Google on Tuesday announced it is planning to roll out an earthquake early alert system on Android phones. The system, which will first deploy in California, could provide the public with a few seconds warning before an earthquake strikes.

In California, Google partnered with the United States Geological Survey (USGS) and the California Governor’s Office of Emergency Services (Cal OES) to send earthquake alerts directly to Android devices in the state. Those alerts are powered by ShakeAlert, a system that analyzes seismic data from over 700 seismometers installed in California, calculates preliminary magnitudes, and estimates which areas in the state will feel shaking. Since last October, Californians had access to an app called "MyShake" which used Wireless Emergency Alerts (WEA) to disseminate alerts powered by ShakeAlert. The office of California Governor Gavin Newsom says that Google's new system "will use the same data feed to receive and distribute alerts as the state's Earthquake Early Warning System" used by MyShake.

The benefit of Google's new system is that it does not require the installation of a dedicated app. And, if you opt in to the new program, your Android phone will become a mini seismometer as part of the Android Earthquake Alerts System. With millions of Android phones out there, Google could potentially form the largest earthquake detection network on earth. Not every region has a network of seismometers set up as California does, so that’s where Google’s network of Android phones come in. By utilizing a phone’s accelerometers, Android devices could send a signal to an earthquake detection server when it senses an earthquake might be happening.

Google said Android devices are sensitive enough to detect both types of waves — P (primary) wave and S (secondary) wave — associated with earthquakes. People don’t normally feel the P wave which is the first and fastest wave from the epicenter, whereas the S wave, which is slower but usually larger, typically does more damage. Android devices could detect a P wave and then warn people to prepare for the S wave.

Although Google’s system can detect the occurrence, location, and strength of an earthquake using Android phones, the search giant can’t warn users closest to the epicenter in time. As Google explains:

The biggest key thing is that the phones that are nearest to the earthquake can help users away from the earthquake know about it. One of the limitations of the system is that we can’t warn all users before an earthquake reaches them. The users closest to the epicenter of the earthquake just aren’t likely to get a warning in time because we’re not predicting earthquake ahead of time.

In places where there isn’t a sophisticated network of seismometers, Google will use its network of phones to show localized results in Google searches for earthquakes. When you search "earthquake" or "earthquake near me", for example, Google will show relevant results for your area as well as helpful resources on what actions to take after an earthquake. Once Google is happy with the accuracy of its system, it will eventually send out earthquake warnings directly to Android phones.

Android users will not need an OS upgrade to get this feature. Instead, the feature will be integrated into Google Play Services, as we previously reported. Thus, it will be available on the vast majority of Android devices, regardless of the Android OS version. The only exceptions are devices without Google Mobile Services, which includes devices sold in China and new devices from smartphone brands Huawei or Honor.

Earthquake alerts will be tested in California first because of its complex seismometer network. Over the coming year, however, Google said it will bring earthquake alerts to other states and countries around the world. As reported by The Verge, Google also plans to open up an earthquake detection API, but the company wants to first fine-tune the system and minimize false positives.