Earthquake researchers in California hope to take advantage of the motion sensors in laptops to create an earthquake-sensing network. By putting computers in homes and businesses to work as seismic monitors, the researchers hope to pull together a wealth of information on major quakes, and perhaps even offer early warnings, giving a few seconds' notice of a potentially devastating quake.

The Quake Catcher Network (QCN) is in the beta testing stage, with links to several hundred laptops. It's a distributed computing network, like SETI@home, which searches for intelligent signals from space, and Folding@Home, which focuses on protein folding. Machines in the earthquake network would monitor motion and report big shakes to a central server. If a horde of reports came in from a particular area, it could indicate an earthquake. The network will initially focus on the quake-prone San Francisco Bay and the Greater Los Angeles Basin areas of California.

"Were not trying to predict earthquakes, we're trying to measure them very rapidly and get the information out before damage is done to large populations," says Jesse Lawrence, an earthquake seismologist at Stanford University. He's working on the project with Elizabeth Cochran, an assistant professor of seismology at the University of California, Riverside, who came up with the idea, and other collaborators at both universities.

Hundreds of sophisticated seismometers are already in place in California, but they're spaced relatively far apart. The new distributed network wouldn't replace those, says Paul Davis, a professor of geology at the University of California, Los Angeles, but "it would fill in the gaps."

The QCN team has developed software that turns Mac laptops into seismic sensors and displays seismic data on a screensaver. They plan to later release a Windows version. Apple laptops manufactured since 2005 are outfitted with accelerometers, as are many IBM (now Lenovo), Acer, and HP laptops. They detect sudden acceleration--as when a laptop falls from a table, for instance--and brace the hard drive for impact.

Desktop computers don't have built-in accelerometers, but they can easily be outfitted with inexpensive USB shake sensors, Lawrence says, which are already used in the automotive industry to develop and test safety devices such as airbags. Lawrence and his collaborators hope to distribute USB shake sensors to schools so students can be part of the network.

The Quake Catcher Network's software will analyze shakes sensed by a computer's accelerometer and report only big movements to the central server, ignoring the vibrations from a passing truck, a bump to a table, or even a minor earthquake. The pattern of signals received by the server should allow the network to recognize a significant earthquake, Lawrence says. The location of networked computers will be identified by their IP addresses and from reports from users.