Predicting Earthquakes with Smartphones

An interesting example of using a network of smartphones as sensors, and converting that data into a form that can detect earthquakes and then communicate them through the same network. How predictive this system can be in accurate prediction is unclear.  What are the costs of false positives? " ... California Institute of Technology researchers have created an app called CrowdShake  (Still in prototype) that provides early earthquake warnings by converting a smartphone's accelerometer into a seismometer. ... "The accelerometer is already in the phone, the location is something the phone knows, it's not something that a person has to tell it," Guy notes. "And of course your smartphone knows exactly what time it is." .... The accelerometer serves as a sensor gathering vibration data, which is analyzed and then returned to the community with warnings when necessary. ... " 

And also a video on the subject.