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Tremors Predict California Earthquakes 24

Posted by michael
from the drop-off-into-the-ocean dept.
johkir writes "A seismologist at the University of California Berkeley Seismological Laboratory has discovered mysterious tremors deep under the San Andreas Fault that may help predict future earthquakes. The episodes of tremors, which he calls chatter, last from four to twenty minutes and are being recorded from as deep as 40 kilometers beneath the surface -- up to four times the depth of normal earthquakes! These tremors also seem to occur a few weeks prior to detectable surface tremors. Article is published in Science Magazine, but you'll need a subscription, and it is covered in the San Francisco Chronicle and a UC Berkeley press release."
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Tremors Predict California Earthquakes

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  • UC Davis (Score:5, Interesting)

    by eikonoklastes (530797) on Friday December 10, 2004 @01:54PM (#11053886) Journal
    Researchers at UC Davis have also recently made headlines trying to forecast earthquakes (Press release [ucdavis.edu]). I wonder if we're on the brink of a new understanding of earth's geophysical processes.
  • Lessee, tectonic plates sliding over one another in a subduction zone... ...yeah, that would make a noise, I think.
  • "We see this kind of tremor activity inside volcanoes like Mount St. Helens," Nadeau said, "but that's due to the movement of rising magma, and in the tremors we've recorded there's no evidence of volcanism and no seismic waves typical of ordinary earthquakes."

    http://imdb.com/title/tt0120461/ [imdb.com]

  • by flok (24996) *
    Tremors? [imdb.com]
  • Not have earthquake warnings? If you build your state on a major fault line, you deserve what you get. Sure its all warm and everything, but you can get that in Florida, only thet have hurricanes instead.

    Moral of the story: Move from California to Toronto, no hurricanes/tornados/earthquakes. Just remember to buy a jacket before you leave home.
  • by GISGEOLOGYGEEK (708023) on Saturday December 11, 2004 @06:03AM (#11059256)
    This type of deep unusual tremor has been known of for several years.

    Roughly every 14 months, such tremors occur deep under Vancouver Island. Over a 2 week period, the tremors shift southward towards washington state.

    The tremors are related to the subduction of the pacific ocean under north america.

    The san andreas fault is a remnant of the subduction zone, where the pacific spreading ridge has already been consumed. This ridge is still a couple hundred km offshore of vancouver island.

    The deep tremors on the san andreas are probably caused by the change in strain on the system after the same tremors have occured up here. Yes, the deep tremor cycle did occur like clockwork, as predicted by the canadian pacific geoscience center a few months ago under vancouver island. Several 14 month cycles have been observed.

    The weird thing about the tremors is that it represents a rebound in the subduction of the ocean plate. instead of subducting a few cm per year, in two weeks the subduction reverses by about 5cm, and then goes back to the normal.

    It is thought that the changes in strain caused by all this may increase the short term chances of the next big quake hitting southwest BC by a large factor.

    Anywho, go away, there's nothing truly new to see here, it may not have been observed so far south before, but it is not a discovery of a new type of geologic activity, the Canadians already documented it, which maybe the media would have realized had they bothered to look outside your borders for something other than the injustices of Iraq.
    • Canadians don't read the articles either.

      It states quite clearly in the Berkley press release:

      ...are similar to those discovered in the past two years at subduction zones in Japan and the Pacific Northwest.
      Now why, you might ask, are they making a big deal out of this? It's because it's not happening on a subduction zone, but instead under a transform fault.
      • how about you read closer yourself.

        The san andreas is a remnant of the subduction of the pacific spreading ridge.

        It didn't occur to you that there could still be a piece of the ocean plate descending at depth did it huh?
        • that Canadians don't read articles even after being called on it.

          The san andreas is a remnant of the subduction of the pacific spreading ridge.

          Okay, let's go to Plate Tectonics [uoregon.edu] and Volcanoes and the San Andreas Fault [uoregon.edu] for a quick lesson on the differences between subduction zones and transform faults.

          It didn't occur to you that there could still be a piece of the ocean plate descending at depth did it huh?

          Actually, it did occur to me. However, the article states this isn't at a subduction zone (45

    • Well, I know Canada is a BLUE state.

      Is it time to invade Canada again?
    • While yes similar tremors were reported in Canada, to my knowledge this is the first time that we've ever seen them on the San Andreas.

      I grew up in the Bay Area and was there for the 89 quake. With the San Andreas, everytime scientists find something that correlates with detectable earthquakes, it doesn't pan out.

      So the fact that the tremors were reported in Canada AND now they are being seen in San Andreas AND correlating to detectable earthquakes is very promising.

      What most people, even people in the B
  • by dj245 (732906)
    Tremors Predict California Earthquakes

    A bad Tv series on the Scifi channel somehow predicts a major geological event?

Promising costs nothing, it's the delivering that kills you.

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