Ya know, if we'd nuked Seattle back in '45...
When I was researching the Cascadia Subduction Zone about 15 years ago, I talked with Dr. Frank Gonzales of U. of Washington. He told me that geologists and seismologists had found beach sand as far inland as 11 miles up river channels on the Oregon and Washington coasts. The Indian tribes in the area have oral histories that describe how inland Indians went to the coast and found that the coastal villages and people were simply not there.
Dr. Gonzales said that (at that time) there were two working theories about the "big one" that was due; one was that the "big one" would be a magnitude 9 quake that would shake the region for up to 45 minutes, the other was what he described as "the decade from hell" in which the region would be wracked with mag. 8 quakes periodically for about a decade. Either way, it's potentially quite bad. It will make hurricane Katrina look like a tailgate party by comparison.
Nope. There exists geologic evidence of tsunamis along the Pacific Northwest coastline, and they were very, very big ones, too.
I live in southwest Washington, 800 ft. above the Columibia River and fifty miles from the Pacific.
My only fear about a large subduction earthquake is that it might happen during the wettest part of the year. Landslides due to water-ladden hillsides collapsing would kill a great many people and block highways preventing disaster relief.