A new phone app uses vibrations from smartphonesto alert people about earthquakes.The phone app recognizes sudden shaking of the earth's surfacethrough sensors in smartphones.The new app is called MyShake.It is the work of four researchers at the University of California, Berkeley.They said they created a worldwide warning systemthat would inform people and give them time to prepare.Other earthquake apps include QuakeFeed, Quakes and Earthquake.They show where earthquakes have happened,at what strength, and the aftershocks.Those use data from the U.S. Geological Survey.The MyShake app is available only for Android phones.Smart phones are equipped with accelerometers.These instruments measure movement, like that of a car or airplane.They can also measure the shaking of a machine, building or other structure.Accelerometers are used in activity trackersand apps that count steps or other exercise.They also are used in global positioning system apps, also called GPS.MyShake uses phone accelerometers to measure seismic activity.It has been programmed to know the differencebetween normal activity and earthquake movement.The software developers say their app is right 93 percent of the time.A smartphone sends seismic information to the app developers.If the developers receive several notifications from one area,it recognizes that an earthquake may be taking place or will take place soon.Using information sent from the app,the network then estimates the locationand strength of the quake in real time.MyShake can record magnitude 5.0 earthquakesat distances of 10 kilometers or less.MyShake uses very little power, according to its developers.Only when seismic activity is sensed by the appdoes it become active and sends data to the network.The app works best when your phone is resting on a flat surface, like a table.The developers hope that MyShake can add to informationcollected by the U.S. Geological Survey.That U.S. agency has created the Earthquake Early Warning System,also known as the EEW.The EEW has deployed sensors for measuring quakes in many areas.In places where no such equipment exists,MyShake may be the only method of early quake detection.The app also shows ways to stay safer during an earthquake.The developers say it will become more effective as more people use it."Our goal is to build a worldwide seismic networkand use the data to reduce the effects of earthquakeson us as individuals and on society as a whole," say the researchers.The developers say they hope to add a featurethat would warn people about a possible tsunami,or the huge waves that happen after an earthquake.