China Lacks Earthquake Early-Warning System
Earthquake Alerts Are Still in Their Infancy.
One problem with early-warning systems is that they require many sensors distributed over a wide geographic area; the greater the number of sensors, the more precise the calculation of the quake's epicenter and magnitude, and the earlier the warning. To fill in gaps left by conventional seismic instruments, some researchers have proposed exploiting sensors inside laptop computers to allow them to serve as distributed P-wave sensors. While laptop sensors are not very sensitive, their great numbers may have value, Kanamori says. "It is a matter of engineering, how you put together the laptops. If you have a large quantity, maybe it can be helpful."
Had a warning system been in place in China before Monday's earthquake, the benefits may have been blunted by the poor quality of some of the buildings that collapsed. "There is no early-warning system implemented there, but even if it was, I don't know how effective it might be in that circumstance, when you have so many people living in bad buildings," Kanamori says.
Even a sophisticated system like Japan's is, of course, limited by the short warning time. For example, in 2004, a 6.5-magnitude earthquake struck in central Japan. A bullet train was running in the area, and thanks to the train-warning system, it shut off its power and hit the brakes. But the quake struck the tracks three seconds later, before the train had lost much velocity. It derailed anyway, the first such derailment in the bullet train's 40-year history.
Several European countries and the United States are conducting research on earthquake early-warning systems. But while a group of universities in California has developed and tested a warning network, no governmental system is in place to alert the public. "There hasn't been a major seismic event, and that is very lucky," Kanamori says. "But without that, there is no real incentive to start doing" public warnings.
- 1 |
- 2
