Since the magnitude 8.8 earthquake hit Chile last weekend, folks in the media have been talking a lot about how the Pacific Northwest could have a similar disaster.
I'd like to join in this chorus as a sort of public service announcement: some time soon an earthquake of around magnitude 9.0 -- and maybe several -- will strike the west coast of North America between Oregon and southern Canada. Depending on who you ask, we are either slightly or largely underprepared for this eventuality.
The science and scientists involved in monitoring the 680-mile long Cascadia megathrust fault is world class. It was only a few years ago that we learned the Cascadia is capable of hosting magnitude 9.0 earthquakes (and possibly greater ones), and that it last did so in 1700. Since then, scientists have established that the fault appears to break dramatically every 550 years or so, and that "silent" earthquakes add stress to the fault in periodic, 15-month cycles.
Still, no one can predict when the fault will break. The latest estimates suggest there is a 50 percent chance of a large earthquake off the coast of northern California or Oregon in the next 50 years. The odds of a quake situated next door to Seattle are about 1 in 4 during the same time period.
Make no mistake, when this earthquake comes, it could bring down skyscrapers. It will be similar in power and destructive force as the tremor that spawned the 2004 Indian Ocean tsunami. And it will send a wave much more destructive than last week's from the quake off of Chile rippling across the Pacific Ocean. If you live on or near the coast, you will be in harm's way.
This is not an alarmist message; it's realistic. The science is very clear on this point, and fortunately many officials in charge are paying attention. Schools, hospitals, and other critical infrastructure in the shadow of the Cascadia are being shored up against the coming seismic assault. But the magnitude of the threat requires that everyone, from seismologists on down to the average citizen, needs to be aware of the risks, and how to prepare themselves for an extreme event that is a matter of "when," not "if."
Image: Getty
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