Android detects earthquakes using motion signals from phones

When you turn your phone sideways, the screen rotates accordingly. This is because the sensor inside the device detects movement. The same sensor can also respond when the floor shakes. Google created a network that detects earthquakes by collecting signals from multiple Android phones.

The starting point for the Android Earthquake Alerts System, released in August 2020, was devices that people already had. Even in areas where it is difficult to install new professional seismographs, if cell phones are widely placed, the sensors inside them can collect clues about movement.

A bumped desk or shaking ground?

Acceleration sensors read changes in the device's movement. It reacts even if you drop your cell phone or touch the desk, so it is difficult to judge that it is an earthquake based on a single signal. According to Google's explanation, the device sends suspected earthquake signals and the approximate location to the server, and the server analyzes several nearby signals together.

If several phones shake at similar times, it becomes a clue to check the movement in the area. This is a detection method that is distinct from the ShakeAlert alert in the western United States, which delivers information from a professional observation network to Android. Cell phone observation is introduced as a technology that complements the official warning system.

An alert before the strongest shaking

Early warning is not a function that determines the time of occurrence of an earthquake before it occurs. It detects the first waves after an earthquake begins and sends an alert before stronger shaking reaches other areas. It takes time to send and analyze signals, so warnings may arrive late or provide very little lead time near the epicenter.

It is difficult to accurately estimate the size with only the first information. If you wait longer, there will be more data to make a decision, but the time to send notifications will decrease. Providing information quickly and accurately where needed go hand in hand.

The few seconds saved by the notification on the screen

In a study introduced in July 2025, Google Research described the magnitude 6.2 earthquake in Turkiye in April of that year. The first warning was sent out 8 seconds after the earthquake began, giving people who experienced moderate to strong shaking a few seconds to 20 seconds to spare. The earthquake had already begun, but in some areas alerts arrived before the shaking.

To receive notifications from your device, a communication connection and related alarm and location settings are required. The available time also varies depending on the location and detection conditions of the earthquake. The lead times reported in this example are not guaranteed for every earthquake.

A component that detects small movements in one phone can, when signals from many phones are combined, help identify shaking across an area. In the Türkiye example, the first alert went out eight seconds after the earthquake began. This was not prediction before the event; it was an opportunity to send a warning before shaking already under way reached other locations.