Scientists have proposed a means of interpreting the initial, feeble tremors that herald the arrival of a large earthquake to give residents of Southern California advance warning of more violent shaking.
The system theoretically could give anywhere from seconds to tens of seconds of advance notice — enough time to send school children diving below their desks or to cut the flow of gas through pipelines vulnerable to rupture.
Details appear in the current issue of the journal Science. The alarm system would not predict or forecast earthquakes. Instead, it would exploit the staggered way in which energy travels from the underground source of quakes to the surface.
Richard Allen, of the University of Wisconsin-Madison, and Hiroo Kanamori, of CalTech, have developed a way to determine the location, origin, time and — most importantly — magnitude of an earthquake. The system would rely on a network of seismic instruments already deployed across the greater Los Angeles region. The amount of forewarning would depend on the distance of the sensors from an earthquake´s epicenter.