When an earthquake strikes, seismic waves spread from the
epicenter, following the patchwork quilt of faults and geology
in California, for example. The violent shaking these waves may
trigger can topple buildings, rupture water mains and wreak
havoc on industrial infrastructure. But by making quick computer
analyses in seismographic stations near the epicenter, warnings
can be relayed in seconds, allowing people to take safety
precautions and critical infrastructure to be shut down,
scientists reported this week at the fall conference of the
American Geophysical Union in San Francisco. "What we're doing
with early warning is predicting the ground motion after we know
the earthquake is underway," says seismologist Richard Allen of
the University of California, Berkeley. "Any computerized system
can start to do things very rapidly, rapidly enough so we can
implement our response before the ground stops shaking." Such a
system, developed by Allen and his colleagues, is currently
being tested in California's rou