IBM has developed a system to track earthquakes via the sensors in your hard drive, a technology that has existed since 2006.
IBM was granted patent #7,693,663: "System and method for detection of earthquakes and tsunamis, and hierarchical analysis, threat classification, and interface to warning systems", which was applied for in April 2007 and granted in April 2010.
The patent and technology uses the sensor in your laptop's hard disk to detect seismic vibration, and to communicate the data back up to the Internet, at faster speeds than the earthquake can travel. Hard drives have contained these sensors since about 2004, fixing the read-write head in place to prevent scratching the disc media in case the laptop is jiggled or actually falls.
The information can be especially useful to track and predict the path of tsunamis, giving people near the projected affected area vital minutes to escape. It can also assist first responders, said Bob Friedlander, a master inventor for IBM.