On June 24, 2026, two huge earthquakes struck Venezuela, a country with no national earthquake warning system. Only about seven countries in the world run government-operated systems that can issue such alerts. Yet roughly 11.4 million Android phones in the affected area lit up with an alert seconds before the shaking arrived. One user wrote online that the alert helped them get out into the garden in time. Nobody has an official count of lives saved. A widely shared claim of “thousands” couldn’t be verified, but a Harvard write-up estimated that perhaps several hundred people were saved.

So how did a phone know? Every Android phone has a small sensor called an accelerometer, which detects movement and shaking. Google’s Android Earthquake Alerts system, developed with engineers at the University of California, Berkeley, uses it to turn each phone into a mini seismometer. When a quake starts, phones near the centre feel the shaking and send a signal to Google’s servers. Google combines signals from many phones to estimate where the quake is and how strong it is, then sends alerts to phones farther away that haven’t felt anything yet.

The alert can arrive in time because earthquakes send out two kinds of waves. The first are fast and weaker. The second, called S-waves, are slower and cause most of the damage. Data travels faster than those damaging waves, so the alert can reach you before they do. That gives you a few seconds to drop, take cover, or step outside, and in a big earthquake even a few seconds can matter.

The scale of the system is remarkable. Android phones make up an estimated 70% of smartphones worldwide, which is what makes the network so large. By mid-2025 it had detected over 18,000 earthquakes, issued alerts for more than 2,000 significant ones, and sent around 790 million alerts in total. When a magnitude 5.7 quake hit Nepal in 2023, it sent over 10 million alerts, with the first going out about 15.6 seconds after the quake. A study published in the journal *Science* in July 2025 found that its performance is comparable to established national warning systems. It began in the United States and has now expanded from 98 countries and regions to more than 200.

There are two types of alerts. “BeAware” is for light shaking, and “TakeAction” is for strong shaking and plays a loud sound that overrides silent mode. The feature is on by default on most Android phones, but it needs an internet connection and location services. You can check it under Settings, then Safety and emergency.