 (e = 0.65) after collapse. At failure, signifcant pore volume reductions (often more than 10%) result in considerable rapid increases in pore pressures (principally related to water pressures, but in loess air pressures are also important). Such pore pressures are necessary ingredients to produce very mobile mass movements, usually in the form of flowslides. In situations where pore pressure dissipation is impaired, a lowering of the shearing resistance may last long enough to allow long run-outs and high sliding velocities. The study material is Chinese loess from Gansu province, but there are important parallels with similar collapsible deposits such as the brickearths of South East England.
JSP23/C/U5/E/04-B1 1440
EARTHQUAKES PREDICTABILITY: A CASE STUDY
Valery KOREPANOV, Yevhen Klymovych and Pavlo Maltsev (Lviv Centre of Institute of Space Research, 5-A Naukova str., 290601, Lviv, Ukraine, e-mail: vakor@isr.lviv.ua); Masashi Hayakawa (Dept. of Electronic Engineering, University of Electro-Communications, 1-5-1 Chofugaoka, Chofu, Tokyo 182-8585, Japan, e-mail: hayakawa@whistler.ee.uec.ac.jp); Katsumi Hattori (International Frontier Program on Earthquake Research, Institute of Physical and Chemical Research (RIKEN),
c/o Earthquake Prediction Research Center, Tokai University, 3-20-1, Orido, Shimizu 424, Japan,
e-mail: hattori@iord.u-tokai.ac.jp); Victor Tregubenko (Kyiv Branch of Ukrainian Geology Research Institute, 78 Avtozavodska str., 252144 Kyiv, Ukraine, e-mail: direct@kgou.ru.kiev.ua)
It is accepted that large earthquakes (EQ) are accompanied by different electromagnetic phenomena. They are also found to precede the EQ and the most debatable question is whether they can be used as EQ precursors. Two of such positive examples for EQ with M; 4,5 are investigated: near Matsushiro (Japan) 01.07.1998 and near Crimea peninsula (Ukraine) 16.10.1998. In both cases three components of magnetic fluctuations only were studied: for Matsushiro in frequency band from 0,01 to 30 Hz and for Crimea the DC magnetic field was sampled once per 10 seconds. For Matsushiro EQ some preceding events were extracted: short spikes with some features deviating from noisy background and also about 50% overall growth of daily averaged amplitude of ELF emission. For Crimea EQ the variations of mean longitudinal conductivity of the crust were calculated. The resulting curves excellently suit the Scholtz dilatant-diffusional model: for 15 days averaged variations of the conductivity defection from the mean value before earthquake was about 6% what was fairly beyond mean error ~ 1,2%. Still higher was the deflection for daily averaged variations: more than 25%. The peculiarities of the study and processing methodology are discussed.
JSP23/C/U5/L/01-B1 1500
MACRO SCALE MODELLING OF CATASTROPHIC NATURAL HAZARDS
Adrian STEWART, and Dr Claire McQueen, (EQE International Ltd, 500 Longbarn Boulevard, Warrington, WA2 0XF, UK. Tel:- +44 1925 838372, fax +44 121987 654, Email: astewart@eqe.co.uk, cmcqueen@eqe.co.uk.)
Economic losses from Natural disasters over the last few decades have been enormous, as demonstrated by Hurricane Andrew in the US. The impact on the Global economy can reverberate for years after a single event. Assessing the risk to regions and countries is essential in the context of enabling International Organisations, Governments a International Industry and Commerce to plan, mitigate and manage losses.
In terms of risk from damaging earthquake or windstorm events, the risk is a function of the hazard intensity combined with the vulnerability of the properties within any given unit or area. The deterministic results of such studies may also be combined With expected frequencies to obtain probabilistic estimates of risks. In order that the losses expected within an area from an event be estimated accurately, the vulnerability functions and hazard models should be representative of the scale of the are that they are located in. Scale is an important issue. The Hazard Model needs to reflect the reduced risks expected over larger areas. However, the detail needs to remain in order that the spatial resolution of the hazard across an area is accurately represented. The question is whether vulnerability and hazard models can be created for a specific scale, or whether it is possible to calculate losses on a detailed grid and aggregate consistently at any macro scale.
JSP23/W/39-B1 1520
SPACE PRECURSORS OF EARTHQUAKE REGISTERED BY SATTELLITE AT GEOMAGNETICALLY CONJUGATED AREAS
Yuri RUZHIN, Vera Larkina and Anna Depueva (IZMIRAN, Troitsk-town, Moscow Region, 142092, RUSSIA; email:ruzhin@izmiran.rssi.ru )
There is some progress in investigations of space plasma precursors of earthquake (EQ) - the magnetic conjugation of VLF pre-seismic emission on satellite orbits was found in both hemispheres. It means that some signature of precursor could be found inside the geomagnetic flux tube (shell) which connected with both conjugated ionosphere regions where the VLF precursors on satellite orbits were registered. Satellites INTERCOSMOS-18 and ALOUETTE data were analyzed from this point of view. Conjugated EQ-precursors are found in very low frequency (VLF) emission and ionosphere F2-layer plasma parameters. It should be pointed out that F2-precursors appears some days before the earthquake, manifest themselves as an plasma anomaly like Appleton anomaly if epicenter of future earthquake is situated near magnetic equator. It is shown that the electric field less than one mV/m have to be generated in the ionosphere. Then we’ll can be able to observe the above ionosphere phenomena as an equatorial earthquake forerunners. We are able to show that VLF precursors which appears some hours before the earthquake are localized close to magnetic shell corresponding to future earthquake epicenter and have a belt-like structure (longitude aligned on more than some tens thousands kilometers) in bot hemispheres. In the presented work relationship of VLF fields intensity and spectra with energetic electrons flux density are investigated over epicentral zone of the prone earthquake. On the base of our estimations and phenomenological development of the event in the ionosphere (plasmasphere) over the seismic region and over magnetically conjugated region the possibilities of the seismoionospheric anomalies (space precursors of EQ) generation are discussed.
JSP23/C/U5/W/10-B1 1600
THE CENTRAL POSITION OF GEOPHYSICS FOR THE EVALUATION OF THE NEAR-FUTURE AND ESPECIALLY THE DISTANT FUTURE
Nils-Axel MÖRNER, (Paleogeophysics & Geodynamics, S-10691 Stockholm, Sweden,
email: morner@pog.su.se)
Geophysics and its paleogeophysical expresions over past periods will always play a central role for all types of predictions and estimations of the future. This applies for the near-future and its evaluation based on our understanding of the natural variability in environmental parameters on a decadal-to-century time scale, and its interaction with induced anthropogenic factors. On the 104-105 year time scale, the selestrial mechanical calculation of the so-called Milankovitch variables form a strong basis in climate prediction. Distant predications and evaluations are, in general, neither simple nor straight-forward. Still, there is a desperate need for safity predictions over 104-106 year time scale when it concerns the long-term stability and safity of high-level nuclear waste repositories. This has added a completely new dimension to geophysics. For a "safe" final bedrock deposition of high-level nuclear waste, we need guarantees for the immense time period of "hundreds of thousands of years". No one can, of course, give meaningful guarantees over such long time periods. The Fennoscandian crystalline bedrock is, by no means, as stable and reliable as sometimes claimed. Only some 10,000 years back in time, the seismic activity was (as a function of the extreme rates uf glacial isostatic uplift amounting as much as some 10 cm per year) tremendously high; in amplitude as well as in frequency. In such an environment – to be repeated at the next future ice age – we can, of course, give no guarantees for a waste disposal in the bedrock; on the contrary, most facts suggest that it would be seriously damaged. In the absence of a true long-term safity, we can only propose that the waste produced: (1) is kept at a minimum, (2) is stored under constant control, and (3) is kept accessible for reparations as well as possible future innovations of how to render the waste harmless.
JSP23/E/14-B1 1620
LONG-TERM HAZARD FROM RIVER-BED AGGRADATION FOLLOWING
VOLCANIC ERUPTIONS
Thomas C. PIERSON (U.S. Geological Survey, Cascades Volcano Observatory, 5400 MacArthur Blvd., Vancouver, WA 98661, USA, email: tpierson@usgs.gov)
Explosive volcanic eruptions can provide immense volumes of readily erodible volcaniclastic sediment to drainage basins on or near source volcanoes. Posteruption rainfall, or other types of rapid runoff, mobilizes sediment from hillslopes or from source deposits in upper valleys, episodically moving it downstream during periods of high discharge (probably as long, slow- moving sediment waves). Depending on the volume of sediment added to a fluvial system, this sediment mobilization can result in dramatic and hazardous vertical aggradation of river beds. Data from recent historical eruptions at Mount Pinatubo (Philippines), Mount St. Helens (USA), and other volcanoes demonstrate that river-bed aggradation can occur rapidly (at varying rates as high as 0.4 m/day) in channels up to hundreds of meters wide over extensive downstream reaches in the first year or two following an eruption. Although periods of aggradation may be interrupted by irregular periods of degradation (channel downcutting), river-bed elevations may show net rises of as much as 20 to 30 m within only a matter of months within 50 km of source, and net aggradation of at least 8 m has been documented as far as 280 km from source. Under these conditions, floods and lahars need not have extraordinarily high discharges to be able to reach and inundate previously safe homes, roads, and farmland.
Aggradation may continue for decades before sediment supply from the disturbed areas decreases enough to allow rivers to incise back down to previous bed levels. Tree-ring data from terraces along the Sandy River, 80 km downstream from Mount Hood (USA) indicate that significant reincision (about 8 m or nearly 50 percent) occurred within about 40 years of the ~200 yBP eruption of Mount Hood, and the river nearly regained its original bed level within about 60 years. Efforts to mitigate river-bed aggradation hazards, such as has been done at Mount St. Helens, should be planned with knowledge of this potentially long-term impact on fluvial systems.
JSP23/C/U5/W/17-B1 1640
A SEA LEVEL-WAVE JOINT DISTRIBUTION FOR SEVERE STORM SURGE HAZARD ASSESSMENT USING OFFSHORE PLATFORM DATA
Le KENTANG (Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, PRC,
email: ktle@ms.qdio.ac.cn)
Generally speaking, the direct economic losses from a severe storm surge disaster consist mainly of that from sea water flooded over land and that from damage caused by high sea. However, the traditional method for storm surge hazard assessment in China is to construct one or two single-parameter distributions by using historical sea level and/or wave data at some coastal stations and/or ocean stations. In this case, apparently, both sea level data and wave data at these stations must be long enough to estimate the return periods needed for mitigation. However, the existing data of sea levels and waves at most of these stations can't meet the needs of the estimation. In this paper we presents a method to construct the sea level-wave joint distribution for severe storm surge hazard assessment by using a couple of years data on such a stations. Using a one-year platform data in the Bohai Sea, an example is given to illustrate the capabilities of this methodology.
JSP23/C/U5/E/08-B1 1700
STATISTICAL METHODS FOR SLUSHFLOW SITUATIONS RECOGNITION, MONITORING AND FORECASTING
Pavel CHERNOUSS and Olga Tyapkina (Center of AvalancheSafety,"Apatit" JSC, 33a, 50 years of October St.,Kirovsk, Murmanskregion184230, Russia, e-mail: P.Chernous@apatit.murmansk.su);
Erik Hestnes and Steinar Bakkehoi (both at NorwegianGeotechnicalInstitute, P.O. Box 3930 Ullewal Hageby, N-0806, Norway, e-mail: eh@ngi.no)
Slushflows - flowing mixtures of water and snow - are a hazardous phenomena in mountainous regions all over the world. They are most frequent in higher latitudes, i.e. in Norway, Iceland, USA(Alaska),Canada and Russia (northern and eastern parts). Slushflows exert high destructive forces and they are almost unpredictable due to inadequate studies. The work is an attempt to classify meteorological situations at different heights above sea level on "slushflow" and"non-slushflow" with linear discriminant analysis and Bayes'formula. Standard meteorological observations were used as primary parameters to describe the situations. Classification was made on daily base. Data for the mountain regions of Norway and the Khibini Mountains in Russia were taken to derive the classification rules and to carry out a verification of the methods. Different sets of parameters were tried to find out most informative ones. Two parameters have been chosen -daily water income (designed parameter) and snow cover thickness. Classification accuracy, obtained with independent data, was better than 75% for both types of the situations. For more detail slushflow danger monitoring one day moving average values are used. There are two ways to transform the diagnostic methods into forecast ones- by using of forecasted parameters as predictors or by extrapolation of situation probabilities. The methods are an effective tool for slushflow forecaster and realized as software package for the real-time work at the Center of Avalanche Safety of "Apatit" JSC.
JSP23/W/23-B1 1720
PRESEISMIC ELECTROMAGNETIC SIGNALS GENERATED IN ATMOSPHERE
Yuri RUZHIN (IZMIRAN, Moscow, 142092,RUSSIA; E-mail: ruzhin@izmiran.rssi.ru); Costas Nomicos (Technological Educational Institute of Athens, GREECE); Filippos Vallianatos (Technological Educational Institute Chania branch, Crete, GREECE)
Electromagnetic (EM) precursors of Earthquakes (EQ’s) are modern possibility to monitor pre-earthquake situation and to improve the EQ forecast. Its nature up to now is under the question. The EM signals registrated (before the EQ) onboard of satellites is the object of intensively investigations during last decade. Here we overview of EM seismo precursors and present situation with its explanation but the high frequency (HF) precursor (43MHz and 51MHz) is main point of our presentation. It is showed that precursor type HF signals are appeared before the EQ for one-three days and the some new peculiarity is found. This is under horizon epicenter position for main part of events under question. It means that emitted volume must be located at some altitude in atmosphere or ionosphere. The another unusual result is that such pre-seismic signals are responsible for seaquakes (not, as usually, for the earthquakes!). In result, we made conclusion about existing of some thunderstorm type activity above the sea level before the seismic event. It means that above sea level (up to 3-8 kilometers) the space charge cloud would be generated at one-three days before the active seismicity (under sea floor). Based on above mentioned we can supposed that probably this is new pre-seismic signature which will be used in future EQ forecast. Some additional experimental facts and mechanisms are discussed to explain this HF precursor (EM signals) generation above the epicenter of future seismic activity.
JSP23/W/87-B1 1740
SIMULATION OF THE DARWIN OBSERVATION OF THE 1835 CHILEAN EARTHQUAKE
GALIEV
Abstract not available at the time of going to press
Tuesday 27 July AM
Presiding Chair: Chen Yong (Seismological Bureau, CHINA)
Concurrent Poster Session
DETECTION, MONITORING, EARLY WARNING AND PREDICTION
JSP23/E/18-B2 0930
MONITORING THE CURRENT SUMMIT ERUPTION OF MOUNT ETNA USING INFRARED SATELLITE DATA FROM THE ERS ATSR-2
Rob WRIGHT, David Rothery, Stephen Blake (Department of Earth Sciences, The Open University, Milton Keynes MK7 6AA, UK, email: r.wright@open.ac.uk); Martin Wooster (Department of Geography, King's College London, Strand, London, WC2R 2LS, UK)
After the unusually quiet period that followed the end of the 1991 to 1993 eruptions, magmatic activity resumed within Etna's summit crater complex in July 1995. All four summit craters have been characterised by strombolian activity while between July 1997 and July 1998 the South East crater was also the site of sustained lava effusion. Intense paroxysmal explosions have also occured intermittently from the North East crater and La Voragine.
In March 1998, at the request of the Italian Civil Protection Authority, the European Space Agency commissioned the "Empedocles" project. This aim’s to assess the role that satellite remote sensing can play in monitoring the volcano, and understanding the nature and future evolution of the current activity. Using data acquired by the ERS-2 along Track Scanning Radiometer (ATSR) we show how the amount of short-wave infrared radiance emitted from the summit crater complex has fluctuated since July 1996. The data reveal patterns that correlate well (on a weekly time scale - ATSR acquires data ~ every 3 days) with Etna's general level of activity as documented in field reports. Examining the amount of radiation emitted at different wavelengths allows us to distinguish activity associated with high temperature vents from that associated with lava flows. By applying rank order statistics to the ATSR data-set we have inferred changes in the level of activity on Etna that may reflect changes in the eruptive state of the volcano.
JSP23/C/U5/W/07-B2 0950
THE SPACE VOLCANO OBSERVATORY (SVO) PROJECT
Pierre BRIOLE (Institut de Physique du Globe, 4 Place Jussieu, F-75005 Paris,
email: briole@ipgp.jussieu.fr) and the SVO science team
1500 volcanoes on the earth are potentially active. One third of them have been active during this century and about 70 are presently erupting. At the beginning of the third millennium, 10% of the world population will be living in areas directly threatened by volcanoes. Presently, in spite of the efforts of many countries, only a few volcanoes are monitored by modern observatories. Even in the best equipped of them, real-time data acquisition on the active parts of the edifices during crisis is an extremely difficult and risky task. The only way to provide global, continuous, real–time and all–weather information on volcanoes is to combine observations from space and from the ground. Spaceborne observations (with satellites, helicopters, drones, balloons,…) are mandatory and complement the ground ones that can be implemented on a limited set of volcanoes. A project called SVO (Space Volcano Observatory) has been proposed to the European Space Agency to remotely monitor the deformations and thermal changes of the highest active areas of the volcanoes (lava lakes, lava domes, lava flows, eruptive vents…). These zones are unstable and often deform significantly prior to paroxysmal events (sudden collapses, flank pyroclastic flows, …). They are also remote and dangerous and cannot be easily equipped with ground equipment. We propose to map at high resolution (1.5m pixel size) the topography and the thermal changes (for pixels above ~ 450°C) of active volcanic areas with a return time of one to three days and an image size of 6 x 6km. Those variations will put constraints on the physical and dynamic processes of the system. Other applications like landslide monitoring, will be possible. The requirement of fast data processing and interpretation imply the set up of several ground-based stations for data collection. The 12-15 major volcanological observatories of the world could host those receiving stations.
JSP23/E/42-B2 1010
VOLCANIC RISK AND EMERGENCY PLANS OF THE NEAPOLITAN VOLCANOES
Lucia CIVETTA (Co-ordinator of the thecnical committee for preparation of the emergency plans Osservatorio Vesuviano, via Manzoni, 249, 80123 Naples, Italy e-mail:civetta@osve.unina.it)
The volcanoes of the Neapolitan area, Vesuvius, Campi Flegrei and Ischia, have generated more than 100 explosive eruptions in the past 10 ka. However, they can lie dormant for many centuries and the great risk posed by volcanic activity in the region was, therefore, not always apparent. Vesuvius has exhibited various types of activity in the past 25 ka. Plinian and subplinian explosive eruptions occurred every few millennia or few centuries, respectively. Strombolian activity, lava effusions and phreatomagmatic eruptions usually follow the plinian and subplinian eruptions until conduit closes. Since the last eruption of 1944, Vesuvius has not shown signs of unrest. Only moderate seismicity and fumarolic emission testify the current state of activity of the volcano. The Vesuvius eruptive history however suggests that the longer is the quiescent period, the more violent is the renewal of the activity. The last eruption of the Campi Flegrei caldera occurred in 1538 AD, at the north-western edge of the. La Starza resurgent block. Since that time, after hundreds of years of subsidence, two bradyseismic events occurred in 1969-70 and 1982-84, which totalled a net vertical uplift of 350 cm of the central caldera block, at the harbour of Pozzuoli. The last eruption of Ischia occurred in 1302 AD, at the edge of the resurgent Mt. Epomeo block. Since that time intense fumarolic activity, hot springs and seismicity characterise the island current state. Intense urbanisation and inadequate planning of the Neapolitan territory have significantly contributed to the increment of the volcanic risk since the fifties. In response to the increasing volcanic risk, in 1993 the Minister for Civil Defence appointed a commission to prepare the emergency plan of the Vesuvian area that was completed at the end of 1995. In 1996 the Minister of Civil Defence appointed a new Commission to update the emergency plan of Vesuvius and prepare the scenario of the expected eruption at the Campi Flegrei Caldera and define the guidelines for the Campi Flegrei emergency plan.
JSP23/E/26-B2 1050
VOLCANIC HAZARD MAPS OF TENERIFE ISLAND (CANARY ISLANDS)
Alicia FELPETO , Vicente Araña (Dep. Volcanology, Museo Nal.Ciencias Naturales, CSIC, J. Gutiérrez Abascal, 2, 28006 Madrid, Spain, email: mcnaf66@pinar1.csic.es); Mar Astiz (Dep. Matametica Aplicada, ETSA, Universidad Politécnica, Avda. Juan de Herrera 4, 28040 Madrid, Spain); Francisca Gómez (Centro di Studio per la Geologia Structturale e Dinamica dell'Apennino, CNR, via Santa Maria, Pisa, Italy); Alicia García , Ramón Ortiz (Dep. Volcanology, Museo Nal. Ciencias Naturales, CSIC, J. Gutiérrez Abascal 2, 28006 Madrid, Spain)
The first steps for the generation of volcanic hazard maps of Tenerife consists of the definition of the most significant hazards and the selection of the most suitable areas for containing emission centres, taking into account all the data of the eruptive history of the island. Then, for the evaluation of the effects of an eruption, a numerical model for each hazard has been chosen. The application of the different models allows the computation of the probability of each point of the island being affected by each type of eruption, and so, building up the volcanic hazard maps. The methodology proposed, integrated on a GIS framework, allows the automation of the generation of hazard maps for more specific studies of smaller areas of the island or specific risk scenarios. It also represents the starting point for developing risk maps.
JSP23/C/U5/E/20-B2 1110
MAPPING AND MONITORING OF VOLCANOES USING SPACE-BORNE SAR
Woolil M. MOON, Lanying Feng and (Geophysics, The University of Manitoba, Winnipeg,Canada R3T 2N2 (email: lfeng@gis.geop.umanitoba.ca, wmoon@cc.umanitoba.ca); DUK-JIN>KIM , K.H. Choi, C.W. Lee and Woolil M. MOON (Earth System Science, Seoul National University
(email: wmoon@eos1.snu.ac.kr, djkim@eos1.snu.ac.kr); J. L. Lizeca (SERGEOMIN, La Paz, Bolivia ( "Jose Liuseca "abtema@coord.rds.org.bo
In this study, we have investigated several active volcanic areas (Baiktu-san (China-Korea border), Cerro Caquella (Bolivia), and Halla-san (South Korea)) using RADARSAT and JERS-1 SAR data for their geological characteristics and for their application criteria in view of natural hazard monitoring. Baiktusan is located at the junction of northeastern edge of Huabai tectonic block of the Eurasian continent and mid-Cenozoic off-shore Pacific volcanic zone, and have gone through several stages of crustal evolution. According to historical records, Baiktusan had a major eruption in 1002 AD, and several minor eruptions in 16th and 18th century. However, the strategic location of Baiktusan at the political boundary between P. R. China and North Korea, has resulted in a situation with rather poorly surveyed geology maps and inconsistent geological interpretation of recent volcanic activities. The Halla-san volcano has not been active during the histrocial time, but it is the main feature of the Jeju Island (a volcanic island), which has recently been rapidly developed for increasing human settlement. In the Cerro Caquella region, which is a remote barren Andean range, a detailed DEM could be extracted to investigate morphological changes associated with active volcanic activities, in addition to correlation of the DEM with respect to several other geological and geophysical data collected over the study area. Several sets of JERS-1 SAR and RADARSAT data are acquired for this study with the objectives of investigating the surface geology of Baiktu-san and Halla-san volcanoes and the surrounding area to delineate consistent geological and volcanic characteristics. Both traditional geological remote sensing approach and the space-borne InSAR (SAR interferometry) approach were used (i) for structural geological interpretation of the study area using the pre-processed SAR data, and (ii) for correlation of the interferogram fringe pattern…
JSP23/C/U5/W/02-B2 1130
THE MONTSERRAT VOLCANO ALERT AND WARNING SYSTEM
Lloyd L. LYNCH (Seismic Research Unit, University of the West Indies, St. Augustine, Trinidad W.I., email: sru@wow.net)
From the onset of the Soufriere Hills volcano eruption on July 18, 1995, to the waning stages of the eruption almost three years later most areas of the more developed half of the island of Montserrat faced the threat of devastation. The relatively small size of the island, its complex political and governance structure, and the demographic setting in relationship to the threatening volcano were factors which all combined to make the management of the crisis one of the most challenging of the twentieth century. Compounding matters, was the fact that the eruption followed a style for which there was no well-documented precedent. As in most volcanic crises, an alert and warning system was instituted primarily to facilitate risk and emergency management. The system employed was an adoption of the generic alert and warning system popularised by the UN Volcanic Emergency Handbook. In this article the Montserrat volcano alert and warning system is modelled as network of closely interrelated functional entities comprising of a management subsystem, a detection subsystem and a response subsystem. This provides a comprehensive abstraction of the functions and interaction between the administrative authorities, scientists and the public during the eruption. With aid of this model a detailed analysis of the strengths and shortcomings of the system is performed and presented. Attempt is also made to document the major changes within the subsystems during the crisis. There were several. Among the most remarkable were the many changes in the management personnel such as chief minister, governor and chief scientists. Throughout the crisis key institutions such as the Montserrat Volcano Observatory and the Emergency Operation Center also endured constant evolution. Operational and decision-making policies and procedures within these institutions encountered numerous revisions. Generally, these changes were intended to facilitate the tacit objective of local authorities to maximise life safety while retaining a sustainable level of functionality on the island. In the absence of…
JSP23/W/24-B2 1150
A DEVELOPING VOLCANIC CRISIS IN DOMINICA, LESSER ANTILLES
John B. SHEPHERD, Lloyd L. Lynch, Mark Stasiuk, Joan L. Latchman (Seismic Research Unit, UWI, St. Augustine, Trinidad, e-mail: johnbshepherd@hotmail.com); Joseph M. Devine (Brown University, Providence, R.I. USA)
The island of Dominica is in the centre of the volcanically active Lesser Antilles island arc. The island is approximately 35 km long by 12 km wide and is composed entirely of Pleistocene to recent volcanoes. Earthquake swarms have been reported from Dominica since it was first settled by Europeans. These originate in all parts of the island but are most common in the southwestern part of the island where there are at least three volcanic vents which have erupted in the last few thousand years.
The most recent swarm began in September 1998 and is continuing. By January 10 1999 over 1,000 shallow volcanic earthquakes had been recorded by a nine-station digitally recording short period seismograph network. Over 300 earthquakes had been felt in the southwestern part of Dominica causing significant damage. Epicentres were initially located close to Morne Plat Pays volcano but during the swarm have spread to the most of the southwestern region. Focal depth are in the range 1-5 km and are becoming shallower as the swarm progresses. GPS measurements have detected widespread inflation of the epicentral region. An extensive programme of geological mapping is in progress and a response plan has been developed by the civil authorities.
JSP23/C/U5/W/14-B2 1210
THE SEISMIC ALERT SYSTEM IN MEXICO CITY AND THE SCHOOL
PREVENTION PROGRAM
ESPINOSA ARANDA J M, A Jimenez, G Ibarrola, F Alcantar, A Aguilar, M Inostroza, S Maldonado Director, (Centro de Instrumentacion y Registro Sismico, A.C. Anaxagoras #814, C.P. 03020, Mexico, D.F. E-mail: cires@cires.org.mx Home page: http://www.cires.org.mx; ); R Higareda (Director, Direccion de Emergencia Escolar Subsecretaria de Servicios Educativos del Distrito Federal Secretaria de Educacion Publica Callejon de Torresco #12, C.P. 04010, Mexico, D.F. E-mail: rhigareda@yahoo.com)
The Seismic Alert System (SAS) is a public service developed with the sponsorship of the City Government Authorities, with the aim to mitigate seismic disasters. Since August, 1991, after 88 months of continuous operation, the SAS has being capable to detect 714 seismic events in the Guerrero Coast; 12 of them so strong to trigger general alerts in Mexico City, 34 restricted, and one false general alert. The warning ranges strong or restricted correspond to seismic magnitude forecasted great than 6, or great than 5. During the "Copala" M7.3 earthquake, in September 14, 1995 the SAS was activated and issued a general warning signal in Mexico City, 72 seconds prior to the ``S'' ground motion first arrivals. This earthquake warning reached an estimated population of more than 4 million citizens. The response of children in schools was massive because of the application of an earthquake hazard reduction program. The Copala earthquake helped us to identify the societal response strengths and weaknesses to the earthquake early warning signal. The long-term plan of hazard mitigation of the National Ministry of Public Education, Secretaria de Educacion Publica (SEP), has created awareness to earthquakes in the children that have assisted in these years to various school levels. Even though they did not suffered the disastrous consequences of the 1985 earthquake, they are more aware than the average people that lived through that disastrous event, who still are not trained.
Tuesday 27 July PM
Presiding Chair: J M Espinosa-Aranda
(Centro de instrumentacion y Registro Sismico, Mexico)
JSP23/W/12-B2 1400
SEASONAL WARNING FOR CLIMATIC HAZARDS: PROSPECTS AND RESPONSES
T.DOWNING (Environmental Change Unit, 1A Mansfield Road, Oxford, OX1 3TB,
Email: tom.downing@ecu.ox.ac.uk)
With climate change, there is increasing concern that climatic hazards will become more frequent and more severe. One of the most promising developments is seasonal climate forecasts. Already forecasts are operational in many parts of the tropics and sub-tropics, and particularly for droughts and floods associated with ENSO events. Prospects for further development of seasonal forecasting for a range of climatic hazards are reviewed, illustrated with case studies in Africa and Europe. A critical evaluation of the utility of seasonal forecasts centres on vulnerability, communication channels, and effective responses. In contrast to short-term prediction, seasonal forecasts raise new issues of preparedness and the use of information.
JSP23/E/10-B2 1420
CHANCES FOR A LONG TIME FORECAST OF SEVERE STORM EVENTS IN WESTERN EUROPE WITH RESEPCT TO THE NORTH ATLANTIC OSCILLATION
Mattius KLAWA, Uwe Ulbrich and Johannes Wefers (Institut fuer Geopyhsik und Meteorologie, Kerpener Str. 13, 50923 Koeln, Germany, e-mail: mklawa@meteo.uni-koeln.de, phone: 49 (0)221/470-3689)
The North Atlantic Oscillation is the dominant variability pattern in sea level pressure over the North Atlantic. Spectral analyses of the variations of this pattern show peaks on seasonal, yearly or decadal time scales. Also research proved influence of the NAO on the North Atlantic Stormtracks and on the European climate e.g. rainfall rates, winter temperatures in western Europe. In this presentation extreme storm events in western Europe are evaluated with respect to the NAO. Probabilities for extreme storm events on time scales of 5-10 years dependent on the NAO are estimated. In combination with daily weather regimes (since 1881) the long time series of the NAO pattern (since 1865) is used for a more detailed analyses on European weather events. In a first step damaging storms named by reinsurance companies and meteorological extreme events are compared. Weather regimes associated with these events are used for a description for the atmospheric circulation over Europe and to find out common features of periods around storm events. In a final step the probabilities for storm events are evaluated and interpreted.
JSP23/E/29-B2 1440
FRACTURE CRITICALITY: A NEW CRITERIA FOR MONITORING THE ONSET OF EARTHQUAKES AND FRACTURING
Stuart CRAMPIN (Department of Geology & Geophysics, University of Edinburgh, Edinburgh EH9 3JW, UK; email: scrampin@ed.ac.uk)
Seismic shear-wave splitting, diagnostic of distributions of stress-aligned fluid-saturated grain-boundary cracks and low aspect-ratio pores is seen with very similar characteristics in almost all igneous, metamorphic, and sedimentary rocks with a few well-understood exceptions. There is a minimum shear-wave velocity anisotropy of about 1.5% and a maximum of about 4.5% in intact un-fractured rock below about 1km in the crust. Theory and both field and laboratory observations suggest that this maximum value is close to the level of fracture criticality, associated with the percolation threshold, where rocks are so heavily fractured that shear-strength is lost, through-going fractures propagate, pore-fluids disperse, and earthquakes and fracturing occur. The evolution of such fluid-saturated rock can be modelled with anisotropic poro-elasticity (APE), where the driving mechanism is fluid migration by flow or diffusion along pressure gradient between neighbouring grain-boundary cracks and pores at different orientations to the stress field. APE shows that shear-wave splitting is controlled by the same parameters as control pre-fracturing deformation so that shear-wave splitting can be used to monitor directly the approach of fracture criticality before earthquakes or other failures by fracturing. The high seismicity of SW Iceland and the extensive SIL seismic network now allow changes in shear-wave splitting before earthquakes to be observed routinely with hindsight. A real-time "stress-forecast" in a narrow magnitude/time window was made with forecasts 17, 15, and 3 days before a M=5 earthquake on 13 November 1998. The key feature is monitoring the increase of stress in the relatively-undisturbed rockmass away from the complications of the earthquake source, and estimating the time at which induced cracking reaches the level of fracture criticality. By monitoring the build-up of stress, such stress-forecasts can give (potentially reliable) estimates of time and magnitude of future earthquakes but cannot give estimates of location. However, forecasts may well stimulate local studies, as was the case in Iceland, where investigations by the Icelandic Meteorological Office correctly identified the rupturing fault.
JSP23/W/01-B2 1500
THE COASTAL OCEAN MONITORING AND PREDICTION SYSTEM FOR WEST FLORIDA
MARK E. LUTHER, David Burwell, Meredith Haines, Nan Schmidt, Mark Vincent, Robert Weisberg, and Huijun Yang (University of South Florida Department of Marine Science, 140 Seventh Avenue South, St. Petersburg, FL 33701; Tel: 727/553-1528; Fax: 727/553-1189; E-mail: luther@marine.usf.edu)
Florida is the United States’ fourth most populous state, with 80% of the population living in a coastal county. Several recent storms have brought large, unpredicted flooding to Florida’s west coast. The coastal sea level response to tropical and extra-tropical storms results from wind forcing over the entire continental shelf. Much of the local response may actually be due to storm winds quite distant from the local area of concern; a case in point being tropical storm Josephine, a modest storm that nevertheless caused extensive flooding in the Tampa Bay area. The University of South Florida is implementing a real-time Coastal Ocean Monitoring and Prediction System (COMPS) for West Florida that will provide additonal data needed to give more accurate predictions of ocean storms and coastal flooding by storm surge. This system consists of an array of instrumentation both along the coast and offshore combined with numerical circulation models and builds upon existing in-situ measurements and modelling programs funded by various state and federal agencies. This observing system fulfils all of the requirements of the Coastal Module of the Global Ocean Observing System (CMGOOS). Data and model products are disseminated in real-time to federal, state, and local emergency management officials via the internet (URL http://comps.marine.usf.edu).
JSP23/W/03-B2 1520
EARTHQUAKE PREDICTION AND EARTHQUAKE PREPAREDNESS: CURRENT POSSIBILITIES FOR THE PACIFIC RIM.
Vladimir KOSSOBOKOV, Vladimir Keilis-Borok, (International Institute for Earthquake Prediction Theory and Mathematical Geophysics, Russian Academy of Sciences, 79-2 Warshavskoye Shosse, Moscow 113556, Russia, E-mail: volodya@mitp.ru); John Healy (USGS, Menlo Park, CA 94025, USA, E-mail: jhhealy@aol.com); Donald Turcotte (Department of Geological Sciences Cornell University, Ithaca, NY 14853-1504, USA, E-mail: Turcotte@Geology.Cornell.edu)
The recent results of real-time testing in the Pacific Rim, 1992-1998, have established the high statistical significance of intermediate-term predictions of the largest earthquakes by algorithms M8 and MSc. Among predicted are all earthquakes of magnitude 8 or greater. Predictions are completely reproducible and use precursory activation of seismic static at different space and time ranges to reduce consecutively time and space where disastrous earthquake has to be expected. Although the predictions are of limited accuracy they do create a possibility to prevent part of the damage. This encourages a multi-scale approach to mitigate earthquake disaster. In general, earthquake predictions range from a zero-approximation of seismic zoning through long- and intermediate- to short-term ones. Accordingly, the preparedness measures range from building code, to simulation alarms and reinforcement of high-risk facilities, to the imminent "red alert" (e.g. evacuation of population and introduction of martial law). Different time from decades to seconds is required to undertake different measures; having different cost, they can be realistically maintained during different time periods and in the territories of different size. The key to damage reduction in the area of concern is escalation or de-escalation of preparedness measures depending on the current state of alert. That is the standard practice for mitigation of other major disasters, wars included. The interface between prediction and preparedness is delivered by the recent development of optimal strategies based on a trade-off between total volume of alert and rate of failures-to-predict. We demonstrate case histories of intermediate-term predictions that would have led to preventing a considerable part of losses by low-key safety measures.
JSP23/E/06-B2 1600
SANARIS PROJECT: A SATELLITE NETWORK FOR NATURAL RISKS MONITORING
Marta TARRAGA (Dept. Volcanologia, Museo Nacional de Ciencias Naturales, Jose Gutierrez Abascal 2, 28006 Madrid, Spain, email: mcnt184@mncn.csic.es); Alicia Garcia, Ramon Ortiz, Rafael Abella and Javier Peña (Dept. Volcanologia, Museo Nacional de Ciencias Naturales, Jose Gutierrez Abascal 2, 28006 Madrid, Spain, email: mcnp182@mncn.csic.es)
A new satellite communication system specifically designed for low-rate data applications has been developed and prototyped. A validation project is proposed to install a pilot network to be operated during 6 months. One of the target markets related to volcanoes has been selected, so a group of users is integrated in the project. A specific application for this market will be developed regarding data acquisition, processing, storage and dissemination to distant users. The feasibility of using the new satellite system to provide a new Eutelsat service for low-rate data applications will be evaluated from the pilot network performance. According to the Department of Volcanology (M.N.C.N.-C.S.I.C.) experience on the development of systems for volcano monitoring, its role in the project will be: -Co-ordinate the definition of users requirements for the pilot application. Installation of the digital seismic stations. –Maintenance of Teide and/or Timanfaya stations (Canary Islands).
JSP23/C/U5/E/06-B2 1620
EFFECTIVE EARTHQUAKE MONITORING PROCESS FOR EMERGENCY RESPONSE ON RESCUES (EMPEROR)
Yutaka NAKAMURA (System and Data Research Co. Ltd., SDR Bldg., 3-25-3 Fujimidai, Kunitachi-shi, Tokyo, 186-0003, JAPAN, E-mail: yutaka@sdr.co.jp)
It has been widely recognised that systematical and continuous monitoring of earthquakes is necessary for the early warning. In this presentation an effective earthquake monitoring process is proposed. DI, Damage Intensity of seismic motion, is defined as an inner product of acceleration vector and velocity vector at each time step dt. The multiplication of DI with mass received seismic motion, indicate the power of the motion act to the object. DI-value, defined as maximum of DI, is generally appeared after S-wave arrival. When P wave arrives, DI increases drastically, and after S wave arrival DI reaches to its maximum value, DI-value, soon. P wave Index, PI-value, is defined as maximum DI of P wave part. This value is suggested to be used for P wave alarm. DI-value is related with seismic intensity. DI-value has a very important practical advantage, since it can be calculated in real-time soon after the P wave arrives. Additionally, DI-value has a clear physical meaning and it is strongly related with the earthquake damage. This can be concluded as, with the continuous observation of DI, earthquake alarm can be issued efficiently and damage can be estimated precisely. According to combination of S wave and P wave alarms, early and/or reliable alarm is realised. P wave alarms can be issued when PI-value over the pre-set level, and S wave alarm can be issued when ordinary monitored values or DI-value exceed pre-set level. Combining PI, DI values together with K values is promising for the future early warning systems, since it has been clarified with both methods that it is possible to estimate the vulnerabilities of all ground and structures concerned and it is possible to issue the alarm before the real damage occurs.
JSP23/W/06-B2 1640
HIGH RESOLUTION AEROMAGNETIC SURVEY FOR CONCEALED FAULTS IN THE FUKUI PLAIN, CENTRAL JAPAN
Shigeo OKUMA, Masahiko Makino and Tadashi Nakatsuka (Geological Survey of Japan, 1-1-3 Higashi, Tsukuba, Ibaraki, 305-8567 Japan, email: okuma@gsj.go.jp)
Geological Survey of Japan (GSJ) has conducted a helicopter-borne high-resolution aeromagnetic survey in the Fukui Plain, Central Japan, to better understand concealed faults associated with the 1948 Fukui Earthquake (June 28, 1948, M=7.3) which brought disastrous damages to this area. The survey was flown along east-west flight lines at an altitude of 150 m above terrain and spaced 300 m apart with a Cesium Vapour magnetometer with a sensitivity of 0.01 nT at a sampling interval of 0.1 second and a differential GPS system. The compiled total intensity map of IGRF residuals shows interesting magnetic features as follows: 1) A broad magnetic high area occupies the western half of the plain with a sharp NNW-SSE trending boundary to the east, which corresponds well to the assumed location of the concealed Fukui Earthquake fault. 2) Three distinctive dipole magnetic anomalies lie in the magnetic high area, two of which lie at the northern edge of the area, implying the existence of intrusions associated with the Awara Hot Spring. 3) Magnetic lows are dominant along the coast line of the Sea of Japan and in its offshore areas, suggesting the existence of reversely magnetised volcanic rocks which lie offshore and maybe outcrop along the coast line.
JSP23/E/27-B2 1700
LAND SUBSIDENCE OF JAKARTA (INDONESIA) AND ITS GEODETIC-BASED MONITORING SYSTEM
Hasanuddin Z. ABIDIN , I. Meilano, M. A. Kusuma , J. Kahar (Department of Geodetic Engineering, Institute of Technology Bandung, Jl. Ganesha 10, Bandung, Indonesia, email: hzabidin@indo.net.id and hzabidin@gd.itb.ac.id); Rochman Djaja (National Coordinating Agency for Survey and Mapping, Cibinong, Bogor, Indonesia); Samsul Hadi (Jakarta Provincial Agency of Surveying and Mapping, Jakarta, Indonesia)
Jakarta is the capital city of Indonesia with population of about 12 million peoples, inhabiting the area of about 25-km by 25-km. It has been reported for quite sometimes that several places in Jakarta are subsiding at different rates from place to place. Up to the present times, however, there has been no definitive, detail, and comprehensive information about the characteristics and pattern of land subsidence in Jakarta areas. Usually the land subsidence in several places of Jakarta is estimated using their geological parameters or inferred from the ground water level observations. In order to give a better picture about these land subsidence phenomena in Jakarta, the geodetic-based land subsidence monitoring system has been implemented. The system is based on GPS and levelling measurements.
In this paper the land subsidence study in the city of Jakarta using repeated GPS and levelling surveys will be described and discussed. The land subsidence characteristics of Jakarta and its surrounding area are investigated using the data from three repeated GPS surveys conducted in 1994, 1997, and 1998 and four repeated levelling surveys performed in 1982, 1991, 1993, and 1997. The main goal of this land subsidence study is to understand the characteristics of land subsidence in Jakarta area and their generating forces and factors. Therefore, in this paper, the geological, geophysical, and hydrological aspects of Jakarta area would also be investigated and correlated with the geometrical changes information obtained from geodetic based systems. The paper would be sum up with some closing remarks.
JSP23/W/38-B2 1720
INTERNATIONAL TECTONIC REAL TIME RADON OBSERVATION AND TRANSMISSION - RELIMINARY RESULTS OF GEODYNAMIC MONITORING.
G.SOBOLEV (United Institute of Physics of the Earth, RAS, Moscow, Russia,
email: sobolev@uipe-ras.scgis.ru); S.Balassanian (National Survey for Seismic Protection, Yerevan, Armenia, email: presidnt@nssp.yerphi.am); A.Belayev (Vernadsky Institute of geochemistry and analytical chemistry, RAS, Moscow, email: abelyaev@chat.ru); S.Bushati (Center of Geophysical and Geochemical Exploration, Tirana, Albania, email: bushati@cgge.tirana.al); E.Lagios (Department of Geophysics and Geothermy, National & Kapodistrian University of Athens, Athens, Greece,
email: elagios@atlas.uoa.gr); R.A.Nicholson (British Geological Survey, Keyworth, Nottinghamshire, NG125GG, United Kingdom, email: RAN@wpo.nerc.ac.uk); A.Ponomarev (United Institute of Physics of the Earth, Moscow, email: avp@uipe-ras.scgis.ru); A.Pronin (Geological-technological Scientific Inductional Enterprise "Geotechvims", Naro-Fominsk, Russia); G.Sideris, F.Zervos (GeoMentor, European Economic Interest Grouping, Athens, Greece, email: geomen@otenet.gr).
Seismic activity is a potential threat to populations and commerce throughout the world. Geophysical-geological research institutes and commercial companies in Greece, France and the UK are collaborating with similar organisations from Russia, Armenia and Albania, under the EU-funded Inco-Copernicus (Framework IV) programme, to develop new techniques for the automatic acquisition of gas geochemical data from remote sites using gas-sensing probes and telemetry. The data are being integrated with seismic information acquired in parallel, and used to determine whether or not the technique is a suitable method for monitoring ground disturbance associated with tectonic events.A number of data loggers (transducers/detectors) have already been installed since 1998 at specific locations (base stations) selected by the Project scientists in Caucasus (Southern Russia and Armenia), Greece, Albania and Scotland (UK). The seismic and gas-hydrogeochemical maps as the results of geophysical prospecting were used to select eligible sites for radon monitoring. Each base station includes two data loggers with the latest version of the Barasol MC radon probe incorporating sensors for barometric pressure and temperature combined with local rainfall measurements. These parameters are being transferred to attached cordless modems and are transmitted via INMARSAT global satellite communication system to Greece (Project co-ordinator) where all data are collected for joint processing. Signal processing software has been developed on the base of standard and original approaches. The spectral composition and structure parameters of obtained time series are determined by applying descriptive statistics, causal analysis and methods of the dynamic theory systems. The first stage realisation of Project indicates that telemetry systems are operating satisfactorily and the data are collecting, but that longer-term monitoring is necessary to link seismic measurements to radon exhalations and consider mentioned data acquisition-broadcasting system as real warning system.
JSP23/C/U3/W/21-B2 1740
DEVELOPMENT OF SEISMIC RAPID REPORTING AND EARLY WARNING SYSTEM IN TAIWAN
Yih-Min WU, Jen-Kuang Chung, Tzay-Chyn Shin (Central Weather Bureau, 64 Kung Yuan Road, Taipei, Taiwan, email: ludan@ss2.cwb.gov.tw); Yi- Ben Tsai (Institute of Geophysics, National Central University, Chung-li, Taiwan); William H.K. Lee (862 Richardson Court, Palo Alto, CA 94303, USA)
In 1994, two prototype seismic early warning systems have been implemented in Taiwan: (1) a rapid reporting system using a tele-metered network of digital accelerographs spread over the entire island, and (2) an alert system exploring the use of modern technology for the highly seismic area of Hualien. After four-years operation, the rapid reporting system was successfully operated in the seismic monitoring system of the Central Weather Bureau (CWB) for felt earthquake observation (Taiwan Rapid Earthquake Information Release System, TREIRS). It has achieved in the determined of precise earthquake location and magnitude computation about in one minute after the earthquake origin times. On the other hand, the Hualien alert system was phased out in 1998 due to large uncertainty of source parameters determination caused by small station coverage and only using P signal in determining the magnitude. Although it performed a very well reporting time (less than 10s after the earthquake origin time). Recently, the Hualien alert system stations were equipped with the digital accelerograph and combined to the TREIRS system. By adding the Hualien alert system stations to the TREIRS system, we have obtained a good precision for source parameter determination and a well reporting time for Hualien area earthquake monitoring. During the experiment in the past several years, we benefited from these two prototype seismic early warning systems and optimised the TREIRS system. We are encouraged forwards in the development of seismic early warning system based on the successful experience
Friday 23 July AM
HAZARD AND RISK ASSESSMENT, RISK MITIGATION AND
MANAGEMENT
JSP23/W/30-A5 Poster 0830-01
MISLEADING SIGNALS IN HAZARD CATALOGS
Allen M. HITTELMAN (NOAA's National Geophysical Data Center (NGDC), World Data Center-A (WDC-A for Solid Earth Geophysics, 325 Broadway, Boulder, CO 80303, U. S. A.,
email: ahittelman@ngdc.noaa.gov); Lowell S. Whiteside and James F. Lander (Co-operative Institute of Research in Environmental Sciences, NOAA, 325 Broadway, Boulder, CO 80303, U. S. A.,
email: lws@ngdc.noaa.gov)
The primary purpose of natural hazard data catalogs is in the mitigation of future disasters. It is hoped that future natural disasters can be anticipated and populations warned if long term catalogs, which record the regional periodicity of events, are available. While such long-term variations in hazard are possible, we show that many current catalogs of natural hazard data may not be satisfactory to determine whether they actually occur.
Most hazard catalogs cover periods of less than 200 years and are reasonably complete and accurate for only the past 20-50 years. Such catalogs are not sufficient to investigate long term hazard variations. Earthquake, tsunami and volcanic catalogs, acquired and integrated at NGDC, illustrate artificial long-term variations created by cultural and scientific reporting changes, which can introduce unanticipated cyclical variations in the catalogs. These inconsistencies are often related to changes in the way magnitudes are calculated, evolving network equipment, network discontinuities of operation and personnel.
JSP23/W/35-A5 Poster 0830-02
DISASTERS CAUSED BY CATASTROPHIC STORMS AND THEIR PREVENTION IN SMALL CATCHMENTS IN THE QIN MOUNTAINS
Guozhang FENG (College of Water Resources and Architectural Engineering, Northwestern Agricultural University, Yangling, Shaanxi, 712100, China, e-mail: gfeng@public.xa.sn.cn)
Catastrophic storms often cause flash floods and corresponding geophysical hazards in the Qin Mountains in Shaanxi Province, China. The disasters are difficult to be prevented due to their rare occurrence, extremely high severity, non-predictability and too short warning time. The 980709 storm, occurred in a small area in the southeast of the Qin Mountains on 9 July 1998, is the maximum storm event in the records in the region and has an investigated maximum point storm rainfall of approximately 2122 mm during 6 hours and 40 minuets at one of two storm centers, and 1511 mm during 11 hours and 30 minutes at another center. The areas involved inside the isohyets of 1500 mm, 1000 mm, 500 mm and 50 mm’s storm rain, are 31.4 km2, 45.5 km2, 86.8 km2 and 847.1 km2, respectively. The storm formed enormous flash floods, landslides, mud-rock flows and aggradation of the riverbeds. As a combined consequence of the storm related disasters, 82 people and over 2000 thousands livestock were lost, over one hundred families were homeless, and most of the farmlands with growing crops were destroyed in the disaster involved two small catchments, especially in their densely populated valleys. Similar disasters with relatively lower severity frequently occur in the Qin Mountains even during the periods of general storms.
Reconstruction and protection of the areas both under and facing the damages are considerably important. Based on the natural and sco-economic features in the damaged and relevant areas, some integrated reconstruction and protection strategies for mitigation of the disasters and sustainable development of the region as an optimal eco-sco-economic system are proposed. The strategies consist of appropriate flood control standards, optimal land uses, reasonable economic structures, and safe residences and environments, in which some detail measures of engineering and non-engineering are involved. The strategies may be suitable to the similar catchments in the Qin Mountains.
JSP23/W/08-A5 Poster 0830-03
VOLCANIC HAZARD ASSESSMENT FOR A PROPOSED HIGH-LEVEL RADIOACTIVE WASTE REPOSITORY AT YUCCA MOUNTAIN, NEVADA, USA
Charles CONNOR and Brittan Hill (CNWRA, Southwest Research Inst., 6220 Culebra Rd, San Antonio, Tx, 78238, USA, e-mail: cconnor@swri.org); Andrew Woods and Steve Sparks (Centre for Geophysical and Environmental Flows, University of Bristol, Bristol, UK,
e-mail: a.w.woods@bristol.ac.uk)
The proposed high-level radioactive waste repository at Yucca Mountain, Nevada, USA, is located within a geologically active basaltic volcanic field. Probabilistic volcanic hazard models for future eruptions through the proposed repository depend heavily on spatial controls on basaltic volcanism, including: Pliocene-Quaternary vent clustering, development of volcanic vent alignments, and localisation of vents along normal faults. When these spatial controls on past volcanism are considered, the probability of volcanic eruptions through the repository is estimated to be 10^(-7) to 10^(-8) annually, or 1:1000 during the 10,000 yr performance period for the repository. This estimate is greater than some previous estimates that do not consider structural controls on basaltic volcanism explicitly, primarily because of the location of the proposed repository within a broad density low produced by a half-graben. Modification of spatial hazard models to include this structure, which appears to have controlled past volcanism, provides a mechanism to link patterns in basaltic volcanic activity and crustal extension in a quantitative hazard assessment for the first time. This technique may be widely applicable to assessment of volcanic hazards resulting from small-volume basaltic volcanic fields.
JSP23/P/05-A5 Poster 0830-04
A SEISMIC HYDRAULIC BEARING
Federico BARTOLOZZI (Civil Engineering an Independent Researcher, via dei carracci 4, 21100 varese, Italy, email: ciuciuzza:iol.it)
The proposed bearing consists of two parts. The fixed part, connected to the building is a steel sliding surface in the shape of a spherical bowl with a safety side spandrel. The movable part, connected to the foundation-soil complex, consists of a movable steel ball (rolling friction) in direct contact with the overhanging spherical bowl; alternatively, the ball may be fixed and coated on the top with Teflon (sliding friction). The lower part of the ball is linked to a movable cylindrical piston housed in the central chamber of a hydraulic device, also having two lateral symmetrical chambers with movable pistons, subjected to the elastic reactions of pre-stressed springs. Two holes connect the lateral chambers with the central one. During an earthquake, the horizontal displacement of the foundation-soil complex slightly affects the rest state of the building and the corresponding seismic energy in the building is negligible. The vertical displacement of the foundation-soil complex does not notably alter the rest state of the building, where there is no danger of resonance occurring due to the damping action of the liquid contained in the hydraulic device. The main advantages of the seismic insulation system, characterised by this type of bearing, are: 1. self-catering of the building after an earthquake; 2. possibility of application to modern and old buildings with any planimetric shape; 3. negligible pendulous effet in the building; 4. economical competitiveness with the existing aseismic systems both with partial and total absorption of seismic energy; 5. negligible psycho-physical effects for the inhabitants.
JSP23/P/04-A5 Poster 0830-05
SELF-CENTERING ASEISMIC SYSTEM WITH ELASTIC BEARINGS AND HYDRAULIC DAMPERS
Federico BARTOLOZZI (Civil Engineer and Independent Researcher, via dei Carracci 4, Varese, Italy, email: ciuciuzza@iol.it)
The theoretical and experimental analyses emphasise the following characteristics of the proposed system: 1. the self-centring of the building after an earthquake; 2. the undulatory seismic energy in the building is constant and about 1% of the weight, by using bearing with sliding friction (pure Teflon). It is negligible, by using bearings with rolling friction (steel balls). In addition, it is independent on the seismic frequency and the soil displacement; 3. the vertical seismic energy in the building is minor and it increases both with the increase of the ratio between the frequencies (phase opposition) and with its decrease (phase); 4. the building remains almost motionless (negligible displacement) with respect to the horizontal translation of the foundation-soil complex for all values of the direction angle of the motion, of the soil displacement and acceleration; 5. in the interval of emergency vertical seismic frequencies, including the resonance frequency, the automatic starting of the dampers occurs. They progressively decrease the dynamic strain of the springs, which are integral parts of the bearings; 6. because of the sub-undulatory shock, the total load on the bearings increases for upward soil displacements and it decreases in the contrary case, both in phase and in phase opposition conditions; 7. the experimental tests, executed with reference to th undualtory shock, confirm the theoretical results.
JSP23/W/00-A5 Poster 0830-06
A PROPOSAL FOR COASTAL SAFEGUARDS
MARABINI
Abstract not available at the time of going to press
JSP23/W/37-A5 Poster 0830-07
ABOUT THE ENSO IMPACTS IN NORTH-EASTERN ARGENTINE
Norberto O. GARCIA and Maria del Valle Venencio (Facultad de Ingenieria y Cs. Hidricas - Univ. Nac. del Litoral, CC 495 - (3000), Santa Fe, Argentina. E-mail: nogarcia@ fich.unl.edu.ar)
Frequently the North-eastern Argentine Republic is affected by floods on the riversides of the Paraná river, originated in the precipitation on the High Basin, and/or floods caused by the local rainfalls. With the same recurrence characteristic, drought situations take place that also affects the region, going from an extreme to the other in a short time generating emergencies totally different, but equally serious.
The present work makes an analysis of the extreme situations of the Paraná River associating them with the development of the sea surface temperatures on the Pacific Equatorial Ocean (EL NIÑO, LA NIÑA and neutral years). In this sense was found, as it was hoped, that most of the EL NIÑO events were associated with extraordinary floods of the Paraná river; although there were some floods that they were associated with the neutral phase (1959). The phase LA NIÑA (cold events) not always was associated with notable low waters of the river.
The behaviour of the precipitations over the region was non-homogeneous, and not always coincident with what it was hoped from a statistical point of view (Ej. 1983). The situation of EL NIÑO 1997/98 was permanently scanned and climatologically predicted through several models. So much in the river such as in the region the forecasts were completed acceptably. While, the socio-economic impact of the extreme events was very graphically shown in the means of communication.
JSP23/E/53-A5 Poster 0830-08
ESTIMATION OF SEISMIC INTENSITY ATTENUATION LAWS FOR BANAT REGION
AURELIAN PANTEA and Iren-Adelina Moldovan Ivan (National Institute for Earth Physics, P.O. Box MG-2, Bucharest-Magurele, Romania, e-mail: pantea@infp.ifa.ro and iren@infp.ifa.ro)
An attenuation relationship for macroseismic intensities for Banat (Romania) crustal earthquakes has been developed. We have used a data base including macroseismic maps from 21 earthquakes occurred during the period 1900 to present with MGR>4.0. The general form of the attenuation relation used is: log (I)=f1(M)+f2(r,E)+f3(r,M,E)+f4(F)+e (where: I is the macroseismic intensity, M is the earthquake magnitude, r is the hypocentral distance, E is the tectonic environment, f4(F) is a function of fault type and "e" is a random variable representing the uncertainty in log(I). Comparison with other attenuation relationships have been made.
JSP23/E/48-A5 Poster 0830-09
TROPICAL CYCLONE RISK ASSESSMENT
M.V.RODKIN (Geophysical Center, Russ. Ac. Sci., 117296 Moscow, Molodezhnaya 3, rodkin@wdcb.rssi.ru); G.S.Golitsyn (Inst. of Physics of Atmosphere, Russ. Ac. Sci., Moscow); V.F.Pisarenko (Intern. Inst. of Earthquake Prediction Theory and Math. Geophysics, Russ. Ac. Sci., Moscow); M.I.Yaroshevich (NPO Taifun, Rosgidromet, Obninsk, Russia)
A method of statistical estimation of tropical cyclone hazard is suggested. Probabilities of exceeding of certain levels of wind velocity (quantiles of distribution function) at a given area for given time intervals T are evaluated. The evaluation is based on the following velocity/distance relation: V(R)=Vmax*(Rmax/R)**2, where Rmax is the radius of central part of tropical cyclone where maximum of wind velocity Vmax at given moment is observed. Accuracy of this relation is estimated by an error with standard deviation 7 knots. Suggested method is applied to typhoons in the Western Pacific, 1950-1988. The used catalog contains 1013 events. The 50%-quantiles (medians) and 90%- and 95%-quantiles of maximum possible wind velocity for time intervals T=1, 2, 5, 10 and 20 years at 4 areas were evaluated: Tokyo, Hong-Kong, Taiwan Isl., and Vladivostok. Problem of possible temporal change in the typhoons regime is discussed in connection with the solar activity and El-Nino regime. The suggested typhons risk assessment method can be useful for insurance industry and administration in areas subjected to tropical cyclones.
JSP23/E/11-A5 Poster 0830-10
LARGE SCALE DESTRUCTIONS OF BUILDINGS, THEIR CONNECTION WITH GROUNDS SPECTRAL PECULIARITIES DURING THE SPITAK EARTHQUAKE OF 12.07.1988 IN LENINAKAN (NOW GIUMRY), ARMENIA
Hrachya ABRAHAMYAN (Institute of Geophysics & Engineering Seismology, NAS RA, Leningradian 5, Gyumri, 377515 Armenia, email: iges@shirak.am)
Severely consequences of Spitak catastrophic earthquake force us to carry out the investigations revealing the causes of much more in quantity destructions. The most interesting aspect of testing the possibility of microvibrations using for prediction the grounds frequency characteristics is the comparision of buildings destructions measure by the grounds frequency elective property giving through the microvibrations. During the earthquake of December 7, 1988 with M=7.0 the full destruction of frame-panel 9-storey buildings (from 138 buildings in Leninakan were undamaged only 6) and frame-stone 5-storey buildings (from 335 buildings were undamaged 87) was observed.
Registrations of buildings natural oscillations before the earthquake and grounds dominant periods by microvibrations after the earthquake showed that statistically the largest amount of destructions were obtained on the parts of town where the grounds natural dominant periods T were approximately of 0.5-0.6 sec for five-storey frame-stone buildings. On the grounds with T=0.2-0.38 for nine-storey buildings and T=0.2-0.3 for five-storey buildings damages were been of least amounts. Natural periods of nine-storey buildings are of 0.5-0.6 and of five-storey buildings are of 0.25-0.4. The high damages may be explained by strong influence of oscillations due to resonance phenomenon when the ground natural dominant periods tally with the buildings natural periods.
In seismic microzonation of region the possible spectrum of disastrous earthquake must be assessed. By this assessment only the grounds frequency peculiarities may be compared with buildings frequency characteristics. Such a complex approach only enables us to solve correctly the task of connection of possible damages by grounds frequency characteristics. Neglect of this factor will bring to tragic consequences such that were been in Leninakan.
JSP23/E/32-A5 Poster 0830-11
MINERAL PATHOGENIC DEPOSITS INTO A HUMAN ORGANISM AS A SIGN OF NATURAL HAZARDS
Nadezhda PAL`CHIK (United Institute of Geology, Geophysics and Mineralogy of Siberian Branch of RAS, Koptjug prosp. 3, Novosibirsk 630090, Russia; email: nadezhda@uiggm.nsc.ru)
It is known that minerals exist not only into the Earth's crust but also into all human organisms. The physiogenic minerals contained into tooths and bones (as an apatite) are discovered also into pathogenic formations which can be found into different organs and tissues of a human body. We show, using the X-ray diffraction and the infra-red spectroscopy methods, that the apatite is present into urinary calculi, gallstones, dental stones, salivary calculi and also calcified cardiac valves as only phase of a mineral formation. Observations show that the full pathogenic mineralization of all living tissues of an organism occurs in some cases. Such peculiar natural hazard and its geographical distribution require a special attention and further investigation.
JSP23/W/60-A5 Poster 0830-12
NEGATIVE IMPACT ON HUMAN HEALTH FROM GEOPHYSICAL RISK FACTOR AT THE NORTH
VASSOVA
Abstract not available at the time of going to press
JSP23/W/61-A5 Poster 0830-13
GEOPHYSICAL RISK FOR HEALTH IN THE CIRCUMPOLAR AURORAL BELT
VINOGRADOV
Abstract not available at the time of going to press
JSP23/E/30-A5 Poster 0830-14
ASSESSMENT OF LANDSLIDE HAZARDS USING GEOPHYSICAL TOMOGRAPHIES
Simeon KOSTYANEV, Petar Srefanov and Peshka Stoeva (University of Mining & Geology, Sofia- 1100, Bulgaria, e-mail: skost@staff.mgu.bg)
Landslides and unstable slopes are among the major natural and man-made hazards affecting mankind and yet their causes, their consequences for human life and property, and possible strategies for mitigating their effect are not very well understood. We will note, that only in Bulgaria there are over thousand active landslides on populated and health resort areas. The material and social losses have not been calculated yet. But in preliminary data they are enormous. Numerous and dangerous are the landslides and unstable slopes in open-cast coal-mines too.
In this paper we offer methods for combined application of high-resolution electrical tomography and seismic ray tomography for characteristic of landslide hazards and unstable ones. The major aim here is to predict where and when landsliding will occur, establishing their variability in space and time, and appraising their impact on the natural and socio-economical environment.
The above methods are applied for the studying of concrete landslide in Bulgarian Black sea coast and on some unstable slopes in an open-cast coal-mine of Maritza-Iztok area. This combined application of electrical and seismic tomography for assessment of landslide hazard is very useful.
JSP23/E/45-A5 Poster 0830-15
SEISMICITY AND SEISMIC HAZARD STUDIES IN EGYPT AND SURROUNDING COUNTRIES
Samir RISAD (Geology Department, Assiut University, Egypt), Mahmoud Ghaleb (Geophysics Department, Cairo University, Egypt)
The tectonic setting of the Eastern Mediterranean Region is complicated because of the interacting effect of the principal plates: Africa, Eurasia and Arabia. The highest level of activity occurs at the northern margin of the Arabian plate, where it collides with Turkey and Iran. Strong earthquakes also occur along the western edge of the plate, along the Sea rift and the axis of the Red Sea Gulf of Aden. Egypt has a historical record of earthquake activity extending over the past 4,800 years. The most devastating earthquake in the recent history of Egypt, Dahshour earthquake, occurred some kilometers south of Cairo on the 12th of October 1992 damaged over 1,000 schools and other buildings, ed and injured over 7,000 people. In addition, other significant earthquakes occurred during this century interrupting the socio-economic development process of Egypt. Vulnerability to earthquakes increases steadily as urbanisation and development occupy more areas that are prone to the effects of significant earthquakes. The uncontrolled growth of cities in such areas are often associated with the construction of seismically unsafe buildings and infrastructures, mostly due to the insufficient knowledge of existing seismic hazard. Moderate and even small earthquakes may turn catastrophic in highly populated areas with poor building construction practice. In addition to the direct socio-economic impact of an earthquake, the long-term effects (the disruption of the economic chain, human resettlement, the reconstruction to modern standards) may last decades and absorb a considerable part of the national budget. In the absence of strong motion records a possible alternate method for seismic risk evaluation is the study of the attenuation of intensity with distance. For this purpose isoseismal maps for 17 historical and instrumental earthquakes that occurred in different parts of Egypt were analysed. Relations for intensity attenuation in different direction for different regions were obtained and have been used to calculate maximum intensity values all over Egypt. In addition, peak ground acceleration maps were produced for exposure time 10, 25, 50, 100 and 250 years, making use of an updated earthquake catalogue for Egypt. More than 20 seismogenic zones in and around Egypt were involved in the calculations. Hazard studies in Egypt have been carried within the framework of the regional IGCP Project 382, entitled "Seismotectonics and Seismic Hazard Assessment in the Mediterranean Basin (SESAME)", and in co-ordination with the activities of RELEMR Project. The results on Egypt were integrated with other available data for the surrounding countries.
JSP23/E/55-A5 Poster 0830-16
DIRECT AND INDIRECT LOSSES DUE TO EARTHQUAKES
KOFF G.L (1), Lobatskaya R.M. (2), Frolova N.I. (3). (1) Institute of Lithosphere, Russian Academy of Sciences, Moscow, Russia, (2) Irkutsk University, Irkutsk, Russia, (3) Seismological Center of IGE, Russian Academy of Sciences, Moscow, Russia
The stability of urban area development is strongly depended on the hazardous natural processes. In order to secure the stable development of the territory the expected losses due to future events should be estimated. Direct and indirect economic losses are distinguished. We understood direct economic losses due to natural processes as losses in economy within the current reproductive cycle which are expressed in terms of annual indexes of social economic development. All other losses are referred to indirect ones. They do not influence directly on the achieved results in the economy in the current year. The indirect losses is an estimation of negative consequences resulted from secondary effects. In contradiction to direct losses, indirect ones may arise and manifest within the long time interval. The indirect losses may not have a definite place in space and are usually characterised by cascade effects. Four main groups of factors, which influence upon direct and indirect economic losses due to earthquakes and other natural processes are distinguished; they are the following: origination, susceptibility, cycles and state. Different factors and their influence on losses due to earthquakes are analyzed. For different urban areas it is possible to construct in advance the index system which will allow to estimate the value of mentioned factors. Than it is possible to identify zones according to the weights of different factors which may be used in order to improve prevention, mitigation and response from future events. The system analysis of existing connections of urban areas with other regions will allow to estimate the rate of possible instability of the territory in the case of emergency and to obtain more reliable estimations of acceptable level of economic and ecological risks.
JSP23/C/U5/W/16-A5 Poster 0830-17
RECENT ANOMALOUS GEODYNAMICS OF PLATFORM FAULTS AS THE NEW ECOLOGICAL RISK FACTOR
CHURIKOV V.A., Kuzmin Yu.O. (both at United Institute of Physics of the Earth, Recent Geodynamic Lab., B. Gruzinskaya Str. 10, Moscow, Russia, email: vt.churik@relcom.ru)
New data on the existence of recent superintensive deformations (SD) of the ground surface are obtained for fault zones in aseismic regions (Russian platform, Pripyatskaya depression (Belorussia), Turanskaya platform (Turkmenistan) and etc.).
These deformations have amplitude approximately 20 - 50 ppm, extension 0.1-1.0 km, velocity of vertical and horizontal displacements up to 5 - 7 cm per year. They have a pulsating character (the duration of the impulses of the activity of 0.5 - 1.5 year). These anomalous deformations call into existence the ecological risk of two types. 1. Direct - by the plums of anomalous fluids during the periods of activating fault zones; 2. Indirect - by the casualties of ecologically dangerous objects (wells on oil field and gas deposits, pipelines, underground depots of gases and toxic wastes, atomic power stations and etc.). The mechanism of SD-processes is suggested based on the parametrical excitation ( the induction) of anomalous deformations in fault zones. In this case, the induction is evoked by small disturbances with nature and technogenic origins.
JSP23/L/08-A5 Poster 0830-18
DISASTER MITIGATION PROGRAMMES FOR EARTHQUAKES, CYCLONES, DROUGHTS AND LANDSLIDES
H.N. SRIVASTAVA (India Meteorological Department, New Delhi-110003, India,
email: snb.imd.ernet.in)
Peninsular India earthquake of September 1993 (Latur, Magnitude 6.3) which caused the death of about 10,000 persons and major damage to stone built mud houses led to the development of a World Bank aided project for relief and rehabilitation work besides reconstruction of cheaper but safe dwellings in the area. Under this project, broad band digital seismographs (GSN) were installed in India to improve earthquake risk assessment.
Issue of warnings about the land fall of tropical cyclones through INSAT based disaster warning system have helped in saving the lives of people living in coastal areas of peninsular India. Improvement of the rainfall measurements through another World Bank Project for the peninsular India will enable us to study agricultural droughts with greater reliability.
Recent landslides and floods in Garhwal and Kumaon regions during May, 1998 in Himalaya which have taken a heavy toll of life and property during August, 1998 have focussed the need for a coordinated approach for landslide zonation integrating seismological, meteorological, remote sensing and other observations.
JSP23/P/03-A5 Poster 0830-19
TOWER OF PISA: STABILITY RESTORATION PROPOSAL TO SAFEGUARD AGAINST SEISMIC RISK
Federico BARTOLOZZI (Civil Engineer and Independent Researcher, via dei Carracci 4, 21100 Varese, Italy, email: ciuciuzza@iol.it)
The proposed technique includes the solution of two problems. The former immediately provides to the removal of the instability due to the rotation in the north-south direction. The second problem consists in preserving the stability against the occurrence of two different phenomena: 1. the restarting of the instability, caused by a possible uneven subsidence of the foundation soil; 2. the instability consequent to an earthquake. Both phenomena could be avoided with the following complex operations: 1. planning and laying of a sub-foundation with geometrical and structural characteristics which ensure the stability of the foundation soil; 2. operation for preserving or decreasing the present inclination and, even, operation for conferring the perfect verticality, as well as, if wanted, the counter-inclination; 3. interruption of the solidarity between the building and the sub-foundation-soil complex, by using multidirectional movable bearings with low sliding or rolling friction, with or without dissipators of sub-undulatory seismic energy and laying laterally or rigid connections with alternative function of elastic linkages. This technique has two important advantages: 1. possibility to remove a future rotation of the Tower, due to an eventual subsidence of the soil; 2. easy maintenance of the sub-foundation structural elements, of the movable bearings and the side connections. The technique permits the removal only of the present instability, disregarding the seismic risk. In this case it is evidently less complicated and expensive. In addition, all operations for preserving or decreasing the present inclination and, even, for conferring the verticality and the counter-inclination are possible.
Saturday 24 July AM
SEISMIC RISK MAPS AND SCENARIOS: TOOLS FOR
PROTECTION AGAINST EARTHQUAKES
JSP23/C/U5/E/09-A6 Poster 0830-01
THE PREDICTABILITY OF EARTHQUAKE: TWO RECENT CASES IN YUNNAN, CHINA
Lin RONGHUI ( Seismological Bureau of Yunnan Province, Kunming 650041, CHINA); Tel: 86-871-3312339 Fax: 86-871-3315049 E-mail: ydj@public.km.yn.cn
China is one of few countries, which have the stipulation for issuing earthquake prediction and put it in practice. In the past three decades, the Chinese scientists did predict a few events of a certain type and with obvious characteristics. Though on a largely empirical basis such experience is a wealth, as the standpoint of practice should be first and fundamental in the theory of knowledge. The Menglian M7.3 earthquake occurred in the Sino-Burmese border (21¡ã59¡äN; 99¡ã04¡äE) at 05:46¡ä41.2¡åon July 12, 1995. Predictions of the intermediate-term(>1 year), short-term(3 months) and immediate-term (1 day before the mainshock) were made by analyzing in detail the observed seismic and precursory anomalies. The outcome of the prediction effort was only really significant when the immediate-term prediction was made at site just one day ahead of time. The Lijiang M7.0 earthquake occurred in 27¡ã18¡äN; 100¡ã13¡äE at 19:14¡ä18.1¡åon Feb. 3 1996. The observed precursory signals laid bases for making the intermediate- and short-term predictions. Yet, at the time of impending stage, a failure was made to locate the event, due to the superposition of post-precursors caused by Wuding earthquake (M=6.5) which occurred in central Yunnan in later October 1995.
JSP23/C/U5/E/07-A6 Poster 0830-02
CHARACTERISTIC PRECURSORS OF THE 1996 LIJIANG, YUNNAN, EARTHQUAKE (M=7.0)
Lin RONGHUI (Seismological Bureau of Yunnan Province, Kunming 650041, CHINA); Tel: 86-871-3312339 Fax: 86-871-3315049 E-mail: ydj@public.km.yn.cn
The Lijiang M7.0 earthquake occurred in Yunnan (27¡ã18¡äN;100¡ã13¡äE) at 19:14¡ä18.1¡åon Feb. 3, 1996. Before the event, precursory anomalies in the regional seismicity pattern were characterized as the absence of moderate-strong and small events around the source area. Since 1925, an average interval between M¡_6.0 events was 6.4 years in the Lijiang area, northwest Yunnan, with the longest lasting 15 years. The latest Yanyuang M6.7 and Ninglang M6.4 events in the area occurred in 1976, surpassing the longest interval. Along the northern segment of the Zhongdian-Dali seismic belt M¡_5.0 events were absent form 1983 to 1993, forming a gap of 150 km long. From 1990 to 1995, small events of M¡_3.5 were also absent in the source area (¡÷¡Ü60km). Activity of small events began to increase in the Yhongsheng earthquake window (¡÷=77km) in Dec.1995 and Jan.1996. Around the Eryuan area (¡÷=122km ), a foreshock swarm with the maximam magnitude 3.6 occurred on Dec.10, 1995. In addition, in the short and impending stage from Dec.1995 to Jan, 1996, 6 items of abnormal precursors were observed at 7 stations, namely the water level at Jianshui; water temperature at Liuku, Gangyuan, and Lincang; tilt at shiping; water quality (ion of HCO3-1) at Longling; and short leveling and short base line at Yongsheng. Besides, anomalous variations were also obtained from a synthetic analysis of precursory network data in the Lijiang area (which is consisted of 17 deep wells, 20 Radon points, 6 mercury points and 28 hot springs), and from the mobile gravity measurements in the networks of Western Yunnan Test Site before the event. Together with the seismic anomalies, all laid bases for making the intermediate (1-3 years)-, medium-short (1 year)- and short-term (months) predictions. Yet, at the time of impending stage, a failure was made to locate the event, due to the superposition of post-precursors caused by Wuding earthquake (M=6.5) which took place in later Oct. 1995.
JSP23/C/U5/E/10-A6 Poster 0830-03
RECENT CRUSTAL MOVEMENTS AND SEISMIC ACTIVITY STUDIES IN THE ASWAN REGION, EGYPT
Abdel Monem S. MOHAMED (National Research Institute of Astronomy and Geophysics, Helwan, Cairo, Egypt, email: mooonm98@yahoo.com)
Aswan region is one of the most important regions in Egypt and because it encompasses the vital engineering structure of the High Dam, it has been selected as a pilot project for the present study. Such a chose has been motivated by the fact that both geodetic and seismic data needed for the current investigation have been collected and become available from the Aswan region. So, the main objectives of the current research is to unify the results of the crustal movements and seismic studies which have been made in the Aswan region. This has been done for reaching the best understanding about the geodynamics of the area through investigating the relation between the crustal movements, seismic activity and earthquake occurrence and also for detecting the precursory events associated with earthquake occurrence. For the purpose of monitoring earthquake activity continuously around the Aswan Lake, a radio-telemetry network of 13 seismic stations was established. For monitoring the recent crustal movements several local geodetic networks were established around active faults in the area. Regional geodetic network covering the whole area of the northern part of Aswan Lake was established.
These studies use the seismicity recorded by the Aswan network from December 1981 to December 1997 and analyses different aspects of the data. Geodetic data were collected from local and regional geodetic networks. These studies were initiated to obtain an improved understanding of the seismotectonies in the Aswan region because this information is of importance in assessing the seismic risk.
JSP23/C/U5/E/19-A6 Poster 0830-04
SEISMICITY OF IRANIAN PLATEAU AND ITS BORDERING REGIONS
Arezou DOROSTIAN (Department of Geophysics, Azad University, North Tehran Branch);
M. R. Gheitanchi (Institute of Geophysics, Tehran University, email: mrghchee@chamran.ut.ac.ir)
During the 20th century, from Jan.1, 1900 to Dec.30, 1998,nearly 5100 earthquakes of magnitude 4 And above occurred in the region of 20-40 N and 40-75 E. The area lies Along the Alpine-Himalayan belt and surrounded by active seismic faults. This study shows a general aspect of seismicity of different parts of Iranian plateau and bordering regions. Historical and Instrumental data have been collected from several different sources. In order to minimize the uncertainty in magnitude estimation we present a uniform magnitude scale for the calculation of earthquakes. Seismicity maps for periods of time before 1965 and after that in five-year intervals were constructed. Seismic activity in some areas has changed with time. Within major seismic zones, large earthquakes fill gaps in the seismicity pattern. A grid interval of 0.5-degree in Lat. and Lon. covered the whole area. The seismic energy and strain release in each quadrangle were computed for each interval up to 29 years from 1970 to 1999. Maps of tectonic flux and two and three dimensional energy maps were constructed to define the distribution of seismic zones in the area and to give a dynamic measure of their variation. The a and b values for 99 years period are same for some seismotectonics provinces of area and the regions of homogeneous seismicity were constructed. The frequency distribution of earthquakes of different magnitude is discussed. Recurrence curves support a high level of activity for the Zagros zone and they indicate a lower rate of activity for northern Iran faults zone than for other areas in the region. Recurrence curves for central Iran area Indicate that the rate of activity in a given region may remain practically constant over periods at least as long as a century, whether or not large earthquakes occur in the region during those periods. Comparisons between seismic hazard, energy maps, faults location and earthquake epicenters distinguish areas which will be damaged or have a heavy casualty.
JSP23/L/01-A6 Poster 0830-05
EXPERIENCES GAINED IN THE RESPONSE TO THE EARTHQUAKE EARLY WARNING SIGNAL IN THE UNIVERSIDAD AUTONOMA METROPOLITANA, CAMPUS IZTAPALAPA IN MEXICO CITY
Delfino LASCARES. Universidad Autonoma Metropolitana, Iztapalapa Av. Michoacan y Purisima, Col. Vicentina, Delegacion Iztapalapa, C.P. 09340, A.P. 55-535, Mexico D.F. Tels. 724-46-98, FAX 724-46-88, email: held@xanum.uam.mx.
Since June 1997 a radio receiver of the Seismic Alert System of Mexico¸ City (SAS) was installed in the Universidad Autonoma Metropolitana, Campus Iztapalapa and an integral program for hazard mitigation has been applied in the campus. The population reached by the early warning signal is about 17,000 students and academic personnel, with an average near-by population of 45,000 people. To date 7 early warning signals have been received. During these early warning that occurred in working hours, evacuation has been carried out in an average time of 30 to 60 seconds. Surveys show that, since the SAS warning operation the attitude of the near by population toward earthquake prevention has changed. To date 90 percent of the population respond to the early warning signal. The Seismic Alert System (SAS) was developed by the Centro de Instrumentacion y Registro Sismico (CIRES). The alerts have provided as much as 30 to 60 seconds average in advance warning, before the ground motion sake reach Mexico City.
JSP23/C/U5/E/05-A6 Poster 0830-06
PRECURSORY SEISMIC SIGNALS DURING THE 1998 GUAGUA PICHINCHA CRISIS
HUGO A., Mario C. Ruiz, Minard L. Hall, Monica Segovia, Alexandra Alvarado, Acinoe Calahorrano, Darwin Villagomez, Diego Viracucha, Patricia Mothes, Andres G. Ruiz, Daniel Andrade; (Instituto Geofisico, Escuela Politecnica Nacional, P.O. Box 17-01-2759, Quito, Ecuador;
e-mail: geofisico@accessinter.net )
The Geophysical Institute in Quito, Ecuador, began the instrumental monitoring of Guagua Pichincha volcano in 1981. Until 1988, activity was characterized by a small number of earthquakes and sporadic phreatic explosions, which generated an explosion crater approximately 200 meters in diameter in the bottom of the caldera. In 1988, a swarm of VT earthquakes occurred 9 km southeast of the caldera at a depth of 8-12 km. Moderate phreatic explosions were detected in 1990, 1993, 1995, and 1997 during periods of rain. Between December 1997 and April 1998, three VT earthquake swarms were registered underneath the caldera, and in June 1998, an important swarm of VT earthquakes began 15 km northeast of the caldera. This swarm lasted until October, and at its height more than 100 earthquakes per day with a magnitude between 2.5 and 4.0 were noted. Furthermore, since June 1998, there have been hybrid earthquakes at depths less than 9 km.
A subduction earthquake with a magnitude of 7.1 occurred on the Ecuadorian coast 220 km from the volcano on 4 August. On 7 August, almost continual explosive activity began at Guagua Pichincha. This activity was characterized in the initial weeks by explosions followed by various days/hours of tremors. Between 7 October and 22 November, the tremors were shorter, with frequencies between 1.8 and 2.0 Hz. Between 22 November and 19 December, the number of explosions diminished with cycles of tremors between 28 and 32 hours. A new cycle of activity began on 19 December with spasmotic tremors and strong explosions followed by short episodes of tremors (<10 minutes) with frequencies of 1.6 Hz.
In addition, earthquakes characterized by narrow spectrum (between 2 and 5 Hz) have been registered since 10 September. These earthquakes have originated at shallow depths under the caldera and have accompanied periods of intense phreatic activity. Guagua Pichincha's continuing activity is attributed to various pulses of intrusion of small magmatic bodies, a process, which could ultimately result in a volcanic eruption.
JSP23/C/U5/E/12-A6 Poster 0830-07
THE HYDROPHYSICAL METHOD OF TSUNAMI ESTIMATION
Yury KOROLYOV and Alexander Poplavsky (Institute of Marine Geology and Geophysics, Sakhalin Scientific Centre, Nauki st., Yuzhno-Sakhalinsk 693002, RUSSIA,
email: tsunami@sakhmail.sakhalin.ru)
The estimation of tsunami danger is based on seismological data at present. It doesn't take into account inhomogeneity of tsunami source, directivity of tsunami, diffracting effects, which may both amplify and attenuate tsunami waves, and duration of tsunami. Therefore it gives some erroneous forecasts. Information of some level gauges placed on sea may confirm or refute tsunami danger. The hydrophysical method of tsunami estimation using information of some remote level gauges is based on well-known reciprocity principle. This method needs in minimal seismological data (time of beginning and co-ordinates of earthquake), data on sea level in three points and numerical "mareograms" in these points and in point to be warned. These "mareograms" must be obtained by tsunami simulation from some model tsunami sources placed on earthquake epicentre. This method takes into account inhomogeneity of tsunami source, directivity of wave radiation, different difracting and resonance effects. As a result the time of tsunami attack, form, heights and number of tsunami wave and duration of tsunami alarm are determined. This hydrophysical method will improve the reliability of tsunami warning and allow a creating of networks of local tsunami warning systems. This work was supported by grant 97-05-96625 from Russian Foundation for Basic Researches.
JSP23/E/56-A6 Poster 0830-08
HISTORICAL DOCUMENTATION OF THE SEISMICITY OF LESVOS ISLAND (E. AEGEAN, GREECE) IN THE SECOND HALF OF THE 19TH CENTURY: COMPARISON WITH THE INSTRUMENTAL PERIOD DATA
Vicki KOUSKOUNA (Department of Geophysics & Geothermy, University of Athens, 157 84 Athens, Greece, email: vkouskou@atlas.uoa.gr); Kostas Taxeidis (Psichari 20, Mytilini 81 100, Greece); Kostas Macropoulos (Department of Geophysics & Geothermy, University of Athens, 157 84 Athens, Greece, email: kmacrop@atlas.uoa.gr)
A total number of 32 earthquakes from Lesvos island for the period 1851-1899 are listed in the existing published catalogues, five of which were destructive and were felt in the Eastern Aegean and Minor Asia. A detailed investigation carried out on the island revealed new, local sources of information (manuscripts, newspapers, etc.) reporting the earthquakes of Lesvos. These sources, together with the existing ones, present a more complete seismic picture of the island, and almost double the total number of its earthquakes, i.e. 34 new single earthquakes (or series of earthquakes) were located, one of which (in 1882) was damaging. The seismicity of the island in the 20th century, as derived from instrumental data, for a time window of 50 years, was compared to the above mentioned period, in an effort to: a) re-evaluate the parameters of the known, major destructive earthquakes by adding the new sources of information, and b) answer to certain questions of tectonic character, i.e. the existence of foreshock/aftershock activity and its characteristics. In this sense, the catalogue of earthquakes of the area is extended backwards up to 1850, and the completeness of its seismicity is tested. This enables the creation of an artificially complete data set, which will therefore contribute to more realistic local seismic hazard assessment and microzonation studies.
JSP23/E/38-A6 Poster 0830-09
MODULE AND GRADIENT HIGH-SENSITIVITY MEASUREMENTS OF GEOMAGNETIC FIELD VARIATIONS AT THE SEISMIC RESEARCHES
Oleg KUSONSKI (Observatory Arti, Institute of Geophysics, Urals Branch of Russian Academy of Sciences, Geophysics Str., 2a, Arti, Sverdlovsk region, 623350, Russia); Vladimir Sapunov and Olga Dekusar (Ural State Technical University, Quantum Magnetometry Lab, Mira St., 19, Ekarerinburg, 620002, Russia)
The researches are carried out at the observatory Arti (WDC's mnemonic is ARS, coordinates are 56˚25.8¢ N, 58˚33.7¢ E) that is located on the Preduralsky pericratonice trough of the East-European platform. This area is seismically active. Observable here earthquakes have both natural and industrial origin. The last is connected with production of minerals and oil. The magnetic field of this region is characterized by presence of anomaly up to 1200 nT. The module and gradient variations are measured by the proton Overhauser's magnetometer POS-1 with resolution 0.001 nT (sensitivity up to 0.02 nT and 0.01 nT/meter at single measurement). At the same time a registration of super-long-period seismic oscillation (SSO) are made by the ARU IRIS station. A gradiometer allows to control the real measurement sensitivity for absolute value of magnetic fields and to locate geological and technogeneous effects caused by a near zone. The submitted methods and equipment allow to study geoblocks movements creating intensive deformations of mountain breeds, geoblocks response to tectonic factors, SSO excitation mechanism, trigger factors of earthquakes. The data can essentially soften dramatic and economic consequences of earthquakes at the mining enterprises of Ural.
JSP23/E/45-A6 Poster 0830-10
OBSERVED AND PREDICTED INDUCED SEISMIC IMPACTS IN PREADRIATIC COASTAL AREA OF ALBANIA
Siasi KOCIU (Seismological Institute, Tirana, ALBANIA, email: kociu(sizmo.tirana.al)
Albania, situated on Western Balkans, with a coastal line of 470 km long, represents an attractive area for the future development of tourism. Adriatic seacoast of Albania with many , as one of the most populated areas of the country (where more than 70% of the population is concentrated, with many inhabited centers as those of Durres and Vlora towns in seacoast and Shkodra, Fieri and Tirana (capital), not far away (20-40 km), from the seacoast), represents one of the most hazardous seismic zones of the country, where many seismic impacts were observed during the past earthquakes and may be developed during expected future earthquakes.
Preadriatic area as a flat area filled mainly by recent very poor Quaternary sediments of thickness down to 100-150 m, with shallow underground water level, represents an area where a lot of soil in stabilities were observed during past earthquakes and can be observed in the future. Based on seismic hazard assessment procedures at local level for two of the biggest coastal cities of Albania ( Durres and Vlora) it is shown that during the expected strong earthquakes induced seismic impacts as liquefaction of sands , new and induced landslides and appearance of fault rupturing on free surface can be observed not only along Adriatic seacoast, but especially within urban areas of these two cities.
JSP23/E/07-A6 Poster 0830-11
THE RISK OF LARGE VOLCANIC ERUPTIONS AND THE IMPACT OF THIS RISK ON FUTURE OZONE DEPLETION
Howard ROSCOE (British Antarctic Survey/NERC, Madingley Rd, Cambridge CB3 0ET, UK,
email: h.roscoe@bas.ac.uk)
Ozone depletion at mid-latitudes due to reactive halogens from man-made halocarbons is enhanced by the increase in stratospheric sulphate aerosol, which follows large volcanic eruptions. Mid-latitude ozone depletion due to halocarbons almost doubled for the two to three years following the eruption of Mt Pinatubo in 1991. Although the Montreal Protocol is expected to reduce amounts ofhalocarbons in the atmosphere during the next century, the predicted reductions are such that stratospheric ozone will be at risk from such depletion enhancement for the next 50 years. Vulcanological mechanisms, models, and measurements in ice cores, suggest that large volcanic eruptions are random and that their global rate is constant over periods of a few centuries. From the rate of large eruptions observed in ice-cores, the probability of one or more eruption, the size of Pinatubo or larger, is 58% in 50 years. This probability is large enough that it should be taken into account in predictions of future ozone loss. Several of the eruptions in the ice-core record were many times larger than Pinatubo, so that a more comprehensive analysis, which also included the probability of eruptions as a function of size, would be beneficial.
JSP23/E/47-A6 Poster 0830-12
STATISTICS OF EARTHQUAKE HAZARDS
M.V.RODKIN (Geophysical Center, Russ. Ac. Sci., 117296 Moscow, Molodezhnaya 3,
email: rodkin@wdcb.rssi.ru); V.F.Pisarenko (Intern. Inst. of Earthquake Prediction Theory and Math. Geophysics, Russ. Ac. Sci., Moscow)
Earthquake tolls and economic losses in 1900-1996 years are examined in connection with earthquakes regime and economic conditions in different regions. It was shown that while the number of events with small and moderate number of victims and losses increase with time in a non-linear manner the large losses that constitute the major part of the total number of victims and losses have a linear increase with time. The non-linear increase with time of the total number of victims and losses is caused mainly by the Pareto-law distribution of losses from earthquakes, thus a high non-stationarity of regime of hazards assumed by a few authors is apparent. The limitations inherent to the Pareto-law distribution of losses are discussed and the value of maximum possible seismic hazard is evaluated. The connection of regime of seismic disasters with regional economic situation is discussed also. It was shown that while the losses from earthquakes have a tendency to increase with time, the number of victims and losses we normalised with the national income per capital have a tendency to decrease. A prognosis of number of victims and losses from earthquakes till 2020 year is presented.
JSP23/E/51-A6 Poster 0830-13
INTERNATIONAL GPS TEST-AREA FOR DEFORMATION FORERUNNERS OF EARTHQUAKE STUDY
Mikhail PRILEPIN (United Institute of Physics of the Earth, B.Gruzinskaya Str., 10, 123810 Moscow, Russia, email: prilepin@uipe-ras.scgis.ru)
One of the reasons why the problem of earthquake prediction is far away from the solution stipulated is the lack of real international co-operation on experimental study and evaluation of significance of different forerunners. Many scientists today share the opinion that deformation forerunners are primary and their study can help in understanding the processes of preparation of earthquakes and prediction of event. The favorable factor nowadays is the availability of very effective GPS technology for the study of deformation forerunners on large territory with high accuracy and with the possibility for automatization of gathering and processing of the data. The next step in instrumentation is combining GPS with SAR interferometry, which is making the first but a very successful step toward the study of geokinematics. In the report discussed, the items dealing with the determination of the epicenter position, magnitude and time of shock using the data accumulated on GPS networks of different levels developed in seismically active areas. The consideration about the selection of place for a test-area, its status, sequence of development of the GPS networks, transition of data, gathering of auxiliary data and activity of the center for processing and analyzing the data are discussed. The consideration about the possibility of united study of different kinds of forerunners: seismic, geoelectromagnetic, variation of ground water level and emanation of noble gases are also presented shortly.
JSP23/C/U5/P/01-A6 Poster 0830-14
THE THREE STRONG EARTHQUAKES, NORTH CHINA, CHINA AND ITS STRUCTURAL SIGNIFICANCE
Lu PEILING (Centre for Analysis and Prediction, CSB, Beijing (l00036), China, Tel: 010-88015557, Fax: 010-68218604)
Abstract The seismic activities before and after strong earthquakes, the source mechanism of mainshocks, and the geological structure of the epicenter area of three strong earthquakes (the 1976(M7.8) Tangshan, the l989(M6.1)Datong-Yanggao and the 1998 (M6.2)Zhangbei-Shangyi earthquake) have been investigated. The structural significance of the three strong events is also discussed. The results show that 1. In according to the seismic activities before and after mainshocks, three strong events occurred in the north margin of North China faulting block area. The occurrence of three events was resulted from the most recent abrupt slip on a NE-trending Changdong fault zone, a NE-trending Shanxi grabon zone and a NWW-trending Zhangjlakou-Bohai fault zone, respectively. 2. In according to the mainsbock location, the events was in the intersecting area of the faults, therefor its sequences have the rich aftershock action, the most of strong aftershocks and the energy attenuation slow. 3. The source mechanism solutions of mainshocks are in agreement with the regional stress field with the P axis in the NEE-SWW direction of North China, but there are a difference in the fault motion type, 1976 event shows the northeastern striking high-angle strike-slip faulting mechanism, 1989 event has the strike-slip with the normal faulting motion, and 1998 quake is the thrust fault type. Those might correspond upon the structure of the epicenter area. 4. The epicenters is in or near Cenozoic-aged faulting basins with the Cenozoic -aged baselts, the genesis of the strong earthquakes which are derived from baselts may is the rising model of the hot material. Due to an action of the local hot stress the earthquakes occurred. 5. the mainshock faults are not at a great active structure, even there is not active fracture in the surface of the epicenter area.
JSP23/C/U5/P/04-A6 Poster 0830-15
SEISMIC HAZARD ASSOCIATED WITH SUBMARINE NEOTECTONIC FAULTS IN GREECE
Joanna PAPOULIA (National Center for Marine Research, Agios Kosmas, Hellinikon, 16604 Athens, GR)
Seismic hazard analyses are associated with large uncertainties when historical data are insufficient to define seismicity rates. These uncertainties may be decreased however in areas where seismicity is shallow, and produced by Quaternary faulting, by incorporating geological data in the analysis of seismic hazard. A tool towards the integration of the so-called prior information of seismicity, obtained from geological data, with historical observations is the Bayesian probability theory. This theory is tested here to estimate the seismic hazard associated with submarine active fault zones in the area of Greece. Prior estimates of seismicity are developed from slip rate measurements obtained from offsets of geological formations. The analysis demonstrates the importance of uncertainty in the Bayesian estimate of seismicity, and subsequently in the estimate of seismic hazard.
JSP23/C/U4/E/03-A6 Poster 0830-16
GUAGUA PICHINCHA: MANAGING THE CRISIS
HUGO A. YEPES; Instituto Geofisico, Escuela Politecnica Nacional, P.O. Box 17-01-2759, Quito, Ecuador; e-mail: geofisico@accessinter.net
Guagua Pichincha is a dacitic volcano located 12 km west of Quito (pop. 1.2 M.), the capital of Ecuador. It has erupted five times in the last 1,030 years (970, 1560, 1575, 1582, and 1660), with a recurrence period of approximately 500 years during Holocene. In July/August 1998, there was a commencement of seismic and explosive activity at levels superceding those seen since the installation of the monitoring network in 1988. The increased activity, which peaked during late September, precipitated the declaration of a yellow alert by the city of Quito on 1 October.
The Geophysical Institute, drawing on its experience and expertise, acted as a catalyst for the city's actions given the city's lack of preparedness and inability to initially grasp the gravity of the situation. The initial step for the government in dealing with the crisis was the designation of the mayor of Quito as the overall response coordinator. The city established an operations/information center; determined populated areas at risk; identified public sectors likely to be affected; and cleared debris from flow areas and potential evacuation routes. Contingency planning included one evacuation drill; periodic meetings of governmental entities; solicitation of heavy equipment and medical supplies from foreign governments and NGOs; the development of ways to minimize impact to the water supply, power grid, and telecommunications; and the planning for ash removal, police deployment, evacuation of aircraft, ingress/egress of the city, and procurement of food and fuel. Educational efforts comprised press conferences, briefings, and press bulletins.
Any crisis has its difficulties. Some problems are unavoidable, some can be mitigated by adequate funding, and others are preventable. Problems encountered by the city have included the inability to control rumors, inability of the government to ameliorate the public's linkage of the alert declaration to local political events, poor management of the initial alert declaration, confusion over alert level definitions, difficulty in maintaining public interest over the long term, the release of overly technical information to the public, delays in developing contingency/evacuation plans, reluctance to disclose all available information on potentially affected areas, the ill-defined role of the operations center, inadequacies in the call-down list, a failure to publicize an alarm system, and insufficient funding. Yet despite these problems, the city has made great progress in recognizing the hazard and addressing the risk.
JSP23/C/U4/W/01-A6 Poster 0830-17
VOLCANIC HAZARD ASSESSMENT AT THE DENSELY INHABITED ISLAND OF ISCHIA
Sandro de VITA, Giovanni Orsi (Osservatorio Vesuviano, 80056 Ercolano -NA- Italy,
email: devita@osve.unina.it) Fabio Sansivero (Dip. Geofisica e Vulcanologia. Un. "Federico II", 80138 Napoli, Italy)
Ischia is a volcanic island located in the north-western corner of the Gulf of Naples. Volcanism begun more than 150 ka B.P. and the last eruption took place in 1302 A.D. The largest caldera forming eruption generated the Mt. Epomeo Green Tuff and occurred 55 ka B.P. Resurgence of the central part of the caldera begun around 28 ka B.P. and caused a net uplift of about 900 m of the Mt. Epomeo block. It occurred through a simple-shear mechanism that determined the conditions for magma to rise to surface only along normal faults within the eastern sector of the resurgent block. Almost all the volcanic vents of the last period of activity (10 ka B.P.-1302 A.D.) are located in the eastern part of the island. During this period 46 eruptions, effusive and explosive, occurred mainly between 2.9 ka B.P. and 1302 A.D. Effusive eruptions produced lava flows and domes; explosive eruptions formed tuff-rings, tuff-cones, and variably dispersed pyroclastic deposits. Eruptions were separated by periods of quiescence that lasted up to few centuries. Slope instability, likely triggered by resurgence dynamics, generated landslides and mud-flows shortly before and after eruptions. The magmatic system is still active, as testified by the intense historical, volcanic and seismic activity, and by widespread thermal springs and fumaroles. The island is inhabited by about 50,000 peoples that greatly increases during summer. Farming, wine industries and a complex network of commercial exchanges with the near city of Naples, contribute to determine a high volcanic risk in this area.
JSP23/W/72/C/U4/W/03-A6 Poster 0830-18
EVIDENCE FOR VOLCANIC INFLUENCES ON MEXICO CITY AEROSOLS
G. B. RAGA (Centro de Ciencias de la Atmósfera, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04510, México DF, México, email: raga@servidor.unam.mx), G. L. Kok (National Center for Atmospheric Research, Boulder, CO 80303, USA, email: kok@ucar.ncar.edu), D. Baumgardner, A. Báez and I. Rosas(all three at: Centro de Ciencias de la Atmósfera, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04510, México DF, México, email: darrel@servidor.unam.mx)
In situ measurements of sulfur dioxide (SO2), carbon monoxide (CO) and sulfate mass provide evidence that aerosol composition in Mexico City is affected by emissions from the neighboring volcano, Popocatepetl. The data suggest that there are two distinct pathways by which SO2 is incorporated into particulates. Periods of high humidity, fog, and rain are accompanied by elevated sulfate mixing ratios, attributed to aqueous chemistry. Similarly, elevated sulfate concentrations in low humidity periods appear to be a result of adsorption onto existing particles. These two mechanisms are important for understanding the processes associated with particle formation in this highly polluted urban area. Under the influence of volcanic emissions, SO2 concentration is more than four times the average value and particulate sulfate is a factor of 2 larger.
JSP23/C/U4/W/05-A6 Poster 0830-19
SAN SALVADOR, EL SALVADOR, A HIGH RISK, MULTIPLE HAZARD MEGACITY
D J SOFIELD, J W Vallance, and W I Rose (Geological Engineering and Sciences, Michigan Technological University, Houghton, MI, 49931, email:djsofiel@mtu.edu)
Volcanism and earthquakes are the most dire geological hazards that threaten San Salvador, El Salvador’s largest city (population, 1.7 million), with a rapidly growing population, and few plans or resources for hazard mitigation. Financial, transportation, and governmental centers of El Salvador all reside within San Salvador. The city lies on a plain within severe hazard zones of two active volcanoes (San Salvador to the W and Ilopango to the E) and also lies in a zone of major subduction earthquakes.
In the past 60 Ka, a caldera 12 km E of the city now occupied by Lake Ilopango erupted at least four significant pyroclastic deposits, each of which blanketed the valley that San Salvador now occupies. The last of these eruptions devastated all El Salvador in AD 260 and drove pre-Classic Mayan civilization northward into the jungles. A dome eruption in 1880 and small seismic swarms beneath the lake indicate continuing unrest. Neither San Salvador volcano nor its numerous flank vents has erupted catastrophically since European colonization, however numerous explosive eruptions occurred prior to that. San Salvador volcano erupted ash-rich tephra and pyroclastic flows 800 years ago and caused mudslides that would likely kill many thousands today. Because of the frequency of earthquakes, the people of San Salvador are much more aware of seismic risk than volcanic risk. The city has had to rebuild 7 times after earthquakes since 1712. The most recent devastating earthquake in 1986, killed
1500, injured 10,000 and left 100,000 homeless. Thick unconsolidated pyroclastic and tephra deposits amplify the effects of shallow-focus, moderate magnitude earthquakes beneath the city. Timely international involvement could provide the impetus that San Salvador needs to begin effective hazard-assessment, monitoring, and educational programs. A significant part of this work will be to make the population of a volcanic country more aware of its vulnerability to volcanic hazards. The recent occurrence of hurricane Mitch offers an opportunity to advance all hazard work in Central America.
Monday 26 July AM
NEW PHENOMENA, APPROACHES AND TECHNIQUES
JSP23/W/28-B1 Poster 0830-01
METHODS OF EXTREME SEA LEVEL AND CURRENTS VALUES CALCULATION
Oleg ZILBERSTEIN, Guennady Safronov, Sergei Popov, Mikhail Chumakov (all at State Oceanographic Institute, Kropotkinski per. 6, 119838, Moscow, Russia, email: oleg@soins.msk.ru)
Hydrometeorological support for marine branches of the economy and safety of human activities on offshore regions requires knowledge of the main marine parameters (in particularly sea level and current extreme values). As a rule long-term observations in offshore regions are absent. The most dangerous rise and fall of sea level and also extreme currents are result from the combined effect of tides and storm surges. A special automated technology including hydrodynamic and probabilistic modelling was developed. On the basis of historical information and observation series analysis for region of interest, extreme storm cases with corresponding weather maps are selected. Following computation of earth-surface level wind and atmospheric pressure gradients are produced. On the base of this information the hydrodynamic calculation of storms and summary (accounting tides) sea level oscillations and currents are calculated with help of verified 2D and 3D hydrodynamic models. Baroclinic models are actively used last years. With the help of produced probability models, which are based on Gumbel low and Langbein relationship, the results of numerical modelling are processed and long-return period characteristics of sea level and currents at different horizons are determined. Produced complex of models and methods is successfully used within researches and survey for number of designing objects in Barents, Kara, Baltic, Caspian, and Sea of Okhotsk. This approach allows us to produce computer maps of long return period characteristics of sea levels and current
JSP23/W/33-B1 Poster 0830-02
SEARCH FOR THE EARTHQUAKE PRECURSORY SIGNATURES BASED ON FRACTAL ANALYSIS OF THE ULF GEOMAGNETIC DATA
Natalia SMIRNOVA (Institute of Physics, St. Petersburg University, St. Petersburg, 198904, Russia,
e-mail: nsmir@snoopy.phys.spbu.ru); Masashi Hayakawa and Tetsuya Ito (The University of Electro-Communications, Chofu, Tokyo 182-8585, Japan, e-mail: hayakawa@whistler.ee.uec.ac.jp)
An attempt to use fractal methods of time series analysis for searching the earthquake precursory signatures is fulfilled on the basis of ULF geomagnetic data obtained during Guam earthquake (EQ1) on August, 8 1993 (M=8) and Biak earthquake (EQ2) on February, 17 1996 (M=8). The observing places were situated both near the epicenters (Guam, 65 km off EQ1 and Biak, 100 km off EQ2) and far away (Darwin, 1200 km off Biak EQ). The chosen period covered a few months before and after the earthquakes in order to reveal the large-scale dynamics of scaling (fractal) characteristics of the pulsations. It is revealed that in the seismoactive region the ULF spectrum of emissions exhibits a power law behavior which is typical for self-organized critical dynamics. For Guam EQ the slopes of spectra and the fractal dimensions of ULF time series manifested stochastic fluctuations between values 2.5-0.7 with pronounced tendency for slope to decrease and for fractal dimension to increase in the process of the earthquake preparation.Taking into account the certain value of the critical slope we suggest that the gradual increase of the intervals with slopes less than this critical one prior to the earthquake may be considered as an earthquake precursory signature. The peculiarities revealed on the basis of ULF data of Guam EQ is verified on the materials of Biak EQ. The fractal properties of ULF emissions in seismoactive and seismoquiet regions are compared. The research was supported by Grant 98-05-65554 from Russian Foundation for Basic Research.
JSP23/C/U5/E/13-B1 Poster 0830-03
RESEARCH ON CORRELATION OF ASTRONOMIC FACTORS AND EARTHQUAKES
Hu HUI; Li Yongsheng (Yunnan Observatory, Academia Sinica, Kunming, 650011 China)
The effect of astronomical factors on the major earthquakes in China and the world is discussed in detail in this paper. The results show that the major earthquakes, especially the ones of above magnitude 7.0 are evidently affected by the astronomical factors, such as the Earth rotation, solar activities and lunar orbital motion. Only different seismotectonic belts or zones have different responses to an astronomical factor. The node of the lunar orbit with the earth's orbit regresses towards the west on the ecliptic, with a period of 18.6 years. The precession of the lunar ascending node causes the inclination between the moon's path and the equator to change continuously from 18.28 to 28.58 degrees. The seismic activities of the main seismic belts in the world are obviously affected by the period of 18.6 years and only their active periods appear alternately, which shows that different locations of the moon correspond to different seismic belts or regions on the Earth. This bears analogy to the fact that the change Earth's climate with a period of a year is caused by the different quantities of arrival of solar radiation due to the inclination of the ecliptic to the equator.
In China, 8 seismic events over M 8.0 occurred since 1820 happened to be during the acceleration of the Earth rotation(DAER). Among the 106 events over M 7.0 occurred in the 20th century, 72% were during the DAER and 71% happened when the inclination changed from the maximum to minimum. Most of the events happened in the descending phases of solar activities.
JSP23/E/16-B1 Poster 0830-04
POINT-LIKE PROCESSES AND CATASTROPHE PREVISION
Giovanni P. GREGORI (IFA-CNR, via Fosso del Cavaliere 100, 00133 Roma, Italy;
e-mail: gregori@atmos.ifa.rm.cnr.it)
A frequent approach when attempting at managing a natural catastrophe is in terms of a numerical model, by which we try at forecasting its occurrence in space and time. Sometimes this results to be difficult or even unrealistic. On a more pragmatic ground we can rather appeal to a formal analysis of the historical time series of every catastrophe of concern. Only approximately, however, such series can be likened to a point-like process, because the "detector-mankind" experienced substantial changes vs. time. Nevertheless, such algorithms can be approximately applied by means of a few suitable assumptions. Four basic viewpoints can be considered: (i) either by assuming that phenomena are periodic; (ii) or by assuming that an event occurs only whenever so m e energy threshold is attained (calorimetric criterion); (iii) or by assuming that it occurs only whenever the system experiences some abrupt change of its boundary conditions; or (iv), whenever no such algorithm is viable due to scanty observational inf o rmation, just by applying the box counting method, or some other more or less related and/or equivalent fractal algorithm. The mutual relations, advantages, and drawbacks of either one such approach are briefly discussed, with a few applications. They al r eady lead to an apparently successful long-range forecast of a large flood in northern Italy occurred in 1994, and to the prevision of the next explosive eruption of Vesuvius. But, the success of every such application is closely determined by the quality of the historical database, or by the physical information that is fed into the analysis, rather than by mathematics that per se have only to be concerned with avoiding that some arbitrary non-physical input is added, based only on the human need for simplicity.
JSP23/W/88-B1 Poster 0830-05
SIMULATION OF ANOMALOUS BEHAVIOUR DURING THE NORTHBRIDGE 1994 EARTHQUAKE
GALIEV
Abstract not available at the time of going to press
JSP23/E/22-B1 Poster 0830-06
PHASE OF MOON, INCLINATION OF MOON'S PATH WITH EQUATOR AND STRONG EARTHQUAKES IN YUNNAN
Li XIAOMING (Yunnan Observatory, Chinese Academy of Sciences, P.O.Box 110, Kunming; Yunnan Province, 650011, P.R.China)
Yunnan Province lies in the southwestern part of china, adjoining the juncture of the Eurasian plate and Indian plate, with the complicated geological structure, frequent seismic activities and the Mediterranean seismic belt passing through the province itself. It is found from the analyses that the rate of recurrence of earthquakes has close correlation to the position of the Moon at the last quarter and especially near the new Moon and the last quarter of the Moon earthquakes occur frequently. In the 19th and 20th centuries the rates of recurrence of the earthquakes with M 6.2 near the two phases of the Moon are respectively 6.2 times and 4.5 times as frequent as the average rate of recurrence, having a stripe-shaped distribution and the major earthquakes with M 7.0 almost occurred in the maximum and minimum year of the inclination and within two years after or before it in particular. As for the solar and lunar tidal forces, most of the earthquakes occurred in the time interval when the horizontal component of the tidal force made the greatest change. This shows that an earthquake can be excited by the position of the Moon and the tidal forces of the Sun and the Moon.
JSP23/E/46-B1 Poster 0830-07
IMPACT OF THE HYDROLOGIC EXTREMES OVER THE WATER TABLE IN THE "PAMPA HUMEDA" (ARGENTINA) AND ITS RELATIONS WITH THE ENSO.
Maria del Valle VENENCIO and Norberto O. Garcia (Facultad de Ingenieria y Cs. Hidricas - Univ. Nac. del Litoral, CC 495 - (3000) Santa Fe, Argentina. - E-mail: mvv@fich.unl.edu.ar)
This paper aims to create the bases in order to carry out, starting from seasonal and interannual climate prediction, a seasonal and interannual prediction of availability of groundwater resources coming from the unconfine acuifer in the productive areas of the "Pampa H=FAmeda" in the Argentine Republic.
The regional averages of the depth of the unconfined aquifer get rid suppose affected only for climatic variations. Also, the use of the groundwater resource is considered constant. Keeping in mind that the several water resources states in the region obeys several relationships between the variables precipitation, evaporation and evapotranspiration, it was carried out a serial water balance and correlations between the variability of the precipitation and the depth of the unconfined aquifer.
So, we can say that the precipitation produces decreasing or rising water level. As it was demonstrated the relationship between the ENSO and the precipitation on the Southeastern South America (SSA) by several authors, presently work was aimed to establish relationships between the water table and the ENSO. This correlation also provides useful information about the predictability of the future piezometric levels for sustainability of groundwater resources.
Then, the main conclusion of this work is that the water table level is predictable in function of a predictor like El Nino.
JSP23/E/04-B1 Poster 0830-08
LONG REPOSE PERIODS IN THE ERUPTIVE HISTORIES OF RECENT KAMCHATKA VOLCANOES: WHAT VOLCANO CAN BE RECOGNIZED AS EXTINCT?
Vera PONOMAREVA, Olga Braitseva, Ivan Melekestsev (Institute of Volcanic Geology and Geochemistry, Piip Ave., 9, Petropavlovsk-Kamchatsky, 683006, Russia,
email: ponomareva@geology.ru) Leopold Sulerzhitsky (Geologic Institute, Pyzhevsky per., 7, Moscow, 109017, Russia, email: suler@ginran.msk.su)
Detailed studies of the eruptive histories of Kamchatka volcanoes, based on geologic mapping, tephrochronology and radiocarbon dating, allowed us to document main repose periods in the lives of most Holocene volcanoes and monogenetic volcanic fields, and to determine their duration. It appeared that dormant periods as long as 500-1000 years were common in the lives of the volcanoes of various morphology, types of activity, and composition of eruptives. The best known example is Bezymianny volcano which was silent for about 1000 years before the 1955-56 large eruption. Longer repose periods up to 2000-3000 years were not rare. The longest repose periods - about 3500 years - were recorded at Kikhpinych and Dikii Greben' volcanoes; after a long dormancy both volcanoes were able to resume their activity. These data suggest that at least in Kamchatka a volcano should be considered potentially active (and thus, potentially hazardous) if it was proved to produce at least one eruption within the last 3-4 thousand years. This approach has allowed us to add some more names to the list of active volcanoes: Taunshits, Khodutka, Dikii Greben', Khangar volcanoes, which have been considered extinct and were not included in any catalogues of active volcanoes, appeared to have large eruptions within the last 3000 years, as well as Tolmachev Plateau and some other volcanic fields.
JSP23/E/57-B1 Poster 0830-09
THE CELLULAR AUTOMATA MODEL SCIARA FOR LAVA FLOW SIMULATION: APPLICATIONS AND RESULTS
G.M. CRISCI, A. Di Francia, S. Di Gregorio, F. Nicoletta*, R. Rongo, W. Spataro (Dip. di Scienze della Terra Dip. di Matematica *Dip. di Chimica ersità della Calabria, I 87036 Arcavacata, Italy)
Cellular Automata (CA) represent a parallel computational method in alternative to differential equations, for modelling very complex phenomena, whose evolution can be considered based exclusively on local interactions. The CA model SCIARA for the simulation of lava flow was developed and subsequently improved several times by our research group. A lava flow is described in SCIARA as a system with discrete time and space; the space is represented by regular cells (square or hexagonal) two-dimensional cells, whose specifications (substates) describe the main physical characteristics of the corresponding portion of space: altitude and, for each lava layer, lava thickness, temperature, lava outflows toward the adjacent cells; furthermore a division in lava layers can be considered in a refinement of the model. The CA evolves changing the state of all cells simultaneously at discrete times. Input for each cell is given by the states in the adjacent cells; the evolution of the phenomenon is mainly given by the computation of the outflow from the cells and the change of the remaining substates. SCIARA was applied in different times to 1986/7 and 1991/2 Mount Etna eruptions. The results were satisfying within limits to forecast the lava flow path, according to the surface covered by lava. The main parameters of the model for Etnean lavas were found; then simulations were performed in order to evaluate the risk in some inhabited Etnean area (the towns of Nicolosi, Pedara and S.Alfio) considering future catastrophic events. We consider the evolution of SCIARA, the main results and a critical discussion for a further improvement of the model, its limits in the application.
JSP23/W/89-B1 Poster 0830-10
UNFAMILIAR HORIZONTAL WAVES IN UPPER LAYERS EXCITED BY ACCELERATION AND OTHER EFFECTS
GALIEV
Abstract not available at the time of going to press
JSP23/C/U5/E/18-B1 Poster 0830-11
LAVINA - A COMPUTER TOOL FOR AVALANCHE FORECASTER
Pavel CHERNOUSS and Evgeny Mokrov (Center of Avalanche Safety, "Apatit" JSC, 33a, 50 years of October St., Kirovsk, Murmansk region 184230, Russia, e-mail: P.Chernous@apatit.murmansk.su); Alexander Perlikov (Institute of Ecology, Kola Science Centre of the Russian Academy of Sciences, 14a, Fersmana St., Apatity, Murmansk region 184200, Russia)
LAVINA is a software package which assist avalanche forecaster to evaluate avalanche risks. It is an integrated system consist of two main units permitting evaluate probabilities of avalanche occurrence and dynamical parameters of possible avalanches. Probability of avalanche occurrence is evaluated for a whole region or for a separate starting zone. In the first case standard meteorological data and snow drift measurements are used for different types of discriminant analysis and pattern recognition algorithms. Diagnostics is carried on each third hour as current measurements have being made. Probabilistic and categorical conclusions on avalanche releases are the results of data treatment. There is an opportunity to display ten situations closest to current one from archive. Statistical simulation applied to snow thickness, density and shear strength is used for evaluation of snow cover stability in a separate starting zone. The areas of instability of different probabilities are displayed at a computer monitor. The dynamical parameters of a probable avalanche – maximal speed and impact pressure, are calculated at any given point of the avalanche path. LAVINA as a part of computer assisted work place of an avalanche forecaster is in operation at the Center of Avalanche Safety since 1991. The results of its exploitation are discussed and the ways of its improving are considered.
JSP23/E/52-B1 Poster 0830-12
INFLUENCE OF MACROSEISMIC INTENSITY ATTENUATION IN SEISMIC HAZARD EVALUATION FOR FAGARAS (ROMANIA) CRUSTAL SOURCES
IREN-ADELINA MOLDOVAN (IVAN) and Aurelian Pantea (National Institute for Earth Physics, P.O. Box MG-2, Bucharest-Magurele, Romania, e-mail: pantea@infp.ifa.ro and iren@infp.ifa.ro)
An important step for the correct assessment of seismic hazard is the interpretation of the macroseismic effects distribution from a given seismic zone, as well as the good evaluation of seismic intensity attenuation laws. The attenuation was analysed as a function of distance and azimuth, using nine attenuation laws.
The present paper is a study of macroseismic intensity attenuation laws, using 5 crustal earthquakes (MGR>4.0) occurred in Fagaras(Romania) seismic zone, along the following azimuths: E, W, N,S,NE,SW,NW,SE. The evaluation of macroseismic intensity attenuation laws for Fagaras region was imposed by the necessity of seismic hazard assessment in this high seismic potential zone the largest event occurred in this zone: MGR =6.4; Io=IX).
JSP23/W/90-B1 Poster 0830-13
COMPARISON BETWEEN TWO SYSTEMS OF BASE SEISMIC INSULATION
Federico BARTOLOZZI (Civil Engineer and Independent Researcher, via dei Carracci3, 21100 Varese, Italy, email: ciuciuzza@iol.it)
One of the proposed systems is with four rigid movable bearings and the other one with four elastic bearings. The two systems share the following characteristics: 1. self-centring of the building after an earthquake; 2. extreme economical competitiveness with all the existing anti-seismic systems, due to the considerable decrease of the seismic energy in the building, which makes possible the use of slenderer carrying structures. The differences between the above systems are: 1. a pendulous effect in the building, during an earthquake, in the system with rigid bearing. It is characterised by a very small vertical rotation of the building, which varies in average from a few seconds to some minutes with soil displacements included between some millimetres and about 150 mm. In addition, this effect is extremely limited and has no repercussions of psycho-physical character for the inhabitants of the building; 2. the verticality and the immobility of the building with respect to the horizontal translation of the foundation-soil complex n the system with elastic bearings. The vertical elastic strain of the springs compensates the variations of rigid deflection relative to the bearings, due to the inclination of their sliding surfaces. The vertical component of the of the motion, due to the sub-undulatory shock, varies only partially the building behaviour because of two phenomena: minor vertical translation of the building and resonance possibility. In order to prevent the resonance danger, each bearing is equipped with two or four frequency converters automatically started up when the emergency situation, defined by the equality between the vertical component of the earthquake frequency an the building vertical natural frequency, becomes imminent.
JSP23/C/U5/W/05-B1 Poster 0830-14
HIMALAYS CRUST DEFORMATION REGION, RADON EMANATION AND SEISMO WAVE EFFECTS
Vladimir ALEXEEV, Yury Mikhailov (Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation of Russia’s Academy of Science, Troitsk, Moscow region, 142092, Russia,
e-mail: yumikh@charley.izmiran.rssi.ru)
The Himalays form is available region for study of the deformation processes of continental crust during collision orogeny. Simple shear dominant strains have developed new fabrics parallel to the main thrust zone. Radon fields [1] and aerosols create anomalous electric fields, which may change properties of upper wall of wave-guide earth ionosphere. This process leads to change of penetration of ELF-VLF waves through lower ionosphere and evolution of spectral characteristics of electromagnetic emissions, registered on satellites [2].
1 Virk H.S., Singh B. Correlation of radon anomalies with earthquakes in the Kangra Valley. Nucl. Geophys. 1992 V.6. N2. P.293-300.
2 Yu.M.Mikhailov, G.A.Mikhailova, O.V.Kapustina. Relation between ELF and VLF emissions on the Intercosmos 24 satellite and concentration of radon in earthquake regions. SSA 15 /GA 118 report of XXII IUGC General Assembly
JSP23/W/34-B1 Poster 0830-15
PHENOMENOLOGICAL MODEL OF THE LARGE-SCALE EVOLUTIONARY PROCESSES IN A HAZARD SYSTEM OF THE EARTHQUAKE BASED ON THE SOC (SELF-ORGANIZED CRITICALITY) CONSIDERATION
Natalia SMIRNOVA, Vladimir Troyan (Institute of Physics, University of St.Petersburg, St.Petersburg 198904, Russia, e-mail: nsmir@snoopy.phys.spbu.ru); Masashi Hayakawa (The University of Electro-Communications, Chofu, Tokyo 182, Japan, e-mail: hayakawa@whistler.ee.uec.ac.jp); Thomas Peterson (TFPLAB, Cleveland, Ohio 44124-5441, U.S.A., e-mail: TFPLAB@aol.com), and Yury Kopytenko (St.Petersburg Filial of IZMIRAN, St. Petersburg 191023, Russia,
e-mail: galina@admin.izmi.ras.spb.ru)
The concept of self-organised criticality (SOC) is now widely used for interpretation of the natural hazard system behaviour. That concept was included as one of the principal point in a complex approach proposed recently by the present authors for searching the earthquake precursory signatures. Here we develop consideration of the processes in the earthquake regions on the basis of SOC concept. We suggest a phenomenological model for large-scale evolutionary processes occurring between two violent earthquakes. Four principal phases of the evolution: random chaos, subcritical, critical and supercritical stages are proposed and analysed consistently. The external stimuli such as geomagnetic storms, sharp temporal and spatial variations of atmospheric pressure, ULF impulses and others are considered as a driving force for "cellular automata" process in a seismoactive region. The important fingerprints of SOC - fractal structures in space and time are analysed using seismicity data and the ULF electromagnetic data timed to violent earthquakes near Guam (August 8, 1993, M = 8.0) and Kobe (January, 16, 1995, M = 7.2). A possibility to use the fractal characteristics of signals to study critical dynamics of a hazard system is discussed.
The research was supported by NASDA (Japan) and Russian Foundation for Basic Research (Grants No. 98-05-65554 and 99-05-NNN).
JSP23/E/24-B1 Poster 0830-16
DYNAMICS OF SELF-DEVELOPING NATURAL PROCESSES AND PROSPECTS OF ITS USE FOR THE FORECAST OF GEOPHYSICAL CATASTROPHES.
Alexander I. MALYSHEV (Institute of Geology and Geochemistry, Urals Branch of RAS, Pochtovy per 7, Ekaterinburg, SU-620151, Russia, email root@igg.e-burg.su)
Study of patterns of fore-culmination activizations present a great interest for the forecast of geophysical catastrophes, such as disastrous earthquakes, strong volcanic eruptions, rock bumps, landslides etc. During the study of Bezymyannyi volcano eruptions in 1980-1987 the fact of hyperbolic activization before explosive-effusive eruptions was established. Further studying of the revealed regularities and their comparison with empirical dependencies of the development of various natural processes allowed to conclude that there is a wide class of self-developing natural processes, the dynamics of which is described by non-linear differential equation of the second order. The attempts of using these regularities for the forecast of eruptions were quite successful, however the accuracy of the forecast for the time of eruption did not exceed a semi-quantitative level. At present the methods, allowing confidently to reveal the laws of the development of natural processes, have been developed. As it is shown on the example of a number of Bezymyannyi and Shivelutch volcanic eruptions, for the class of eruptions, having stable fore-culmination preparation, this technique allows increasing accuracy of paroxysm time forecast up to a quantitative level.
The forecast of destructive earthquakes is more complicated. Ivan Tikhonov and me have analyzed the fore-shock-aftershock sequences of destructive earthquakes in southern Kuril arc area. It was established that the development of both of fore-shock, and aftershock sequences corresponds to the equation of the dynamics of self-developing natural processes. However the fore-shock sequences are more poorly expressed. Probably, some updating of seismic observations is required for getting more stable results. The obtained results make it possible to assume that the methods are a perspective for the forecast of these geophysical catastrophes.
Tuesday 27 July AM
DETECTION, MONITORING,EARLY WARNING AND PREDICTION
JSP23/W/25-B2 Poster 0830-01
EXCESS AND DEFICIENT RAINFALL YEARS OVER INDIA DURING 1871-1996: A
BRIEF APPRAISAL
A. A. MUNOT (Indian Institute of Tropical Meteorology Dr. Homi Bhabha Road, Pashan, Pune-411 008, India, e-mail: munot@tropmet.ernet.in)
India, being an agricultural country has its economy closely linked with the performance of the summer monsoon (June-September) which gives 75-90 % of the total annual rainfall. Timely onset and normal distribution of rain in the summer monsoon season generate good amount of food production whereas erratic behavior of monsoon which leads to drought/flood over the country has an adverse effect on the food production and in turn on the economy of the country. Because of this, year to year variation of monsoon rainfall becomes the subject of immense importance. In view of this in this paper an attempt is made to study the inter-annual variability of summer monsoon rainfall for the period 1871-1996. On an average India as a whole receives 852.4 mm of monsoon rainfall with a standard deviation of 84.7 mm and coefficient of variation of 9.9 %. Excess and deficient rainfall years over the country are identified using suitable criterion. There are 22 deficient and 19 excess rainfall years during 1871-1996. The total area of the country under deficient rainfall conditions as well as under excess rainfall conditions have been computed for all the deficient/excess rainfall years. The mean area of the country under deficient rainfall condition in a deficient rainfall year is found to be 42.8% whereas the mean area of the country under excess rainfall condition in a excess rainfall year is found to be 35.7 %. Out of 22 deficient rainfall years, during four years viz. 1877, 1899, 1918 and 1987 more than 60 % area of the country suffered from deficient rain. Similarly out of 19 excess rainfall years during four years viz. 1892, 1917, 1961 and 1988 more than 40 % of the total area of the country was under excess rainfall conditions. Conditional probabilities have been computed for all-India rainfall to be deficient or excess on the basis of June, July and June + July rainfall. It is observed that by the end of July it is possible to anticipate with reasonable degree of accuracy how the performance of the monsoon will be at the end of September, whether it will be normal, deficient or excess. Based on these assessments precautionary measures can be taken in case of monsoon being abnormal.
JSP23/C/U5/E/11-B2 Poster 0830-02
SHORT-TERM EARTHQUAKE PREDICTION: METHODOLOGICAL ADVANTAGES AND WARNING SYSTEM.
Vitali A. MORGOUNOV (Institute of Physics of the Earth, Moscow 123810, B.Grusinskaya 10, Russia, email vam@uipe-ras.scgis.ru)
What is preferable: to use a chance to win or full ignorance of impending hazard?! Are the cases of real predictions only a blind luck or it is a step to solve the problem? At what extend the uncertainty relation Cognoscibility/Unpredictability of Earthquakes could be improved? Between polar opinions like the dismal prospects for real improvement of the unpredictability (London, November. 7-8, 1996) and unique practical success in China in 1975,1997 there exist a optimum way to solve the most important part of the problem. Progress in the study of short/immediate precursors could be one of the possible path to get over the obstacle due to the following advantages. 1. The final stage of preparation of impending earthquake is characterised by a substantial activation of the process while it's strain rate increase by the orders of magnitude and considerably increase signal-to-noise ratio. That is favourable for identification of critical state of the focal zone through the ground measurements of geophysical fields, in particular by electromagnetic emission, generated by the stress-strain rate of the rock. 2. The avalanche creep process and the worked out instrument make possible to advance the effectivity of the method in relatively short period of time in seismic active areas during the background seismicity (M=3-4). 3. The short-term methods suggest the practical utilisation to prevent the casualties and ecological catastrophes. The EM method, experimental results, and Hardware-Software System "Alarm-Seismo" as an acceptable warning instrument are discussed. The System consists of the network of N slave controllers and master station, where in a real time regime the data is processing by PC computer. The distance between the slave stations is defined by the magnitude of expected earthquake, tectonic and geological peculiarities of the region, relief.
JSP23/W/99-B2 Poster 0830-03
MONITORING OF NATURAL HAZARDS USING MULTI-SENSOR DATA
Ramesh P. SINGH, Sudipa Roy and N.C. Mishra (all at Department of Civil Engineering, Indian Institute of Technology, Kanpur - 208016, India, email: ramesh@iitk.ac.in)
The data recorded by the Special Sensor Microwave Imager (SSM/I), IRS-P3 MOS, IRS - LISS and NOAA AVHRR Data over India have been analysed. The brightness temperature deduced from SSM/I data over snow covered region show distinct behaviour which is attributed to the variable snow thickness and snow melting. The routine analysis of SSM/I data will give fairly good idea of snow avalanches and flooding of the river as a result of snow melting. The daily or weekly variations of brightness temperature, liquid water path (LWP) and total precipitable water (TPW) over Arabian sea and Bay of Bengal has given an anomalous characteristics of a tropical cyclone which hit the coast of Bangladesh. The normalised vegetation index (NDVI), vegetation condition index (VCI) and temperature condition index (TCI) deduced from NOAA-AVHRR give information about the vigor of the vegetation which can be used in monitoring of drought conditions. The IRS-P3 MOS data in 14 bands along path 95 of winter and summer seasons have been used in classifying water bodies. The spectral reflectance deduced in 14 bands give information about the water quality> The characteristic peaks in the spectral reflectance data give idea about the type and distribution of contamination in water bodies. The IRS-LISS data has been used for mapping of the lineaments which can be used for the evaluation of seismic hazards of any region. In the present paper the use of multi sensors data will be illustrated and discussed in monitoring various types of natural hazards.
JSP23/W/100-B2 Poster 0830-04
GEOPHYSICAL HAZARDS: MITIGATION AND WARNING SYSTEMS IN INDIA
K.S. MURTY (E-3 Vishnukamal Apts., 160 Shivajinagar, Nagpur, 440 010 India)
In the last two decades, India was hit by several natural disasters of which the Andhra cyclone of 1977, the Uttarkashi earthquake of 1991, the Latpur earthquake of 1993 and the Andhra cyclone of 1996 are typical geophysical phenomena that caused destruction of property and loss of life on a large scale. Relief measures were taken up by government and non-government agencies, while long-term measures like construction of cyclone shelters and new villages to house the affected population were intiated. Cyclone warning systems, flood warning systems, and seismological network in areas that are prone to these geophysical hazards have been set up. Besides, improved infra-structures like road construction have been made part of the development programmes of the concerned areas. These steps have considerably reduced loss of life in some of the more recent natural disasters the country faced.
JSP23/E/12-B2 Poster 0830-05
AN EMPIRICAL DISPERTION RELATION FOR SEISMIC SIGNALS AND EARTHQUAKE PREDICTIONS
Boris W. LEVIN (Shirshov Oceanology Institute of RAS and Russian Foundation for Basic Research, 32a Leninsky prosp, Moscow, 117334 Russia email: levin@rfbr.ru); Elena V. Sassorova (State Oceanographic Institute, 6 Kropotkinsky per., Moscow, 119838 Russia; sasor@geoph.ioras.msk.ru)
We show that faint seismic signals radiated from an earthquake source and acoustic signals foregoing a compression failure of laboratory rock samples can be written by common empirical relationship for waves of period T and length L, as follows T^2 = d L, where d is dimension coefficient. This leads us to some empirical dispersion relation for seismic signals that is defined by expression W^2 = 2*3.14* A k, where W is frequency, k – wave number, A- acceleration of stress force. The attempt to find such dispersion relation with theoretical way was made by L.Brevdo (1998) because similar function may, on his opinion, lead to an effective method of some earthquake prediction. We used special developed software package for data processing of 200 earthquake records and had found more than 30 events in which digital records the seismic foregoing signals were discovered. The period-length relation for these signals was well described by presented expression. Although the expression should been studied for using in condition of real seismic region, the presented method can sometimes be used to further improve earthquake disaster mitigation practices.
JSP23/C/U5/W/04-B2 Poster 0830-06
A VOLCANO MONITORING AND TSUNAMI WARNING SYSTEM FOR GRENADA AND THE SOUTHERN GRENADINE ISLANDS.
Lloyd L. LYNCH, John Shepherd, and Chandradath Ramsingh (Seismic Research Unit, University of the West Indies, St. Augustine, TRINIDAD, email: sru@wow.net).
We propose to develop and establish a volcano monitoring and tsunami warning system for Grenada and the southern Grenadine islands. This region is located close to the Kick 'em Jenny (KeJ) submarine volcano, which has erupted ten times since it, was first identified in 1939. Studies that have been done to assess the explosive potential of this volcano and to assess the vulnerability of the East Caribbean Islands to tsunamis, have identified it as a prime tsunami-genic source with Grenada and the southern Grenadines being most vulnerable to its hazards. The studies have also revealed that East Caribbean islands are exposed to tsunamis from other potential sources but to a lesser extent and that the existing regional seismograph and volcano monitoring efforts could be extended and reinforced to mitigate the effects of hazards from KeJ and tsunamis.
The primary aim objective of the volcano monitoring and tsunami warning system is therefore to maximise life safety by providing some level of advanced warning to the vulnerable population. The system is composed two critical components. The first is an integrated network of instruments to detect and rapidly evaluate the nature of increased volcanic activity at the KeJ and events of tsunami generating potential (such as sub-marine landslides or large earthquakes). An array of tide gauges will also be used to track the progress of any sea wave that may be generated. The second component of the system is a set of definitive procedures on how to respond to a tsunami-genic event. All data from the network will be tele-metered to a permanently manned monitoring and warning center to be established near the north coast of Grenada. Warning and alert activities will be co-ordinated through this center. Selected data channels will be relayed to the headquarters of the regional earthquake and volcano-monitoring agency - the Seismic Research Unit (SRU). This agency will widely support the warning center in the areas of equipment installation and maintenance, data processing and interpretation, and staff training. The SRU also plans to assist in educating vulnerable communities about other mitigation techniques that can be used to complement the proposed system.
JSP23/E/49-B2 Poster 0830-07
TOWARDS UNDERSTANDING LAHAR-TRIGGERING MECHANISMS AT RUAPEHU
Vincent NEALL and Jerome Lecointre (Institute of Natural Resources, Massey University, Private Bag 11 222, Palmerston North, New Zealand, email: V.E.Neall@massey.ac.nz); Katy Hodgson (Natural Resources Engineering/Environmental Management and Design Division, Lincoln University, P.O. Box 84, Canterbury, New Zealand, email: Hodgsonk@kea.lincoln.ac.nz)
Over 20 major lahar deposits have been mapped and described from the past 2,000 year B.P. record at Ruapehu. In historical time, a number of different lahar-triggering mechanisms have been observed, so it is pertinent to ascertain how the prehistoric lahar record originated and how this relates to lahar magnitude. We are beginning to recognise specific signatures in the lahar/tephra record that fit models for lahar generation at this volcano. Lahar deposits immediately preceding tephra eruptions are consistent with volcanic activity emptying the crater lake until dry eruptions can occur with resultant ash showers as exemplified by the 1995 eruptions. Lahar deposits immediately following tephra eruptions are consistent with post-eruptive rain-triggering events mobilising tephra accumulations high on the cone. Lahar deposits containing fragile volcanic bombs are clearly indicative of explosion events and eruption-generation of the lahars. Others will be non-eruptive collapse events due to failure of the crater lake wall for a variety of reasons. Currently our programme seeks to: (1) use all sedimentological parameters to characterise the lahar deposits; (2) use petrological matching of lahar clasts to lava flows on the edifice; (3) integrate the complex lahar and tephra record and; (4) provide further precise dating, to elucidate how prehistoric lahars over the last 2,000 years were generated. We thereby hope to understand the environmental conditions one may expect to lead to, or cause any future laharic event.
JSP23/W/27-B2 Poster 0830-08
ERUPTION FORECASTING AT CERRO NEGRO VOLCANO, NICARAGUA, USING TIME-VOLUME RELATIONSHIPS
Brittain HILL, Charles Connor (CNWRA, Box 28510 San Antonio TX USA 78228,
E-mail: bhill@swri.edu)
At the scale of sub-duction-zone tectonics, magma production rates appear constant relative to eruption recurrence rates. Differentiation and mixing processes obscure magma production rates in the mantle, making time-volume relationships complex at differentiated volcanic systems. Cerro Negro (CN) volcano in Nicaragua, however, has erupted relatively homogeneous high-Al basalt 22 times since forming in 1850 A.D. Small petrogenetic variations at CN are produced through minor crystal fractionation+accumulation. Waxing activity from 1850-1900 is followed by a steady-state eruption rate of 1.8x10^6 m^3/yr. Relatively constant petrogenesis of CN basalt suggests eruption rate is controlled by the mantle replenishment rate and thus may follow simple time-volume predictable patterns. Empirically, large-volume eruptions at CN since 1900 are followed by long quiescence, whereas short quiescence follows small-volume eruptions. The timing of CN eruptions >5x10^6 m^3 has a linear relationship (r^2=0.97) with cumulative volume at the time of each eruption. Eruptions in 1992 and 1995 are successfully forecast within 1 yr of the actual eruption using these relationships. The 1971 eruption occurred 12 yr earlier than expected, also earlier than forecast using a 95% confidence interval (1973-1996). The 1968 eruption occurred 8 yrs
JSP23/E/23-B2 Poster 0830-09
GEODETIC MONITORING OF FOGO ISLAND (CAPE VERDE ARCHIPELAGO) FOR VOLCANIC HAZARD REDUCTION
Sandra I N HELENO, Joao L Matos and Joao F B D Fonseca (IST, Av Rovisco Pais, 1, 1049-001 LISBOA, Portugal, email: sisilva@alfa.ist.utl.pt); Jos N P Lima and J P Osorio (Centro de Geodesia, Instituto de Investigacao Cientifica e Tropical, Rua da Junqueira, 534, 1300 LISBOA, Portugal,
email: cgeod@www.iict.pt); Inocencio J M Barros and Arlindo Rosario (LECV, CP 114, Praia, Republic of Cape Verde, email: lec.mit@mail.cvtelecom.cv); Antonio Berberan (LNEC, Av. Brasil, 101, 1799 LISBOA, Portugal, email: berberan@lnec.pt); Simon J Day, Benfield Greig Hazard Research Centre, UCL, Gower Street,London WC1E6BT, UK, email: s.day@ucl.ac.uk)
As part of a broader hazard reduction project in Fogo Island, N Atlantic, (Fonseca et al., this issue), a programme of periodic GPS and levelling observations was initiated, with a view to the forecasting of impending eruptions by the detection of associated anomalous crustal deformations. In addition, the data will be used in the characterization of the possible flank instability of the volcanic edifice (Day et al., this issue), which may in itself constitute a significant hazard to the population of the island (33000 inhabitants).This poster describes the observational infrastructure built in the island (23 observation points), emphasising the volcanological criteria behind its design, the care taken in the selection of sites with adequate geology, and the stability requirements of the monuments. Results from the Zero Epoch campaign (September 98) are presented and discussed earlier than forecast, but within a 95% confidence interval (1967-1994). Several intervening small-volume eruptions before the 1968 and 1971 events likely triggered the larger eruptions before source replenishment was complete. The 8x10^6 m^3 of basalt erupted during 1995 activity at CN indicates the next significant eruption is most likely in 2000+/-1, with a 95% confidence interval to 2006 in the absence of intervening small-volume eruptions.
The work reported here was supported by the U.S. Nuclear Regulatory Commission (Contract NRC-02-97-009). This work is an independent product of the CNWRA and does not necessarily reflect the views or regulatory position of the NRC.
JSP23/E/50-B2 Poster 0830-10
GLOSEISRISK: A SIMPLIFIED APPROACHING TOOL FOR GLOBAL SEISMIC RISK
QI-FU CHEN and Jie Liu (P. O. Box 166, Center for Analysis and Prediction, CSB,Beijing 100036, P. R. China, email: cqf@ip.cap.ac.cn); Yong Chen (No. 63, Fuxing Avenue, China Seismological Bureau, Beijing 100036, P. R. China, e-mail: yongchen@public.bta.net.cn); Ling Chen (Institute of Geophysics, CSB, Beijing 100081, P. R. China)
A simplified methodology of seismic hazard and risk assessment has been developed by IASPEI working group chaired by Prof. Yong Chen. The new approach includes two analysis methods: One is the seismic hazard analysis method by using earthquake catalogs as basic data and taking area model as potential earthquake sources. A technique is also developed providing the method for integrating individual influences of area sources, near and far, more active or less, into the probability distribution of seismic intensity or peak ground acceleration. Second method addresses exposure bypasses the data collection problems of the traditional method by employing a macroscopic indicator to represent the total exposure directly. The earthquake losses are assessed quickly and approximately by using social wealth represent by Gross Domestic Product and population data.
GloSeisRisk is application software based on Geographic Information System, which is designed to perform analysis and demonstration of seismic hazard and risk with the simplified methodology. The GIS-based GloSeisRisk offers a simplified approach modeling earthquake hazard assessment, loss estimation and earthquake scenario analysis. The GloSeisRisk includes the data analysis and processing programs for seismic catlogue, GDP and population and the seismic risk estimation functions respectively. It can also illustrate the data distribution and seismic risk maps for different print output. The data can be updated readily from available resources in this application tool and easy to update seismic risk analysis.
JSP23/C/U5/E/21-B2 Poster 0830-11
SCIENCE OR CHANCE? SCORING THE CHINESE ANNUAL EARTHQUAKE PREDICTION FROM 1990 TO 1997
Yaolin SHI (Graduate School, University of Science and Technology of China, Academia Sinica, Beijing 100039, China, email: shiyl@sun.ihep.ac.cn); Jie Liu and Guomin Zhang (Center for Analysis and Prediction, Chinese Seismological Bureau, Beijing 100036, China, email: liujie@cap.ac.cn)
China is the only country in the world that has an official institution dedicated to precursor monitoring and earthquake prediction. About 800 observational stations spread over China, where more than 1700 pre-cursorial elements are monitored on regular basis. Every January, the Chinese (State) Seismological Bureau holds a national consultation meeting on prediction of major earthquake of the year. Deterministic predictions are made in the meeting. Possible risk areas for the year are circled out. These predictions are reported in official documents to the State Council, though kept confidential during the predicted year to avoid unnecessary social panic. In this study, we apply a scheme of success rate score (R-score) to evaluate the disclosed annual predictions in the 90s. A random guess leads to an R-score of 0 and a complete successful prediction has an R-score of +1. The average R-score of the annual prediction in China in the 90s is about 0.10. The probability in achieving equal or better results by random guess for an averaged year is quite high, about 1/3. However, the probability for random prediction to get equal or better scores in 8 successive years is very low, only 1.5X10^-4. In conclusion, we believe that earthquake prediction in China is not by chance, even though it is still in a very preliminary stage to fit the definition of science.
JSP23/E/35-B2 Poster 0830-12
CONTRIBUTION OF GEOPHYSICAL INVESTIGATION TO SOLVE AN ENGINEERING PROBLEM, SOUTH EL-KHARGA OASES, EGYPT
Maher A. MESBAH (Department of Geological and Geophysical Engineering; Faculty of Pet. and Min. Eng., Suez, Suez Canal University, e-mail: mmesbah@frcu.eun.eg)
A severe subsidence in the ground has been occurred during the passing of heavy machines which are used in the foundation processes of the base and the sub-base of El-Kharga-Paris railway proposed site. The current geophysical study is directed to determine the causes of this civil engineering problem. Therefore, geoelectric resistivity measurements were done by measuring 25 vertical electrical soundings (VESes) along the proposed line. Also, the previous regional gravity and magnetic surveys were examined in order to obtain the maximum information content from the measured resistivity soundings. In the light of the previous geological, geophysical and geotechnical studies in the area, the measured VESes were manually and automatically processed and interpreted in the light of the drilled boreholes. The analysis and the interpretation of the obtained results should that the maximum monitored depth is 42 m. The resulted geoelectrical models reflects that 3 to 4 geoelectric layers can be determined. A dry surface inhomogeneous layer formed from alluvium deposits covers the investigated site. This surface layer is followed by a soft to hard clay layer. The second geoelectric layer is followed by a hard and compacted clay layer and it was monitored at the most of VESes and didn’t at some of them. Therefore, the bedrock layer needed to be a sub-base (or a base) for foundation didn’t monitored along the investigated site and special construction requirements are necessary to overcome this conditions of the base.
JSP23/E/36-B2 Poster 0830-13
AUSTRALIA'S IDNDR PROGRAM FOR MITIGATION OF GEOPHYSICAL HAZARDS
Jack RYNN (Member Australian IDNDR Co-ordination Committee, Centre for Earthquake Research in Australia, PO Box 276, Indooroopilly, Queensland 4068, Australia. email: sally.brown@uq.net.au); Alan Hodges (Chair Australian IDNDR Co-ordination Committee, Director General Emergency Management Australia, PO Box 1020 Dickson, ACT 2602, Australia. Email: ahodges@ema.gov.au); Pip Marks, (Manager Australian IDNDR Coordination Committee, Emergency Management Australia, PO Box 1020 Dickson, ACT 2602, Australia. Email: pmarks@ema.gov.au)
Following the proclamation by the United Nations of the International Decade for Natural Disaster Reduction (IDNDR) 1990 - 2000, the Australian Committee was established within Emergency Management Australia (EMA) to pursue the ideals and goals of IDNDR pursuant to mitigation measures of natural disasters in Australia. More than 120 projects were successfully undertaken directly relating to the IDNDR targets of risk assessment, mitigation measures (awareness, disaster planning, education, dissemination of information, community involvement) and warning systems, natural hazards. The multi-disiplinary approach involved government agencies (national, state and local), NGO's, academia and the private sector. The Australian projects include tropical cyclone workstation, risk assessments for storm surge and tsunami, earthquake mitigation of cities, flood and landslide awareness, wildfire prediction and warnings, economic guidelines for loss reduction, medical training package, media campaigns, education curricula and community awareness campaigns. Co-operative efforts with 7 Pacific Island countries through the Pacific Region IDNDR (per 1994 Yokohama Statement) completed projects on cyclone, flood, earthquake, tsunami, landslide and volcano. Planning is in progress to continue the IDNDR concept into the 21st century.
JSP23/E/27-B2 Poster 0830-14
VIGIL - A WARNING SYSTEM FOR VOLCANIC ERUPTIONS IN FOGO ISLAND, NORTH ATLANTIC
Joao F B D FONSECA and Sandra I N Heleno (both at Physics Department, IST, Av Rovisco Pais, 1, 1049-001 LISBOA, Portugal, email: fonseca@alfa.ist.utl.pt) Peggy Hellweg and Horst Rademacher (both at Geo Enterprises Orinda, 57 Overhill Road, Orinda, CA 94563-3122, USA,
email: HRademacher@compuserve.com) Steve Pauly and Bruce Pauly (both at Digital Technology Associates Inc, USA, 1330A Galaxy Way, Concord, CA94520, USA,
email: dta_pauly@compuserve.com) Nicolas dOreye (ECGS, Walferdange, G.D.L.,
email: nicolas.doreye@ecgs.lu) Inocencio J M Barros and Arlindo Rosario (both at LECV, CP 114, Praia, Republic of Cape Verde, email: lec.mit@mail.cvtelecom.cv)
The low-energy strombolian eruption of April 95 in Fogo Island (North Atlantic), following 44 years of quiescence, enhanced the awareness of the risk posed to its 33.000-strong population by the volcanic activity (average interval between eruptions of about 20 years). This created the conditions for the implementation of a volcanological monitoring routine, presently being tested.
This presentation will describe the main components of the monitoring instrumentation, namely, a combined network of broad-band (Guralp CMG-40T) and short-period (Guralp CMG-40T-1) seismic stations, and a network of resistive tiltmeter (AGI702) stations. All the data collected, both in Fogo Island and in the neighbouring Brava Island, are transmitted in realtime to the data acquisition and processing laboratory (located in Praia, Santiago Island) using spread-spectrum transceivers and combiner-repeater modules. Aditionally, a network of 23 high-precision geodetic monuments was built in Fogo Island to allow the periodic surveying with GPS receivers and EDM.
JSP23/C/U5/W/01-B2 Poster 0830-15
SPACE - GEODETIC MONITORING OF LANDSLIDE MOVEMENTS USING GPS TECHNIQUES
P.RUTIGLIANO, F. Vespe (Centro di Geodesia Spaziale P.O. BOX Aperta, 75100 - Matera ITALY, email: rutigl@asi.it); F. Cafaro, C. Cherubini (Politecnico di Bari - Istituto di Geologia Applicata
e Geotecnica, Via Orabona 4, 74100 Bari, Italy)
The use of GPS techniques in monitoring natural hazards like volcanic deformations or landslide motions can be a powerful way to improve disaster mitigation. In this work the experimental setting up of a GPS-based system able to monitor landslide motions is reported. The first step of this work consists in evaluating how much a small simulated landslide movement can be mirrored by GPS data. The landslide simulation has been necessary to calibrate the hardware and the software used in this analysis. The experiment has been done using an array of six receivers placed in a small area around the CGS (Center of Space Geodesy) near Matera, Italy. One receiver has been assumed as reference, working permanently during the whole campaign. The other sites have been occupied for eight hours three times each, in order to obtain an evaluation, of the baseline length between all the receivers and the reference one before and after the displacement of the antenna of a known quantity (few cm). The main topics under investigation in this step have been:
a) The minimum observation time needed to obtain an estimation accuracy level suitable to this application (2-3 cm)
b) The possibility of using one frequency (L1) instead of two frequency (L1/L2) GPS receivers without loss of accuracy in the estimation of the movements
The second step of the work consists in the planning of a system to constrain solidly the GPS antenna to the ground, necessary to be sure that the possible motions detected with the GPS are representative of the real motion of the landslide.