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Broadcast: May 16, 2003
By George Grow
This is the VOA Special English Environment Report.
Scientists in the United States have developed a computer program that they say could provide an early warning of major earthquakes. The new system is designed to give a warning seconds before an earthquake strikes.
That may not sound like very long. However, it could give people time to get under a table or take shelter someplace else. The flow of electric power or gas could be cut. Air traffic controllers could warn away pilots. Even so-called "smart buildings" could be designed to get ready.
Richard Allen of the University of Wisconsin and Hiroo Kanamori of the California Institute of Technology developed the program. They call it the Earthquake Alarm System. A report published in Science magazine describes it.
The system uses a mathematical program to measure information collected by instruments deployed across the Los Angeles area. Southern California already has more than one-hundred-fifty seismic stations that measure movements within the ground. The information they collect is sent to a high-speed computer.
The two scientists are still developing their system. But Professor Allen says it could be put in place in other areas after testing is completed.
An earthquake shakes the ground with two kinds of waves. The new system uses information from a low-energy wave that moves quickly but causes little damage. Experts call this the P-wave. The slower but stronger S-wave is the main threat to life and property.
Japan already has a system based on P-waves. There, the warnings are used to slow down high-speed bullet trains. Other countries have warning systems that measure S-waves.
The new system is designed to estimate the strength of the earthquake once the shaking starts. Areas directly above the center of the earthquake would have the least warning. Distant places might have as long as forty seconds.
The scientists are still testing their proposed system in the Los Angeles area. Professor Allen notes that an early warning system for earthquakes would require a major campaign of public education. Then, too, is the problem of the possibility of false alarms.
This VOA Special English Environment Report was written by George Grow.
1. earthquake [5E:WkweIk] n. 地震
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