Using the phones of thousands of people, the 'Crowdshake' app can detect earthquakes well in advance. The app constantly compiles the location and movement data of Crowdshake users in order to sense tremors.
If the accelerometer on a bunch of phones in a certain area jump at once, Crowdshake knows that something is wrong. The app can then warn those near the source of the earthquake to get to safety. However, those already caught in the quake don't have much use for the app since it's already too late for them.
The app was created by the Caltech Community Seismic Network as part of Vodafone's Wireless Innovation Project. The Seismic Network developed Crowdshake primarily to service the developing nations community.