Earthquake warning system for Android smartphones

Unlike other natural events, earthquakes cannot be predicted in advance (the IT-alert system is in fact only used for volcanic activity, heavy rainfall, and tsunamis). Since 2020, Google has developed a global warning system that uses billions of Android smartphones. An article published in Science illustrates its features and the results obtained.

Today, it's possible to predict where an earthquake is most likely to strike, but it's still not possible to warn the population in time. The goal is to develop earthquake early warning systems , but national seismic networks are expensive and only available in a few countries, including Japan, China, and Taiwan. In Italy, they exist only on the Naples-Rome railway line and are used to block train traffic.

Beginning in 2020 in the United States and subsequently in other countries, Google developed an earthquake detection system that uses Android smartphones . The system has detected thousands of earthquakes and sent alerts to millions of people in nearly 100 countries.

The sensor that detects an earthquake is the accelerometer . When a smartphone placed on a flat surface detects P-waves (the faster waves that cause wave motion), a signal is sent to Google's server along with the approximate geographic location.

The system analyzes data from millions of smartphones to confirm the earthquake, estimating its location and intensity. The goal is to alert users of the arrival of a subsequent S-wave (the slower ones that cause jolting and more catastrophic movements).

The system then sends two alerts to users near the epicenter, one for minor earthquakes (similar to a notification but with a different sound) and one for stronger earthquakes (which takes up the entire screen with a louder sound). There's no need to install additional apps because the feature is built into the operating system (specifically, Google Play Services), but geolocation must be enabled. Unfortunately, as you can see on the map, it's not available in Italy .

Since April 2021, over 18,000 earthquakes between magnitude 1.9 and magnitude 7.8 have been detected. Over 790 million alerts have been sent for approximately 2,000 earthquakes. For the magnitude 7.2 earthquake in Turkey in April 2025, the first alert was sent approximately 8 seconds after the shock began.

The main challenge is estimating the earthquake's strength. Users might not be alerted in time or receive a false positive alert (such as a subway passing by the building). Errors are minimized precisely because signals from millions of smartphones are arriving.