Saturday, March 12, 2011

Scientists already making discoveries in wake of Japan's temblor

By Eryn Brown

Here's what experts have learned about the earthquake thus far.

Q: What caused it?

A: The earthquake occurred because a portion of the Pacific Plate is being pushed into and underneath the North American plate, forming a so-called subduction zone that built up so much pressure it ruptured, slipping as much as 60 feet.

"This was a planetary monster," said Thomas Jordan, director of the Southern California Earthquake Center at USC.

The earthquake occurred along a patch of an undersea fault that's about 220 miles long and 60 miles wide. Because the fault broke at a shallow depth, it shifted the sea floor, triggering tsunamis throughout the Pacific Ocean.

Q: Was it a surprise?

A: Yes and no. Seismologists said the quake was larger than they thought was possible in that part of the world. "We thought about the Big One as an 8.5 or so," said Susan Hough, a seismologist at the U.S. Geological Survey in Pasadena, Calif. Such an earthquake would have been about one-third as strong as an 8.9 quake.

"But it's not like an 8.9 hit Kansas," she added. "We know Japan is an active subduction zone."

What tripped scientists up was a lack of recent activity in the area, Jordan said. The last earthquake of this magnitude along this plate boundary occurred in the year 869. Seismologists had been debating the fault's potential to break, but they had little data to go on.

"The question was whether that section had locked - accumulating strain - or was it slipping slowly," Jordan said. "We now know that this is a plate boundary that was locked."

Q: You mean there were no hints at all?

A: Brian Atwater, a USGS seismologist based in Seattle, said that Japanese GPS data collected since the 1990s showed that the coast of Japan was being pulled inland at a rate of about 25 feet per century, another indication that the plates were stuck and energy was building between them.



  1. I also heard on the news that they had smaller quakes in the days before the major one. Perhaps that caused them to drop their guard for a moment, thinking it was the quake, rather than what they called a 'pre-shock'.

    Good stuff.

  2. I think it's important not to try to second-guess what could've been done. As technologically advanced as we are, there really is no realistic way to predict earthquakes. I think the Japanese response has been exemplary, and should be taken as an example for the rest of the world.

  3. It's interestng to know more about it

  4. this is no joke. california is in risk...

  5. Mother nature sometimes cannot be predicted, all our technology comes to nothing against our own planet.

  6. Monday, 1 March 2010
    they knew it was coming

  7. interesting stuff

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  8. wow, that's crazy. It's so sad, hopefully people see this and start to take caution.

  9. damn, im sure they did all they could to prepare

  10. The GPS info should have given them more of a heads up. But I'm not scientist.

  11. You just can't rule out the complete random destructive power of nature....scary stuff

  12. It's amazing that even this "much" is known about this stuff. It's not like you can go down there and hold a finger onto it to feel whether it's got a little fever. Damn science, u scary.