U.S. scientists test early warning system for earthquakes

by William Atkins

Friday, 11 July 2008

Page 1 of 3 ! An early warning system for the detection of upcoming earthquakes may be possible with the use of very sensitive new equipment developed by U.S. scientists. So far, they have been able to predict, hours in advance, two small earthquakes along the San Andres Fault in California. The researchers involved with the early warning earthquake system are Fenglin Niu and Xin Cheng, both of the Department of Earth Science at Rice University (Houston, Texas); Paul G. Silver, from the Department of Terrestrial Magnetism, Carnegie Institution of Washington (Washington, D.C.); and Thomas M. Daley and Ernest L. Maher, both from the Earth Sciences Division, Lawrence Berkeley National Laboratory (Berkeley, California). The new, technically advanced system detects a type of seismic wave that travel the fastest when a earthquake is first developing. This “P-wave,” or primary wave, is an elastic type of seismic wave that is able to travel through elastic solids and liquids (such as those found within the Earth), along with gasses. The slower moving waves are called S-waves, or secondary waves. Instead of being able to predict earthquakes only a few seconds before they happen, this new technology has the potential of allowing scientists to predict earthquakes hours in advance—if further studies bear out the accuracy of the new system. The abstract to their paper states, “Measuring stress changes within seismically active fault zones has been a long-sought goal of seismology. One approach is to exploit the stress dependence of seismic wave velocity, and we have investigated this in an active source cross-well experiment at the San Andreas Fault Observatory at Depth (SAFOD) drill site.” The new technology functions differently than the older, less accurate one. Paul Silver, a researcher in the study, states, "Detecting stress changes before an earthquake has been the Holy Grail in earthquake seismology for years and has motivated our research. Researchers have been trying to precisely and continuously measure these velocity changes for decades, but it has been possible only recently, with improved technology, to obtain the necessary precision and reliability." [Science Daily: “Early Warning System For Earthquakes: Seismic 'Stress Meter' Warned Of Earthquake 10 Hours In Advance”] The researchers performed their research in a two-month period from late 2005 to early 2006 near Parkfield, California, located between Los Angeles and San Francisco, California. How did they perform their experiment within the interior of the Earth? Please read on. << First page <   1 2 3 Next page > Last page - Post your comment >>

 

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