The Giant, Underestimated Earthquake Threat to North America

The Giant, Underestimated Earthquake Threat to North America

(Excerpt:) The enormous fault off 
the coast of the Pacific Northwest has been silent for three centuries. But after years of detective work, geologists have 
discovered that it can
 unleash mayhem on 
an epic scale.

Exactly the same is true of the Cascadia subduction zone—an almost identical geologic threat off the west coast of North America. When it was first discovered, many scientists thought Cascadia’s fault was incapable of generating giant earthquakes. Now they know they were wrong. They just hadn’t looked far enough into the past.

The Cascadia subduction zone is a crack in the Earth’s crust, roughly 60 miles offshore and running 800 miles from northern Vancouver 
Island to Northern California.

http://discovermagazine.com/2012/extreme-earth/01-big-one-earthquake-could-devastate-pacific-northwest/article_view?b_start:int=1&-C=