Seconds Before the Big One

Monday, March 14th, 2011

Earthquake alarms could provide warning seconds before the Big One:

Within seconds of an earthquake’s first subtle motions, scientists can now predict with some certainty how strong and widespread the shaking will be. By integrating new science with modern communications technologies, the authorities could get a few tens of seconds’ warning, perhaps even half a minute, to those in harm’s way. That may not sound like much, but it is enough to send shutdown warnings to power plants and rail networks, automatically open elevator doors and alert firefighters.

The Loma Prieta quake was centered south of the Bay in the rugged Santa Cruz Mountains. After the ground started to shake, it took more than 30 seconds for the damaging vibrations to travel the 60 miles to San Francisco and Oakland, the scenes of more than 80 percent of the fatalities. If an earthquake early-warning system had existed back then, it could have provided perhaps a 20-second warning to the heart of the region. This is enough time to slow and stop trains, issue “go around” commands to airplanes on final approach and turn street­lights red—preventing cars from entering hazardous structures such as bridges and tunnels. Workers in hazardous work environments could move to safe zones, and sensitive equipment could enter a hold mode, reducing damage and loss. Schoolchildren and office workers could get under desks before the shaking arrived. The region would be ready to ride out the violence to come.

Such networks are being deployed all over the world in locations as diverse as Mexico, Taiwan, Turkey and Romania. Japan’s system is among the most advanced. The nationwide network issues warnings via most television and radio stations, several cell phone providers, and the public address system of malls and other public spaces. In the three and a half years since the system came online, more than a dozen earthquakes have already triggered widespread alerts. People in factories, schools, trains and automobiles were given a few precious moments to prepare; following the alerts, there were no reports of panic or highway accidents. The U.S. is behind the rest of the world, but a new test bed being deployed in California should soon lead to a full-scale warning system in that fault-ridden state.

That piece, by the way, was scheduled to come out in next month’s Scientific American, but they put it up online early, for obvious reasons.

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