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Baobab

(4,667 posts)
Sun May 8, 2016, 01:56 AM May 2016

Huge 9.0+ Earthquake/Tsunami in Cascadia Region Could Devastate Pacific Northwest

http://www.newyorker.com/magazine/2015/07/20/the-really-big-one--?intcid=mod-most-popular


"Certain disasters stem from many small problems conspiring to cause one very large problem. For want of a nail, the war was lost; for fifteen independently insignificant errors, the jetliner was lost. Subduction-zone earthquakes operate on the opposite principle: one enormous problem causes many other enormous problems. The shaking from the Cascadia quake will set off landslides throughout the region—up to thirty thousand of them in Seattle alone, the city’s emergency-management office estimates. It will also induce a process called liquefaction, whereby seemingly solid ground starts behaving like a liquid, to the detriment of anything on top of it. Fifteen per cent of Seattle is built on liquefiable land, including seventeen day-care centers and the homes of some thirty-four thousand five hundred people. So is Oregon’s critical energy-infrastructure hub, a six-mile stretch of Portland through which flows ninety per cent of the state’s liquid fuel and which houses everything from electrical substations to natural-gas terminals. Together, the sloshing, sliding, and shaking will trigger fires, flooding, pipe failures, dam breaches, and hazardous-material spills. Any one of these second-order disasters could swamp the original earthquake in terms of cost, damage, or casualties—and one of them definitely will. Four to six minutes after the dogs start barking, the shaking will subside. For another few minutes, the region, upended, will continue to fall apart on its own. Then the wave will arrive, and the real destruction will begin.

Among natural disasters, tsunamis may be the closest to being completely unsurvivable. The only likely way to outlive one is not to be there when it happens: to steer clear of the vulnerable area in the first place, or get yourself to high ground as fast as possible. For the seventy-one thousand people who live in Cascadia’s inundation zone, that will mean evacuating in the narrow window after one disaster ends and before another begins. They will be notified to do so only by the earthquake itself—“a vibrate-alert system,” Kevin Cupples, the city planner for the town of Seaside, Oregon, jokes—and they are urged to leave on foot, since the earthquake will render roads impassable. Depending on location, they will have between ten and thirty minutes to get out. That time line does not allow for finding a flashlight, tending to an earthquake injury, hesitating amid the ruins of a home, searching for loved ones, or being a Good Samaritan. “When that tsunami is coming, you run,” Jay Wilson, the chair of the Oregon Seismic Safety Policy Advisory Commission (OSSPAC), says. “You protect yourself, you don’t turn around, you don’t go back to save anybody. You run for your life.”

The time to save people from a tsunami is before it happens, but the region has not yet taken serious steps toward doing so. Hotels and businesses are not required to post evacuation routes or to provide employees with evacuation training. In Oregon, it has been illegal since 1995 to build hospitals, schools, firehouses, and police stations in the inundation zone, but those which are already in it can stay, and any other new construction is permissible: energy facilities, hotels, retirement homes. In those cases, builders are required only to consult with DOGAMI about evacuation plans. “So you come in and sit down,” Ian Madin says. “And I say, ‘That’s a stupid idea.’ And you say, ‘Thanks. Now we’ve consulted.’ ”

These lax safety policies guarantee that many people inside the inundation zone will not get out. Twenty-two per cent of Oregon’s coastal population is sixty-five or older. Twenty-nine per cent of the state’s population is disabled, and that figure rises in many coastal counties. “We can’t save them,” Kevin Cupples says. “I’m not going to sugarcoat it and say, ‘Oh, yeah, we’ll go around and check on the elderly.’ No. We won’t.” Nor will anyone save the tourists. Washington State Park properties within the inundation zone see an average of seventeen thousand and twenty-nine guests a day. Madin estimates that up to a hundred and fifty thousand people visit Oregon’s beaches on summer weekends. “Most of them won’t have a clue as to how to evacuate,” he says. “And the beaches are the hardest place to evacuate from.”

Those who cannot get out of the inundation zone under their own power will quickly be overtaken by a greater one. A grown man is knocked over by ankle-deep water moving at 6.7 miles an hour. The tsunami will be moving more than twice that fast when it arrives. Its height will vary with the contours of the coast, from twenty feet to more than a hundred feet. It will not look like a Hokusai-style wave, rising up from the surface of the sea and breaking from above. It will look like the whole ocean, elevated, overtaking land. Nor will it be made only of water—not once it reaches the shore. It will be a five-story deluge of pickup trucks and doorframes and cinder blocks and fishing boats and utility poles and everything else that once constituted the coastal towns of the Pacific Northwest.


To see the full scale of the devastation when that tsunami recedes, you would need to be in the international space station. The inundation zone will be scoured of structures from California to Canada. The earthquake will have wrought its worst havoc west of the Cascades but caused damage as far away as Sacramento, California—as distant from the worst-hit areas as Fort Wayne, Indiana, is from New York. FEMA expects to coördinate search-and-rescue operations across a hundred thousand square miles and in the waters off four hundred and fifty-three miles of coastline. As for casualties: the figures I cited earlier—twenty-seven thousand injured, almost thirteen thousand dead—are based on the agency’s official planning scenario, which has the earthquake striking at 9:41 A.M. on February 6th. If, instead, it strikes in the summer, when the beaches are full, those numbers could be off by a horrifying margin."

http://www.newyorker.com/magazine/2015/07/20/the-really-big-one--?intcid=mod-most-popular
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clayton72

(135 posts)
4. Professor Nick Zentner's recent lecture The Really Big One: Overdue? Toast? Really?
Sun May 8, 2016, 04:58 AM
May 2016


If you're interested in this subject, please check out this video from a geology professor, Nick Zentner.

For more on Nick:
http://www.geology.cwu.edu/facstaff/nick/zentner.html

More Geology videos by Nick:
https://www.youtube.com/user/GeologyNick

pnwmom

(108,925 posts)
6. This other article has a different slant. It won't be fun, but the NW probably won't be "toast."
Sun May 8, 2016, 05:09 AM
May 2016

And the worst problems would be on the coast, where the population density is much lower, not in Seattle or Portland.

http://www.slate.com/articles/health_and_science/science/2015/07/kathryn_schulz_s_new_yorker_story_on_pacific_northwest_earthquake_geologists.html

Baobab

(4,667 posts)
7. Have you ever been in a large earthquake or similar?
Sun May 8, 2016, 11:12 AM
May 2016

Its very unpredictable what happens. Ive been lucky the two times I have been. Lived in very sturdy old wooden buildings. But others were not so lucky.

Lots of people living in parks for awhile. Camping out.

People do get killed in them. I had one friend who literally almost drove off a bridge into thin air.

Since we're on the PNW, I had another friend, Jeremy, who survived the Mt St Helen's eruption. He was literally right there.

It was like a nuke, he was that close to it.

I wonder where he is now. He was a juggler at the time, a very good one. The people he was camping out with were killed. They were at Spirit Lake.

he best advide for those areas is probably study geology and make sure you are living on solid ground tha isnt in any potential flood or liquefaction zones. Also not on a steep slope. Being on a small hill is likely best, I think, assuming its not a dormant volcano

pnwmom

(108,925 posts)
8. Seattle had a 6.8 some time ago (ten or 15 years?). We get one of those every 40 or 50 years.
Sun May 8, 2016, 01:23 PM
May 2016

It was interesting. First there was a loud clanging noise, so I thought our metal boiler was about to blow up. So I ran outside. That's when I noticed the ground was rolling underneath me -- like an ocean wave. Very weird.

After it finally stopped I walked over to the elementary school because one of my children was there, and everything there was fine, too.

Trailrider1951

(3,409 posts)
9. I would highly recommend Jerry Thompson's book for those interested in the geology of
Wed May 11, 2016, 12:04 PM
May 2016

the Pacific Northwest:

https://www.amazon.com/Cascadias-Fault-Earthquake-Tsunami-Devastate-ebook/dp/B008BQDX4A?ie=UTF8&keywords=jerry%20thompson&qid=1462981262&ref_=sr_1_3&s=books&sr=1-3

Mr. Thompson is a film and print journalist, not a geologist. However, I found the book to be a highly accurate portrayal of the development of understanding the complex geology of the region, and how the Pacific Northwest fits into the "Ring of Fire" scenario that explains the geomorphology of the Pacific basin. This book reads like a detective novel, and is not the sensationalistic scare-monger book you would think it was from the cover. Plenty of history and scientific facts, but presented in terms the layman can deal with.

The Pacific Northwest, from British Columbia to northern-most California is in what geologists call a subduction zone setting, characterized by frequent earthquakes (some of them > magnitude 7.0), volcanism of a particular composition and character (the Cascades), and occasional tsunamis. This is similar to the east coast of Japan, the Aleutian Islands off the southern coast of Alaska, and the west coast of South America (Chile, Ecuador and Peru).

Disclaimer: I have children and grandchildren living in the Seattle area, and plan to move there myself later this year. Also, I'm a retired geologist.

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