BACK IN 2016, Ars Technica documented a fascinating use of our smartphones for a set of sensors: earthquake detection. The accelerometers on your phone allow a passable seismometer, so you can locate earthquakes so alert users about the shocks passing through the landscape with location data and enough users. In addition to funding from California, the University of California, Berkeley, has developed an app called MyShake and built an inexpensive, effective earthquake detection network. At least for people who installed the app, it was born.

How if the software didn’t have to be installed? What if earthquake detection has only been implemented into the operating system? That’s the query Google will respond with the Android Earthquake Alerts Program announcement on Tuesday. Through rolling earthquake detection, Google will create what it calls “the largest earthquake detection network in the world,” on almost every Google Play Android phone. Here’s the presentation meat:

Both smartphones have tiny accelerometers that can sense earthquakes. We are also highly able to detect the P-wave, the first wave that occurs from an earthquake that is usually much less destructive than the S-wave that comes later. When the phone detects something that it thinks could be an earthquake, it sends a warning and a rough location of where it happened on our earthquake detection server. The computer then incorporates information from several phones to determine when an earthquake happens. We are primarily competing toward the pace of an earthquake (which is approximately the speed at which signals from phone travel). And luckily for us, light speed is much quicker!

This “race” frequently only works a minute or so of warning, but typically that’s enough to duck and cover when you get the message.

In California, Android earthquake monitoring is a partnership between Google and ShakeAlert, the back-end device that MyShake customers use. ShakeAlert in California blends smartphone readings with a conventional seismometer network, and now Android will be a new ShakeAlert user to pump data and view alert from it.

Google’s in-house Android Earthquake warning program would be on earthquake watch for everyone else in the world without such an advanced Earthquake monitoring network. The company says, “To begin, we’ll use this technology to provide a quick, accurate look at the affected area on Google Search. You find relevant results for you, along with helpful, reliable tools for what you can do in your area following an earthquake when you look up ‘earthquake’ or ‘earthquake near me.'”

The functionality is distributed to and from all Android phones running version 5.0 via Google Play Services. In comparison to major system updates that take several years for most Android phones, Google Play Services is centrally delivered by Google, and in a matter of weeks, it can reach any active Android phone (other than non-Google apps in China). Android 5.0 means that 94 per cent of Google Play’s 2.5 billion Android users have access to the feature. The functionality is disabled (and deactivated) by changing the settings on Android through the Google Location Services switch (also known as Google Location Accuracy), which reads, “Google can periodically collect location data and use it anonymously to improve location accuracy and location-based services.” Earthquake detection uses your coarse position data at the urban level, not your precise location data.

It sounds like Google first needs to gather some data before proactive warnings roll out around the world. Proactive earthquake alarms will be available only in California now (with a ShakeAlert and data set already in place) and Google says: “You should anticipate earthquake notifications to be sent to more states and countries using Android-based earthquake detection in the coming year.”