Motus Mentis

Nine years ago, in a post about the Eyjafjallajokul volcano in Iceland, I wrote the following thing:

Meanwhile, if you’re starting up an End Of Days seismic-catastrophe pool at the office, I think the smart money is on the Cascadia Subduction Zone up in the Pacific Northwest.

Admittedly, that was nine years ago, and nothing’s happened so far. But nine years, in geological terms, is the heartbeat of a gnat. Today I ran across an item at City Journal describing the CSZ threat in minatory detail:

When it happens, the earth will slip by roughly 60 feet along a rupture zone more than 600 miles long, unzipping the sea floor at roughly two miles per second and convulsing the West Coast for as long as five minutes. Bridges will fall. Wet soil will liquefy. Brick and masonry buildings will shatter. Skyscrapers built before modern earthquake codes may topple. City centers in Portland, Seattle, and Vancouver will be buried beneath glass shards and rubble. Everything underground””water mains, natural gas pipes””will be crushed. Land that has bulged upward from tectonic pressure for the past 300 or so years will collapse to baseline, permanently altering the topography and plunging low-lying coastal areas into the ocean. The inland Cascade Mountains will knock the knees out from under the earthquake, but numerous landslides will occur, especially on roads built with a “cut and fill’ method, where flat slabs get cut out of rock walls and smoothed over with soft fill. Just a few minutes after the quake finally stops, the second hammer blow will strike. Tsunami waves up to 50 feet high will rip the face of the coastal region clean off the map, pulverizing everything and killing everyone in their path.

It’s hard to say in advance how many will die. It depends on the time of year and the time of day. The Pacific Northwest as far north as British Columbia has a Mediterranean precipitation pattern, with warm, dry summers and cool, wet winters. An earthquake during the rainy season will result in a lot more liquefaction and landslides. Better for disaster to strike during the summer, then””except that thousands more tourists will be at the beach and get swept away by tsunamis. The ideal time would therefore be after Labor Day, when the beach is less crowded but before the autumn rains come, and better by far at 4 AM, when schools and downtown high-rises are empty and there’s little or no traffic on bridges. “Best case,’ says geologic-hazard coordinator Althea Rizzo at the Oregon Office of Emergency Management, “is between 2,000 and 6,000 fatalities.’ If the quake happens during the school year, she adds, fatalities could tally in the tens of thousands. “That’s just for Oregon. And that’s not factoring in the tsunami, which will kill even more people.’ The United States could conceivably lose more people in an hour, in a single part of the country, than we lost over an entire decade in the Vietnam War.

The Northwest coast being a “deep-blue” area, no doubt the primary concern will be the catastrophe’s disparate impact on women, minorities, undocumented immigrants, and endangered species. But it looks as if there will be plenty left to go around.

Read the article here.