2006年VOA标准英语-US Scientists Work on Computer Model to Detect（在线收听）

By Anthony Stokes
Washington, D.C.
14 July 2006
 
watch earthquake report

  
  
U.S. geological experts are working to develop a computer model that can better detect an earthquake and warn people in advance.  VOA's Anthony Stokes looks at how the early warning system in the United States compares to those of other countries. 

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It is a common bond shared by countries around the world - the likelihood that natural disasters, such as earthquakes, can strike at any time.  But what is uncommon is that some countries have installed underground sensors to detect an earthquake and send out early warnings to prepare people. 

The system works because electronic signals can be sent to a computer much faster than the shock waves that move through the earth. 

Such systems are in place in Japan, Mexico, Taiwan and Turkey.  In the United States, scientists at the California Institute for Technology are also working on ways to warn people just before a quake.  

Tom Heaton  
  
Tom Heaton, an earthquake engineer at Cal Tech, says the system is still years away.  "We have about 150 sensors that are appropriate for this task out in southern California at the moment.  To really run this correctly, my guess is it would take more like 600 sensors."

Work on the early warning software is just beginning, but researchers believe within five to 10 years, warnings could be transmitted to cell phones.  Heaton hopes the new computer system can give residents a warning of at least 30 to 60 seconds.  While that is not a lot of time, Heaton describes a scenario in which a short warning could make a big difference.

"I don't know about you," says Heaton, "but I don't want to be stuck in an elevator in an earthquake, so the elevator would go to the closest floor and open the door."

But in southern California, fault lines are everywhere, making it a challenge for the sensors to detect an earthquake. "In many of those instances, you'll be near the epicenter and this system won't help you at all," predicts Heaton.  "You'll just feel the earthquake as severe shaking."

Scientists hope the new model will prepare them in case of another massive earthquake like the one that hit San Francisco in 1906, killing 3,000 people.  The U.S. Geological Society is also using computer models to recreate the ground motions from the 1906 quake, to better understand the distribution of shaking and damage along more than 480 kilometers of the San Andreas fault.  The results of these investigations could help U.S. scientists develop early warning systems like those of other countries.