U.S. Tests Early Warning System For Earthquakes

Sep 20, 2011
Originally published on September 20, 2011 12:55 pm

A few seconds doesn't seem like much, but scientists say an early detection system that gives the public five, 10, up to 40 seconds of warning before an earthquake could save lives.

The AP reports today that the United States is working on a system that does just that:

After years of lagging behind Japan, Mexico and other quake-prone countries, the U.S. government has been quietly testing an earthquake early warning system in California since February. ...

The alert system is still crude and messages are not yet broadcast to residents or businesses. With more testing and funding, researchers hope to build a public warning system similar to the Japanese that has been credited with saving lives during the March 11 magnitude-9 disaster.

Since earthquakes are unpredictable, supporters of early warning say it's the next best thing to prepare people and the commercial sector before the ground rocks. Even a 5-second advance notice can be precious, they contend.

"You want to get under a sturdy table before things start falling off the wall," said University of California, Berkeley seismologist Richard Allen, a project participant. "We don't want people to start running out of buildings."

So how does it work exactly? The system senses the first waves — "P" waves, which are less dangerous than the subsequent "S" waves — of an earthquake. As soon as that happens, it sends warnings.

Depending on how far you are from the epicenter you could receive a few seconds' notice. The Daily Mail in the U.K. explains that when Japan was hit by the massive earthquake and tsunami in March, millions received between five to 40 seconds of warning. Tokyo, the paper reports, was 230 miles from the epicenter and it got "about 10 to 30 seconds notice before high-rises swayed."

That doesn't seem like much, but it's enough time so that "trains can be stopped, planes grounded, power plants prepared and schoolchildren kept safe..."

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