Seismic threat to the Pacific Northwest

Abstract

Which region of the contiguous United States has the potential for the largest earthquake? Surprisingly, the answer may not be California. With the possible exception of the Alaska subduction zone, the Cascadia subduction zone, extending 1,200 kilometers from Northern California to Vancouver Island, is the largest tectonically active fault system in North America. The Cascadia subduction zone is currently gaining credence as a potential, major threat to Eureka, Portland, Seattle, and Vancouver. Because it is a relatively new focus of study, no existing building codes or regulations incorporate the force levels necessary to withstand a major event on the Cascadia zone. Design standards must be reevaluated to reflect and mitigate the catastrophic damage that could occur in the zone.