Next Monday, the City Council is scheduled to get a briefing on the U.S. Geological Survey‘s latest scientific analysis of earthquake hazards in Seattle. The briefing slides have just been published along with the meeting agenda – see the presentation here. It’s part of an every-six-years process to update the hazard maps so that building codes (etc.) can take the conditions into account. Here’s the big headline:
That said – the Seattle Fault is the one closest to West Seattle, and the presentation says the chance of an earthquake stronger than magnitude 6.5 on that fault in the next 50 years is about 5 percent. The rate of that kind of earthquake anywhere around Puget Sound in the next 50 years is about 15 percent. As for a mega-quake on the coast somewhere, around 9.0 magnitude (akin to the one last year in Japan)? 10 to 14 percent chance of happening in the next 50 years. But don’t get complacent … if a 7.0-ish quake happened on the Seattle Fault, we’d be in the “extreme shaking” zone, per this scenario:
We’ll await Monday’s briefing (9:30 am at City Hall) for more context. But in the meantime, be sure you’re prepared – westseattlebeprepared.org can help (including the “Emergency Communication Hubs” – memorize the location of the one nearest you!).