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Android phones are one of many new global safety tools that gives people early warnings when earthquakes happen. Since 2020, Google has run a system that turns Android devices into small seismometers using their built-in sensors.

These phones can pick up early vibrations from earthquakes and send that data to Google鈥檚 servers. When the system detects an earthquake, it alerts people who may be at risk.

The alert system works by picking up the first wave of an earthquake, known as the P-wave. This wave travels faster than the stronger and more damaging S-wave that follows. If a group of phones detects shaking, the system quickly checks the data to estimate the earthquake鈥檚 location and size.

If the shaking looks serious, users receive a warning before the stronger wave hits. People can then take cover or move away from dangerous spots like glass, shelves or heavy furniture.

The system sends out 2 types of warnings. The BeAware alert is used for lighter shaking and the TakeAction alert is used for stronger shaking. The TakeAction alert appears across the phone鈥檚 screen and plays a loud sound.

To get these warnings, users need to have their location settings and internet connection switched on. People who do not want alerts can turn them off in their phone鈥檚 settings.

How Far Is The Android Earthquake Alerts System’s Reach?

According to Google, their alert system is now active in 98 countries. In 2019, about 250 million people had access to earthquake warnings. That number has now grown to 2.5 billion, mainly because of this Android system. The phones work together to detect shaking, and Google uses this network to send alerts to people around the world.

The system has detected over 18,000 earthquakes so far. From those, over 2,000 were big enough to trigger warnings. In total, about 790 million alerts have been sent. Some earthquakes were too small or happened in places where not enough phones could pick them up. Earthquakes in the middle of oceans, for example, often go undetected.

Marc Stogaitis, a principal software engineer at Android, said that the system uses phones to supplement official earthquake warning networks. These traditional networks usually need expensive seismic equipment, which is not available in many earthquake-prone places. The phone-based system is meant to help fill those gaps.

Does The System Work During Real Earthquakes?

There are 3 recent earthquakes that show how the Android system performs in real conditions. In 2023 in the Philippines a magnitude 6.7 earthquake brought about the first alert just over 18 seconds after it began. People near the epicentre got about 15 seconds to make movements. Those who were not as close had as much as a minute. About 2.5 million people received alerts.

And in November 2023 a magnitude 5.7 earthquake in Nepal triggered alerts within 15.6 seconds. 10 million alerts were sent, giving people warning times ranging from 10 to 60 seconds. In Turkey, a 6.2 earthquake in April this year led to over 16 million alerts being sent. People near the shaking had between a few seconds and 20 seconds to prepare.

Richard Allen, a visiting researcher at Google and professor at the University of California, Berkeley, said the system works best when many phones are close to the shaking. It cannot detect earthquakes in areas where phones are sparse or where people are not using Androids. This is a very useful tool, and shows how tech can be used for good.