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Earthquake warning on smartphone ! This is how Google’s alert system works

On August, Google had lauched its earthquake detection system. In that system  there is the feature of earthquake alert . But the alert system is now only available in California .

How the system works ?

According to Google , the accelerometer present in android phone measure P-wave . P wave is the initial wave that comes after earthquake . When the phone detect shakes or vibrations , it sends that information to central server which determine whether that detected information is earthquake or not. 

For the determination the server checks single data coming from diverse mobile devices. Google collaborated with the United States Geological Survey (USGS) and California Governor’s Office of Emergency Services (Cal OES) to send earthquake alerts, powered by ShakeAlert®, directly to Android devices in California.


Developed by the nation’s leading seismologists, the ShakeAlert system uses signals from more than 700 seismometers installed across the state by USGS, Cal OES, University of California Berkeley, and the California Institute of Technology. A few seconds of warning can make a difference in giving you time to drop, cover, and hold on before the shaking arrives.

How earthquake alert technology works? How to use it ?

When an earthquake is felt , the two active seismic wave  ie P wave and S wave pass through the epicenter. S wave is comparatevely 2km slower in speeed , more destructive and has higher amplitude than P wave .

 The earthquake alert works by detecting P waves . It detects the P wave coming from seismometer which is near the earthquake epicenter. Then that signal will pass in light speed , finally reach to computer system resulting the analysis of the earthquake’s location and the travel of P and S wave in our location.

In this way system alert us . It tries to alert about how much time will the the S wave take  quickly as soon as possible. But if we are in epicenter we are in Blind Zone and will not be able to get the alert .

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