Have we discussed the Cascadia subduction zone yet?

[onewhippedpuppy]

Wow, that was a frightening education. Incredibly well written article. I think I'll keep our tornadoes.

The comparison to Japan is interesting as well. That country is obsessive about their tsunami warning systems and safety plans, yet thousands still died. Having a similar event in a populated region that has no warning and no plan is a frightening proposition.

[Crowbob]

Originally Posted by arcsine

Yawn.

This is old and accepted news. In Washington alone we have three big a$$ volcanoes (OK, two and a half) and the entire Puget Sound is resplendent with fault lines. A lot of Seattle is built on fill (Downtown, Harbor Is, Greenlake) and effecting all this is the subduction zone. Anyone paying attention would be comfortable saying it is going to be catastrophic if something happens.

And just what can be done about it? Empty Downtown and rebuild on bedrock? Build a big dam around the Sound as a seawall to control the tsunami? Raise all the Boeing plants up on stilts? Maybe some causeways to control the flooding from Rainer or Baker blowing up? As mentioned by Scuba Steve, Seattle is not well know for progressive thinking about infrastructural improvements.

So, what should be done to better prepare for an earthquake, eruption or tsunami to protect millions of people over hundreds (thousands?) of miles of coastline?

The best thing would be to figure out a way to make millions of dollars off of it. I'd start with a PR campaign which includes a slick propaganda movie complete with Polar Bears and Hockey sticks.

[Hawkeye's-911T]

PBS recently ran a program on mega-quakes & the Pacific ring of fire - nothing new by way of information but quite sobering with respect to the 'what if' factor.

Cheers
JB

[island911]

Originally Posted by onewhippedpuppy

Wow, that was a frightening education. Incredibly well written article. I think I'll keep our tornadoes.
.

I heard that each year there is a 1 in 300 chance of a big quake hitting the upper left coast - a disaster. While those odds are a bit high, it still seems better than living in a place that has an annual Disaster Season. YMMV

[island911]

Originally Posted by J P Stein

..
During the last "big one" in Alaska, the tidal surge moving up fiords moved up to a height of 1200 feet when it reached the end of the channel. Those channels were small compared to Puget Sound. ...

the fiords actually focus the tidal energy. So, I expect, places like La Conner will be La Goner, but Seattle proper (on a steep grade, and wide open water) will stay mostly in tact (from tsunami water)

[MikeSid]

You cannot prevent or survive such an event. You can only be somewhere else when it happens.
That works fine for people. Early warning systems and evacuation routes are about all you can do.
But if a huge Tsunami hits, who really gives a rip if the power grid is shut off in advance. Sure that might prevent a few fires. But it's not like the water is going to recede and I'm going to plug in my toaster and have a spot of tea.
So the time and expense to protect against the loss of infrastructure from such an event is a fools errand. Get the people out and rebuild. If the big one hits with any kind of force described in that article, no amount of planning is going to save the physical assets of the area. Focus on saving people and the only viable way to do that is to warn them and figure out the fastest way to get them the hell out of there.

[GG Allin]

If it happens in my lifetime, I'll definitely tune in and watch.

[Porsche-O-Phile]

I'm buying land in western Idaho - new oceanfront property!

[Rtrorkt]

Originally Posted by island911

the fiords actually focus the tidal energy. So, I expect, places like La Conner will be La Goner, but Seattle proper (on a steep grade, and wide open water) will stay mostly in tact (from tsunami water)

Did a master plan for Harborview Hospital some time ago. For those of you who have driven the 5 into Seattle it is the pile of bricks in the east side of the interstate on top of the hill just before you reach the first downtown exit. My structural engineer used the code madated ground movement to require horizontal movement of 5 or so feet and a vertical component of 3 feet or so. But he had studied the Cascadia science and basically said no structure in Seattle will survive the actual event. Harborview that is the trauma center for 5 states will end up on the 5 at the bottom of the hill. In his view vertical displacement of 30 to 100 feet can be expected. Frankly speaking the 1906 SF earthquake is a cakewalk in comparison. Even the New Madrid quake that re routed the Mississippi River is no match for the a Cascadia big one

I lived in SF for 10 years so I think I get the fatalism of living on the fault line. I did a project in Bellevue WA where the code officials were/are in denial about the need for seismic safety. Not much you can do if your choice is to live in the Pacific Northwest. Love the landscape and really like Seattle. Not a place I would want to be when this event happens.

Guess now we should move on to the Yellowstone super volcano

[Westy]

I've long been a student of plate tectonics, and believe this one is the next great 'natural' threat to the Continental US. I go riding up there 3 times a year. I always bring lots of extra food, and the first thing I do is fill the MH water tank. Cascadia is no joke. Especially since it's a subduction, which means when it goes there's a better than good chance Ranier will throw a few tissy fits. If you search the net, there's actually a picture of the fault line out in the Pacific, and you can see where it's turning down into the crust. I believe the Jaun de Fuca plate is the small one causing the confusion. Kind of like an island stuck out in the great sea. Lots of reading available on this.

[GH85Carrera]

Originally Posted by island911

I heard that each year there is a 1 in 300 chance of a big quake hitting the upper left coast - a disaster. While those odds are a bit high, it still seems better than living in a place that has an annual Disaster Season. YMMV

300 MPH winds from a F5 hit a VERY small area and really mess that one tiny little area up. The vast majority of the city does not even have a blip on the electricity. Life goes on as normal.

With a 9.0+ earthquake and giant tsunami thousands of SQUARE MILES are devastated with no warning and no way to survive.

We have a tornado shelter. There is no such thing as a earthquake shelter or a tsunami shelter except to get the F**K out of the area. That will be impossible.

[Westy]

FWIW, they've had some 3 + 4 earthquakes up there the last few months. LOTS of small ones is a good thing. NO small ones,,,,bad. I have lived on and near faults my entire life, and been thru several. ^^^^^^^ Point well taken, but I'll stick with earthquakes over them 'nados any day.

[Crowbob]

Yellowstone Caldera, Global Warming, Cascadia Subluxations or whatever you call it, you choose your poison. I'm staying in Michigan. The biggest threat to our survival is Detroit.

[Westy]

Originally Posted by Crowbob

The biggest threat to our survival is Detroit.

You might have the biggest obstacle to overcome!!

[kach22i]

A much shorter but older article.

13-Year Cascadia Study Complete — And Earthquake Risk Looms Large
Chris Goldfinger
August 30, 2012
https://ceoas.oregonstate.edu/features/pnwearthquakerisk/

A comprehensive analysis of the Cascadia Subduction Zone off the Pacific Northwest coast confirms that the region has had numerous earthquakes over the past 10,000 years, and suggests that the southern Oregon coast may be most vulnerable based on recurrence frequency.

Written by researchers at Oregon State University, and published online by the U.S. Geological Survey, the study concludes that there is a 40 percent chance of a major earthquake in the Coos Bay, Ore., region during the next 50 years. And that earthquake could approach the intensity of the Tohoku quake that devastated Japan in March of 2011.

[BE911SC]

Have you noticed that everywhere you look, especially on television and the Internet, that the world is coming to an end very soon?

I remember thinking as an 11-year old kid in 1973 that there wouldn't be any gasoline when I was old enough to drive. Then there would be but the price would be too high. Then gasoline-powered cars would be done away with and we'd be in electric cars or riding bicycles. After almost 45 years of gloom-and-doom about oil supplies we are now in a global oil glut (for various reasons) and the price per barrel is just under 60 bucks today.

So now I'm supposed to get scared about a huge earthquake that no one actually knows when it's coming?

[Rick Lee]

Oil is a supply and demand thing, totally unrelated to apocalyptic disasters. Oil could become far more scarce and still get cheaper due to lack of demand in the future. This Cascadia earthquake is pretty much a guarantee, just a matter of time, not world politics or economics. It could happen tomorrow or in 100 yrs., but it will happen. Seems to me it's even more of a sure thing than Yellowstone blowing up and that's pretty much a guarantee too; just with a much longer period between eruptions.

[island911]

We're going to be hit by a massive meteorite again too. (shrug)

Originally Posted by BE911SC

...
So now I'm supposed to get scared about a huge earthquake that no one actually knows when it's coming?

Well, now that the whole "global Warming" thing fizzled ... we need something to fear.

[island911]

Originally Posted by Rtrorkt

Did a master plan for Harborview Hospital some time ago. For those of you who have driven the 5 into Seattle it is the pile of bricks in the east side of the interstate on top of the hill just before you reach the first downtown exit. My structural engineer used the code madated ground movement to require horizontal movement of 5 or so feet and a vertical component of 3 feet or so. But he had studied the Cascadia science and basically said no structure in Seattle will survive the actual event. Harborview that is the trauma center for 5 states will end up on the 5 at the bottom of the hill. In his view vertical displacement of 30 to 100 feet can be expected. Frankly speaking the 1906 SF earthquake is a cakewalk in comparison. Even the New Madrid quake that re routed the Mississippi River is no match for the a Cascadia big one..

interesting. Thing is, we don't know how the energy of slipping plates will be released. That is, massive energy can be sharp, or spread out. Shifting with a slow large displacements, and/or with small sharp waves. A mag 9.x relates to energy released; and those quakes are often many minutes long. (which spreads the energy over time) The distance away from the center is important too, as the energy falls off quickly. 1/R^2.

So, while it's fun to extrapolate the effects of a small close quake to that of a very large quake off the coast, it often doesn't work the way people would expect. (Hollywood style)

I expect that the damage to Seattle proper is WAY over stated. The coast will be hammered hard, Victoria will not be pretty and Whidbey island will become two islands.

[onewhippedpuppy]

Originally Posted by island911

I heard that each year there is a 1 in 300 chance of a big quake hitting the upper left coast - a disaster. While those odds are a bit high, it still seems better than living in a place that has an annual Disaster Season. YMMV

Tornadoes impact neighborhoods. I will be safe in my basement. When this event occurs the human and economic impact will likely eclipse the sum total of every tornado in the USA.