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Tremors Detected on San Andreas Fault

By ALICIA CHANG
,
AP
posted: 11 HOURS 11 MINUTES AGO
comments: 656
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LOS ANGELES (July 9) - Scientists have detected a spike in underground rumblings on a section of California's San Andreas Fault that produced a magnitude-7.8 earthquake in 1857.
What these mysterious vibrations say about future earthquakes is far from certain. But some think the deep tremors suggest underground stress may be building up faster than expected and may indicate an increased risk of a major temblor.
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San Andreas Fault
U.S. Geological Survey

A seismologist at the University of California, Berkeley, first discovered tremors deep in the San Andreas Fault in 2005.

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Researchers at the University of California, Berkeley, monitored seismic activity on the fault's central section between July 2001 and February 2009 and recorded more than 2,000 tremors. The tremors lasted mere minutes to nearly half an hour.
Unlike earthquakes, tremors occur deeper below the surface and the shaking lasts longer.
During the study period, two strong earthquakes hit — a magnitude-6.5 in 2003 and a magnitude-6.0 a year later. Scientists noticed the frequency of the tremors doubled after the 2003 quake and jumped six-fold after 2004.
Tremor episodes persist today. Though the frequency of tremors have declined since 2004, scientists are still concerned because they are still at a level that is twice as high as before the 2003 quake.
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The team also recorded unusually strong rumblings days before the 2004 temblor.
Results of the research appear in Friday's issue of the journal Science. The work was funded by the U.S. Geological Survey and National Science Foundation.
"The fact that the tremors haven't gone down means the time to the next earthquake may come sooner," said Berkeley seismologist and lead researcher Robert Nadeau.
Nadeau first discovered tremors deep in the San Andreas Fault in 2005. Before that, the phenomenon was thought only to occur in Earth's subduction zones, where one tectonic plate dives beneath another.
USGS seismologist Susan Hough found the latest observations intriguing, but said it's too soon to know what they mean.
"We don't have enough data to know what the fault is doing in the long term," said Hough, who had no part in the research.
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Copyright 2009 The Associated Press. The information contained in the AP news report may not be published, broadcast, rewritten or otherwise distributed without the prior written authority of The Associated Press. Active hyperlinks have been inserted by AOL.
2009-07-09 14:07:02
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Boriken Warrior

09:56 AMJul 12 2009

You mean that Obama can't simply wave his hand and stop it all? Oh, my!

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HunterofthePack

09:55 AMJul 12 2009

The ONLY good thing about living in Massachusetts is that we don't get earthquakes. That's the only good thing.

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ArtistVicki

09:55 AMJul 12 2009

I think this threat of major earthquake is scary. Both of my kids live in Los Angeles. One day while on the phone with my son, he said, "Just a minute Mom...." A few moments passed before he got back on. He said, "Sorry...there were tremors." I don't have to live in California to know these aren't something to laugh about. Here in Michigan we have tornadoes and I know first hand how scary those can be. I think we should pray for those who live in California...for their safety, for their homes, their businesses...Vicki

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bearclaw2304

09:52 AMJul 12 2009

wttrppr I have one better for you. How about we move all of congress to right on top of the fault line. Then we can pray that when it lets loose it opens up a huge crevasse that swallows them up and sends them to see some fiery brimstone. Maybe then we could keep America from following them straight to hell.

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Luweegee3

09:51 AMJul 12 2009

Who cares? The world has we have known it will be colliding with nuclear atoms and nuetrons in the year 2012.Does anyone know exactly what that means?All life forms on the planet earth will cease to exist.There will be a new beginning like it was 10's of thousands of years ago.Planet earth has been here before.This planet just keeps recycling itsself.In 20000 years from now the people of earth are going to say"hey there must have been life on planet earth thousands of years ago"then when the atoms&nuetrons smash again the planet recycles again,over&over&over again.If all life ceases to exist,then all manmade material will vanish like it never was here before,so "WHO CARES"

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BOOGITYSHU

09:50 AMJul 12 2009

Ahhh yes - it s embarrassing enough that some 'Conservative Repuke' has chimed in ( more so w/ a name Cuyahoga - meaning he s from my own area - prone NOT to have Earthquakes, So naturally, it s no skin off his nose )... Where the GOP type attitude is ordinarily to simply Wait - til some catastrophe happens - corral the hapless survivors into a nearby stadium... and wait for a quasi-Darwinian attrition ( Survival of the Wealthiest )... Much as they dislike Darwin - they sure utilize his theories in economic practice.What the Hell s Wrong with being PREPARED- you Idiot. It s the stuff that generates Insurance Companies - You Repukes have no problem there - until something 'Happens' - then the real Tragedy is paying off what you promised.

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SMUchick

09:49 AMJul 12 2009

I thought that the San Andreas Fault produced the 7.8 in 1989 not 1857. But hey, what do I know... I was only there.

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Timwatts99

09:47 AMJul 12 2009

THERULE7209:32 AMJul 12 2009Yes indeed MRSTEVEN, we can't do a damn thing about nature's changes --------Global warming isn't 'nature's change' it's our change. Human activity is causing the earth to warm. Only dummies and those with an agenda fail to accept this.

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Timwatts99

09:45 AMJul 12 2009

SUTHRNGF wrote: Well what are the social scientist waiting on? They think they can adjust the temperature to any degree they want, and that all knowing all seeing MR. OBAMA can fix the world, why can't they micro manage an earthquake? Maybe it's time they learned who is in control. I've got one word for you GOD!!! ------I've got one word for you. Education. Get one and then maybe you wont be posting stupid, ill informed opinions about science, a subject you clearly know nothing about. Just to get you started on journey of discovery, how is seismology a 'social science' you hopeless dummy?

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Rechoppy92

09:43 AMJul 12 2009

Help me win a scholarship!!! Go to this page and vote for my pictures!! Thanks!! www.brickfish.com/rechoppy92

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