Quake-Catcher Network

The Quake-Catcher Network at Stanford is setting up a network of people with apple laptops that have accelerometers in them to use for earthquake detection. Accelerometers are devices that sense motion. They're used in the Wii controllers and laptops have had them for a few years to detect falls and lock the hard drives before impact to prevent damage.

This is similar to SETI@home using spare computing cycles from volunteer home computers to search for extraterrestrial life and to other projects working on hard problems like protein folding. The difference is using the new hardware and using the volunteer machines as a sensor network instead of just spare computing cycles. It's closer to 911 systems letting people use camera phones to report crimes

"The client- and server-side software rapidly monitors incoming seismic signals, detects the magnitudes and locations of significant earthquakes, and may even provide early warnings to other computers and users before they can feel the earthquake. The open-source software will provide the client-user with a screen-saver displaying seismic data recorded on their laptop, recently detected earthquakes, and general information about earthquakes and the geosciences."

Yes the software can differentiate between bumps and drops and earthquakes and small tremors. Part of that undoubtably depends on coordinating signals from a large number of machines.