Your smartphone can already warn you about earthquakes. UC Berkeley, however, is going one step further: it wants your phone to help detect those quakes. The school has released an Android app, MyShake, that uses your phone's motion sensors to detect the telltale signs of tremors and combine that with the data from every other user. For all intents and purposes, you become part of a crowdsourced seismic station network -- you can confirm a quake just by leaving your phone turned on. That could be a big help when there aren't enough fixed stations to trigger an alert through conventional apps.
MyShake might even give you a heads-up in the future. Once the software is known to be trustworthy, it could send early warnings to nearby areas and even provide a countdown to help you find a safe area in time. And yes, there are plans for an iOS app as well. The system is only as effective as the number of people using it (a handful of testers won't accomplish much), but it could prove to be a life-saving tool if it really catches on.