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.Ci