Planned quake alarm would allow seconds to prepare

WAIKOLOA, Hawaii » A group of University of California scientists is developing a system that could send out warnings 20 seconds before an earthquake strikes.

The Earthquake Alarm Systems, or ElarmS, and a plea for better collaboration were among the highlights at last week's meeting of the Seismological Society of America, where nearly 500 seismologists gathered at the Hilton Waikoloa Village.

The annual meeting coincided with the passing of six months since Hawaii's Oct. 15 quakes. The 6.7-magnitude temblor under Kiholo Bay on the Big Island was the strongest quake in the nation in 2006. It was centered at a depth of 24 miles, deep enough not to trigger a tsunami. An ElarmS system might have alerted residents that the shaking was coming.

The ElarmS system has its roots in Japan in the 1960s, when authorities sought to limit damage to high-speed trains during earthquakes. Japan, Taiwan and Mexico now have similar early warning systems.

The magnitude of an earthquake can be estimated within one second of the first seismic reading, said University of California-Berkeley assistant professor Richard Allen. At six seconds, computers can predict the reach of the quake and send out warnings.

Since last year the team has mapped 160 seismic events of between magnitude 3.0 and 5.0 in Northern California. Most were detected within 10 seconds of origin.

The amount of warning time people would receive depends on their proximity to the epicenter. The farther from the event's origin, the more warning time would be available, perhaps as much as 50 seconds.

"An early warning system will help many people in many earthquakes," Allen said. "We're looking at a 10- to 20-second window."

That can be long enough for people to seek cover, he said.

In addition, the system eventually could be fully automated. Drivers could be warned not to pull over, planes not to land, trains halted on the tracks, gas lines and power plants shut down, machinery shut off.

"It's more of a way to reduce hazards," Allen said. "That's really our expectation. Unfortunately, I do not believe we will be predicting earthquakes in the foreseeable future."

Still, the critical component of the system will be getting the message out, he said.

"We have the information before most people even feel the first vibrations," he said. "What we need is a robust communication system."