Taiwan Quake Floods Scientists with Data
Monastersky, R., Science News
As residents of Taiwan try to piece together their lives in the aftermath of last week's catastrophic temblor, scientists are starting to sift through mountains of seismic recordings that promise to make this event the most closely documented earthquake in history.
"It is probably the best data set ever collected for an earthquake," says Lucile M. Jones, a seismologist with the U.S. Geological Survey in Pasadena, Calif.
"It's almost like a gold mine in terms of instrumental recordings," agrees Ta-Liang Teng, a seismologist at the University of Southern California in Los Angeles.
In 1990, Teng helped persuade Taiwan to spend $40 million in setting up a nationwide network of more than 1,000 seismic recording instruments, a system unparalleled elsewhere in the world. The Taiwanese Central Weather Bureau completed the network in 1996, with some critics saying that decades would pass before it recorded a direct hit from a major tremor.
At 1:47 a.m. on Sept. 21, the magnitude 7.6 earthquake struck the heart of the network, near the city of Chi-Chi at the center of the island. Within 102 seconds, the seismic system determined the quake's location, size, and basic characteristics, according to data from the Central Weather Bureau. The information was published on the Internet by William H.K. Lee of the USGS in Menlo Park, Calif., who formerly managed a seismic network for USGS and also played a role in setting up the Taiwanese system.
The web of instruments on the island follows a strategy different from that of traditional networks in the United States. Designed largely by seismological researchers, the U.S. networks in California and other parts of the country were built to capture all earthquakes, powerful and puny. To record distant tremors, seismologists must install their instruments in quiet sites far from traffic, waves, and other sources of vibrations unrelated to earthquakes.
The Taiwanese system, in contrast, puts most of the instruments in urban areas to record how different parts of cities shake during quakes. …