Earthquake early warning system passes major test


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In the seismic annals of California, Monday's magnitude 4.7 earthquake was little more than a footnote. It gave Southern California a small morning jolt but caused no damage and was largely shrugged off by noon.

But in one important way, the quake was highly significant because it marked an advance in California's burgeoning earthquake early warning system.

The quake struck in the desert town of Anza, about 35 miles south of Palm Springs, and hundreds of sensors embedded in the ground immediately sent an alert to seismologists at Caltech in Pasadena. They had 30 seconds' warning before the quake was felt there.

"It was right," said Kate Hutton, a Caltech seismologist. "I sat really still to see if I could feel it and it worked."

The system has been in place for more than a year. But Monday's quake offered a rare opportunity to actually see ? and feel ? whether it worked.

The sensors have warned scientists of numerous quakes, but the vast majority were either too small to feel or too far away to be felt in the Los Angeles area. For example, the sensors gave an early warning of several magnitude 5 quakes last year in Imperial County, but the temblors hit too far away for them to be felt in L.A.

The Anza quake was different.

Even though it measured only magnitude 4.7, its location on solid granite made the shaking stronger and more widespread. People reported to the U.S. Geological Survey that they felt it as far away as Arizona and Central California. At Caltech, computer screens flashed with a 30-second countdown to when the shaking would hit Pasadena. Sure enough, it came on time.

Hutton and others declared the test a success, with some caveats.

The system initially overestimated the quake's magnitude, saying it was 5.2.

The earthquake early warning system is a pilot project for what scientists hope will eventually be a statewide network using thousands of sensors to notify people about imminent shaking from moderate to strong earthquakes.

Backers say an early warning would give utilities time to shut down, trains a chance to slow so they don't derail and workers a chance to move away from hazardous materials or precarious positions. Warnings would be sent to the public through text messages, emails and other special alerts.

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30 seconds before?

thats not enough, i hope they can refine it to give 1 day before.

1 day? so I can make it to New York before a quake strikes? Not going to happen.
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Warnings would be sent to the public through text messages, emails and other special alerts.

umm, no, that would be too slow. I don't know how it is in California, because im not sure if they even have very many tornados there, but here in ohio and the rest of the Midwest sirens placed all over and they are easy to hear. Im sure they do have loud sirens for other major events, but I doubt they carpet the state like they do Midwestern states. It would take only seconds for the sensors to trigger the sirens, and you would know instantly what was happening. With text and emails you may not get it for quite a few minutes, and it would be way to late.

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Who checks e-mails in an instant ?

By the time you clicked, and read it, the quake would be over.

And you couldn't alert workers in time, unless you had some direct, instant alarm.

And I reckon it wouldn't help people riding in an elevator.

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30 seconds before?

thats not enough, i hope they can refine it to give 1 day before.

30 seconds will give you enough time to know you might be fixing to die.

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