Jul 14, 2015 by



A comparison of the history of powerful earthquakes along fault off the coast of northern California, Oregon, and Washington, with events from human history. <a href="http://graphics8.nytimes.com/images/2013/06/17/blogs/dotcascadia/dotcascadia-master1050.jpg">Large version</a>. <a href="http://www.oregongeology.org/sub/quarpub/CascadiaWinter2010.pdf">More background</a>.
A comparison of the history of powerful earthquakes along fault off the coast of northern California, Oregon, and Washington, with events from human history. Large versionMore background.Credit Oregon Department of Geology and Mineral Industries

Updated, 7:56 p.m. | If you live in the Pacific Northwest or have friends or family there, I encourage you to read and share Kathryn Schulz’s chilling New Yorker feature digging in on the inevitable seismic disaster building day by day in the region.

Strain is growing along the Cascadia fault beneath the seabed offshore and, as seismologist Chris Goldfinger told Schulz, “[T[he gap between what we know and what we should do about it is getting bigger and bigger.”

Frequent readers of Dot Earth will know that this particular earthquake threat, especially the danger it poses to hundreds of unreinforced schools, has been a longtime focus of mine. My posts probably add up to far more text than even this New Yorker feature. But the visceral power in long-form storytelling might have more potential to stir a response (one can at least hope). Here’s Schulz’s gut-punch paragraph:


The <a href="http://earthquake.usgs.gov/learn/glossary/?term=subduction">Cascadia fault off the Northwest Coast</a> has generated a sequence of great earthquakes over millenniums. <a href="http://oregonstate.edu/ua/ncs/archives/2012/jul/13-year-cascadia-study-complete-%E2%80%93-and-earthquake-risk-looms-large">Another is due</a>, seismologists say.
The Cascadia fault off the Northwest Coast has generated a sequence of great earthquakes over millenniums. Another is due, seismologists say.Credit USGS.gov

When the next very big earthquake hits, the northwest edge of the continent, from California to Canada and the continental shelf to the Cascades, will drop by as much as six feet and rebound thirty to a hundred feet to the west—losing, within minutes, all the elevation and compression it has gained over centuries. Some of that shift will take place beneath the ocean, displacing a colossal quantity of seawater. (Watch what your fingertips do when you flatten your hand.) The water will surge upward into a huge hill, then promptly collapse. One side will rush west, toward Japan. The other side will rush east, in a seven-hundred-mile liquid wall that will reach the Northwest coast, on average, fifteen minutes after the earthquake begins. By the time the shaking has ceased and the tsunami has receded, the region will be unrecognizable. Kenneth Murphy, who directs FEMA’s Region X, the division responsible for Oregon, Washington, Idaho, and Alaska, says, “Our operating assumption is that everything west of Interstate 5 will be toast.”

Here’s the second punch in the one-two sequence:

In the Pacific Northwest, everything west of Interstate 5 covers some hundred and forty thousand square miles, including Seattle, Tacoma, Portland, Eugene, Salem (the capital city of Oregon), Olympia (the capital of Washington), and some seven million people. When the next full-margin rupture happens, that region will suffer the worst natural disaster in the history of North America. Roughly three thousand people died in San Francisco’s 1906 earthquake. Almost two thousand died in Hurricane Katrina. Almost three hundred died in Hurricane Sandy. FEMA projects that nearly thirteen thousand people will die in the Cascadia earthquake and tsunami. Another twenty-seven thousand will be injured, and the agency expects that it will need to provide shelter for a million displaced people, and food and water for another two and a half million. “This is one time that I’m hoping all the science is wrong, and it won’t happen for another thousand years,” Murphy says.

I hope you’ll read the whole article, then sift for more information (Oregon, the state of Washington, California, British Columbia) and — if you live in the region — act on it.

Postscript, 8:00 p.m. | In Oregon, there are fresh signs that people are acting. This note (some email shorthand is adjusted) came in from Ted Wolf, a longtime campaigner for school retrofits:

It’s been a banner year for seismic resilience policy in Oregon — and dollars for retrofits for Oregon schools — $175 million in new investment for school retrofits in the next two years — a 12x increase over the largest authorization we have ever managed before! And an additional $125 million in matching grants for school districts that pass local school bonds. It’s possible the supply of funds will exceed the demand!

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