Many modern day laptops are fitted with what's called an Accelerometer. Accelerometers detect movement and translate it into digital signals. In notebooks, they function as safety devices: When the accelerometer detects that the notebook is in free fall, the computer moves the hard drive head to a safe position in order to minimize the risk of damage when it hits the ground. However, the accelerometers are also accessible to software, so they can be used for games or other applications. As it turns out, one field that already makes extensive use of accelerometers is seismology. Usually these sensors are buried underground, generating much of the data seismologists use to model earthquakes. Thus was born Quake Catcher Network. The two scientists -- joined by Carl Christensen, a programmer with experience in distributed computing -- started in September 2007. Cochran's system makes use of the accelerometers -- tiny motion sensors -- built into many modern notebooks, including Apple's MacBook and Lenovo's ThinkPad, as well as the iPhone and Nintendo's Wii. Distributed computing was made famous by extraterrestrial-scanning network SETI@home, and Cochran uses the same platform, called BOINC, to collect data from the laptops in her project's network. Now all that was needed was to develop algorithms that could differentiate a knee movement from an actual earthquake.

Quake Catcher, its months from even limited release and probably years from issuing warnings. The system is far from perfect. It relies on massive numbers of volunteers that have to stay online. Moreover, it is hard to tune it without large earthquakes. So until then, the team is hoping people sign up, leave their laptops on, and then just hold still.

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