The next great American earthquake may not occur where you would expect

[RandySF]

The biggest earthquakes in the country are not in California. A much greater hazard, at least in terms of sheer magnitude, exists to the north of the San Andreas Fault where the ocean crust is being forced beneath the North American continent.

Known as the Cascadia Subduction Zone, this 680-mile long stretch of colliding land mass 50 miles offshore of Oregon, Washington state and southern British Columbia is capable of generating magnitude 9 earthquakes 30 times more powerful than the worst the San Andreas can dish out.

"There are lots of other earthquakes that may happen first, but they won’t be as big," said marine geologist Chris Goldfinger of Oregon State University in Corvallis.

An earthquake of this size would completely devastate the region, which includes Portland, Seattle and Vancouver. There could be thousands of deaths and unprecedented damage for a quake in this country. Major travel routes will be impassable. The shaking could last a full four minutes, which would damage or bring down structures that could have survived a shorter duration.

On top of the danger from shaking, within minutes, a tsunami would likely inundate the low-lying coastal areas. Cascadia is the same type of fault that caused the 2004 Sumatra quake and tsunami.

Fortunately, these mega quakes only come around once every few hundred years. Unfortunately, the fault may be due for another big one any day now.

The last monster quake that ruptured the entire length of the Cascadia fault occurred in 1700 and was around a magnitude 9. It created a tsunami that crossed the entire Pacific Ocean and caused damage along parts of the Japanese coast.

Scientists had calculated an average time between these major quakes of around 530 years. But Goldfinger’s recent research on marine landslides caused by earthquakes over the last 12,000 years has revealed many magnitude 8 earthquakes on the southern portion of the fault in the intervening years, bringing the average down to 270 years.


http://www.wired.com/wiredscience/2008/10/five-us-earthqu/

[Confusious]

1. A 9, only a 9?

Anchorage Alaska had a 9.2 in '64. Alaska holds two of the top 5 spots for this century.

Of course, there aren't as many people there, and after the '64 earthquake we learned not to build on shit that would slide in the bay.

[gateley]

2. Alaska has a lot more wilderness than we do in Seattle, less

populated. So I'd be happy with "only" an 9. :7

[Rex]

3. Goldfinger?

Sounds like a super villain!

[WHEN CRABS ROAR]

4. I'm 50 miles from the Cascadia Subduction Zone and yes,

it is overdue. Also Yellowstone is another possibility of a very large event.

[YellowRubberDuckie]

5. We have been having quakes here in the OK City area....

It's been ramping up. I think the biggest we've had was a 5 or something. They're saying the next big one will probably be a fault near the Mississippi River, I want to say it's in Missouri, from what I've heard recently.
We're talking about having a survival skills weekend at my house here in the next few weeks to help out friends be prepared in case something huge happens like Japan. I have some friends who couldn't last a day without electricity. This is always in the back of my mind.
I'm terrified....

[electricD]

10. the new madrid fault line

this is the same fault line that caused the mississippi river to run backwards for 3 days back in the 1800's. can't remember exact year.

[KillCapitalism]

16. Yep, it was 1811-1812

More info here:

http://earthquake.usgs.gov/earthquakes/states/events/1811-1812.php

There wasn't much mayhem in St. Louis then b/c it was a quaint village of 1,500 people at the time.

[xmas74]

18. But nowadays it could

destroy St Louis and Memphis.

I've been to New Madrid. When you realize what happened there it's awe-inspiring and frightening at the same time. If it rang church bells in Boston what will it do to my home near Kansas City?

[xmas74]

17. Winter of 1811-1812.

It was a series of earthquakes. I believe there were four in a few months, along with what was considered almost nonstop aftershocks. Accounts from the time period include people thinking that the gates of hell were opening beneath them and releasing their dead, and people asking why God had forsaken them. It had to be a nightmare.

Research shows that if we have a seven plus it could destroy most of St. Louis and Memphis.

[Boswell]

19. heard stories about it ringing bells in Boston...

centered in missoui if I recall correctly

[Rabblevox]

11. don't be terrified, be prepared...

and it sounds like you're taking the right steps.

[YellowRubberDuckie]

12. We have a ton of camping equipment. It will take sometime to round it up...

...but we know where it all is. We'll be OK. And we have a ton of rice and nonperishables that will get us through.

[RandySF]

15. You've much more to worry about from tornadoes.

[underseasurveyor]

6. They say the Cascadian subduction zone

Is just like Sumatra. And we know how that went:scared:

[Rosa Luxemburg]

7. I worry also about Mt Ranier

isn't it a volcano?

[Rabblevox]

8. Portland, OR chiming in. yuppers...

the Cascadia Subduction Zone is overdue to shift. Next year? Hundred years? Who knows? What would a 30-foot wave rushing up the Colombia gorge do? (and let's not forget about Hanford and their loverly box o'toxins)

I do think that Seattle and Vancouver will probably get hit harder than Portland, just because of geography.

I've got multiple routes to high ground memorized, and a "bug-out" bag packed.

[B Calm]

9. I think the big one will be in the midwest, NEW MADRID FAULT

It could be so powerful it could drain the Great Lakes into the Gulf of Mexico.

[Rabblevox]

13. Yup, New Madrid is also a leading contender for the "next big one", and "frakking" ain't helping./nt

[xmas74]

20. That's the one I'm afraid of.

I'll feel that one.

[dogday]

14. Arkansas has been having small quakes along with Oklahoma

the Madrid Fault line is the one I think we should be concerned with.