Wednesday, November 25, 2009
West Coast Dog's Breakfast
Nobody has a clue what is going to happen there, but many try to step up to the plate. Most likely, it's the Cascadia subduction zone that will slip down in a manner identical to the big 2004 Sumatra M9. Even though it slips on a shallow-dipping fault that goes under the cities, the shaking will not be so big a deal. You would get a heck of a lot more from local M7's! What will be big is the tsunami and permanent elevation changes.
So, I think the main seismic hazard is from an urban M7, right under Seattle or Vancouver, or Portland. If you design for that, the 'Big One' is taken care of. (How long can you tread water? --Cosby).