Few experts thought the seismic zone off Sendai, Japan, was capable of such violence (Nature)

[jpak]

Giant shock rattles ideas about quake behaviour

http://www.nature.com/news/2011/110315/full/471274a.html

"This earthquake is a lesson in humility," says Emile Okal, a geophysicist at Northwestern University in Evanston, Illinois, who studies great earthquakes and tsunamis. Few experts had thought that the seismic zone near Sendai, Japan, was capable of producing earthquakes anywhere near as powerful as the magnitude-9.0 shock on 11 March, the largest on record in Japan. Okal and his colleagues want to understand why the event was so much stronger than many people expected — and what it means for seismic risks in Japan and elsewhere around the globe.

The quake happened along a seam in the planet's surface where the Pacific Ocean floor is diving beneath the tectonic plate carrying northern Japan (see 'Collision zone'). That process of subduction triggers the largest earthquakes in the world, such as the magnitude-9.5 Chilean quake in 1960 and the magnitude-9.1 Sumatran quake in 2004. But geophysicists had thought that great subduction-zone earthquakes happened only where younger oceanic crust scrapes its way into the mantle. Older crust, which is cooler and denser, was thought to slide much more readily downward, triggering smaller quakes. And the ocean crust off the northeast part of Japan, having formed about 140 million years ago, is about as old as it can get.

The history of the Sendai region seemed to support that idea. "There has been seismicity but not really great-earthquake seismicity," says Hiroo Kanamori, a seismologist at the California Institute of Technology in Pasadena. In the past few centuries, the subduction zone off the coast of Sendai has generated earthquakes of up to magnitude 8 or so, but nothing as powerful as a 9, which releases 30 times more energy.

Given that history, seismologists in Japan did not consider great earthquakes to be a threat to the Sendai area. And although that region was one of Japan's best-prepared for tsunamis, the high sea walls along much of the coast were built to stop waves far smaller than the 13–15-metre-tall giants that battered the coastline, causing most of the damage and triggering a nuclear crisis.

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Beware the happy talk about the seismic vulnerability of California's San Onefre and Diablo Canyon nuclear plants...

yup

[DCKit]

1. Those experts should have asked the average folk on the streets of Chile, Peru...

and Alaska if such a thing were possible.

The entire world is getting burned out on "Who could have foreseen this?"

[FBaggins]

2. Why?

The article implies that it's ten times as strong as anything in their history.

[Old and In the Way]

6. No doubt that's true.

But that said, can we also agree that if 9.0 quakes are real, couldn't a 10 or 11 also be within the province of some future reality? And if there is a future possibility that they could occur, can we honestly allow the continued use of fusion reactor based power systems?

[FBaggins]

8. Yes... that's theoretically possible. But think about what your conclusion means.

I can give you a whole list of things that WILL someday happen... we just don't know when.

Are they a reason to not build anything that could be impacted by such an event?

* "The big one" earthquake in southern CA.

* Super Volcano under Yosemite that ends 90% of life as we know it in the U.S.

* Super Tsunami that takes out most of the East Coast of the U.S. for miles inland.

* Asteroid impact.

* Republicans retake the White House and filibuster-proof Senate majorities.

* Earthquake or meteorite takes out a major dam.

Do we really believe that if there is "a future possibility that they could occur" we can't continue to use hydro power or live along the coast, or live anywhere in the U.S.?

Heck... with that standard, do you even drive a car or ride a train or plane? Live in a home with a second floor?

[Old and In the Way]

9. There's no planning for natural disasters, that's a given.

But building nuclear power plants and voting in Republicans are well within our control. To be done in by Mother Nature is one thing, to be done in by our hand is another...and, yes, I know I can die by the man made products, but a car accident won't impact 100's of thousands or millions of people on the other side of the planet.

[FBaggins]

10. Sorry... that's not what I meant.

we should plan for natural disasters. And we do.

We should just recognize that there are also disasters that will overcome those plans.

But building nuclear power plants <is> well within our control.

Yes... as are building bridges and tall buildings and hundreds upon hundreds of other things. The key is to get the risk down to the point where it does not add appreciably to the general risk of being alive.

Note that over 10,000 people appear to have perished (perhaps twice that number) in Japan in the last week and not a single one died because of radiation from a reactor. Why are we focusing on global policy changes (at massive expense) to adjust one piece that doesn't compare to the total?

but a car accident won't impact 100's of thousands or millions of people on the other side of the planet.

And neither has this.

Think about it. One of the oldest reactors (and three not much newer). An old containment design. An unprecedented earthquake/tsunami/power outage and there still isn't a disaster that's going to be so devestating (assuming it doesn't get MUCH worse)?

Then you look at the plants they're developing now and see that the biggest problems (loss of pumps and power) is already something they can deal with.

Why not just say "don't place them by the ocean along a fault line, and build only the newer safer designs." ?

[Old and In the Way]

11. OK, you win.

let's build more nuclear fusion power plants.

[FBaggins]

12. Hey... if we can get to FUSION... that would be great.

No more waste problem, etc. :)

[Old and In the Way]

14. Whoopsie...meant fission.

We'll probably get fusion technology about the time we get clean coal.

[Wilms]

3. Thanks DC.

You spared me the embarrassment of doing a lousy job of try to say what you so well conveyed.

The entire world is getting burned out on "Who could have foreseen this?"

:toast:

[DCKit]

4. Thanks for the compliment.

There are many DU posters I greatly admire for being able to cut through the B.S. and provide a concise rebuttal to a long-winded, obfuscating argument. They are an example to us all.

[Wilms]

5. Zappa was like that, too.

http://www.youtube.com/watch?v=vKITpVovTAE

[DCKit]

7. George Carlin is a personal hero. nt

[CRH]

13. Experts, only the uninformed think scientists are experts, ...

A couple of examples, look at the mess up at Hanford, who could have known?

Think of the widespread use of PCB's, who could have known?

Think of the category 5 hurricane in New Orleans. How long was the electricity out after the insufficient levies broke? Who could have known? Damn lucky there wasn't a nuclear power plant near.

Where are nuclear power plants located in the US? Real close to fresh water supplies? With our rapidly changing climate, and the increasing severity of storms, who knows where the 500 and 1000 year flood planes might be. How long will the power be out, and how high are the emergency generators? How many existing power plants are waiting to test that five hundred year level, recorded by the indigenous indians of course. Just waiting for another, who could have known?

Believing in experts to meet the ultimate limits of nature, and engineer to perfection the first time, is arrogance. How many planes fly without problems the first time, how many cars are later recalled, didn't a dome collapse this winter in Minneapolis? Remember the space shuttle, twice, designed by experts.

Experts designed the Mark I containment, and within a decade it was thought to be unsafe, the design flawed. And because of the price, and profit, it was never replaced with newer technology. Instead it was left to test the laws of probability. It failed, along with the experts of the day, and the experts of the present, who allowed the continued function.

Experts, huh?