The San Andreas fault might be the sexier, more famous fault line predicted to destroy a sizable portion of the West Coast, but another running through the Pacific Northwest, featured in an article in this week’s New Yorker, is scarier: not only will it cause more damage and kill or injure tens of thousands of people, it will likely do so within the next 100 years, with a one in three chance it will happen very, very soon.
According to the seismologists interviewed by The New Yorker, the fault line, known as the Cascadia subduction zone, runs hundreds of miles between Northern California and ends around Vancouver, and is the area where the continental plates are doing something they are not supposed to do. Whereas a tectonic plate will normally slide underneath another plate—remember eighth-grade geology?—these are jammed up against each other in the Cascades, explaining why no one’s felt an earthquake in the Pacific Northwest, whereas, say, Japan gets a ton of them.
There is a backstop—the craton, that ancient unbudgeable mass at the center of the continent—and, sooner or later, North America will rebound like a spring,” the piece’s author, Kathryn Schulz, explains. “If, on that occasion, only the southern part of the Cascadia subduction zone gives way . . . 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.”
The less-scary earthquake will be the equivalent of the 2011 earthquake that devastated Japan, but the more-scary earthquake, which is about a hundred or so years overdue and has historical precedent . . . well, it’s going to look something like this:
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