Of couse, it didn't, and when I met a friend at a local pizzeria for lunch an hour or so later, I mentioned the source of my nonchalance. He was a Northwest native, and hadn't had anything like that casual response. The Nisqually was his first strong earthquake. Some level of earthquake awareness is the birthright of all West Coast dwellers, but I suppose that the first significant quake you live through is always more surprising and more frightening than you would have expected, no matter how much you thought you knew about them. It's a little like the tsunami evacuation route signs you see driving along the Pacific Coast, before the 2004 tsunami, they felt like speculative guesses at what coastal residents should do if a tsunami hits, but then we saw those images of the overwhelming power of a simple wall of water, and they communicated the vital urgency of knowing what to do when any sort of natural disaster happens.
In any case, later on that afternoon I went down to Pioneer Square, the old Seattle district defined by its masonry buildings and situated on loose, muddy soil. It was where the vast majority of the earthquake damage in Seattle happened. I somehow don't remember seeing much of that damage that day, maybe because the police had roped off the worst of it. (A week or so later, I did go back and see some of the collapsed brick walls and buckled pavement in the area.) I went over to Elliott Bay Books, the bookstore at the heart of the Square. The Pioneer Square Mardi Gras riots had happened early on the morning of the 28th, with at least one shooting and some buildings looted, and I remember telling one of the bookstore staffers that "its been an interesting 24 hours around here."