How much longer can the West Coast avoid a catastrophic earthquake?

How much longer can the West Coast avoid a catastrophic earthquake?


The Really Big One
An earthquake will destroy a sizable portion of the coastal Northwest. The question is when.

...Most people in the United States know just one fault line by name: the San Andreas, which runs nearly the length of California and is perpetually rumored to be on the verge of unleashing “the big one.” That rumor is misleading, no matter what the San Andreas ever does. Every fault line has an upper limit to its potency, determined by its length and width, and by how far it can slip. For the San Andreas, one of the most extensively studied and best understood fault lines in the world, that upper limit is roughly an 8.2—a powerful earthquake, but, because the Richter scale is logarithmic, only six per cent as strong as the 2011 event in Japan.

Just north of the San Andreas, however, lies another fault line. Known as the Cascadia subduction zone, it runs for seven hundred miles off the coast of the Pacific Northwest, beginning near Cape Mendocino, California, continuing along Oregon and Washington, and terminating around Vancouver Island, Canada. The “Cascadia” part of its name comes from the Cascade Range, a chain of volcanic mountains that follow the same course a hundred or so miles inland...

...If, on that occasion, only the southern part of the Cascadia subduction zone gives way—your first two fingers, say—the magnitude of the resulting quake will be somewhere between 8.0 and 8.6. That’s the big one. If the entire zone gives way at once, an event that seismologists call a full-margin rupture, the magnitude will be somewhere between 8.7 and 9.2. That’s the very big one..."

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Southern California hasn't had a big earthquake since 1857. Here's what would happen if a mega earthquake hit California.


California is located in a hot-zone of fault lines that can rupture without warning.
Parts of the San Andreas fault have not ruptured in over 200 years, meaning it's overdue for a high-magnitude earthquake commonly referred to as "The Big One."
Here's what experts say could happen in seconds, hours, and days after the Big One hits the West Coast.

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