Billions of phones can detect and warn nearby earthquakes

Your phone can be among the billions of devices around the world that already serve as an earthquake system at the start of alert in dozens of countries.

Since its launch in 2020, the Android Earthquake system alerts from Google has extended to allow users of Android and SmartWatch phones of 2.3 billion to receive alerts on nearby seismic jitters, compared to 300 million people who could obtain such alerts from other sources, according to a new study by Google researchers. But phones are not only warnings – their sensors also help detect earthquakes.

“Billions of Android devices work together and act as mini-seismometers to create the largest earthquake detection network in the world,” said Richard Allen at the University of California in Berkeley, who is also a guest researcher at Google.

The system developed by Allen and its colleagues analyze the vibrations detected by accelerometers in Android phones and smart watches. Together, this network of sensors can indicate the size of an earthquake and which telephone users are close to the danger enough to receive a warning message.

The Google system informs people when it detects an earthquake with a magnitude of 4.5 or more. But the system “cannot detect all earthquakes” because it requires that a sufficiently large number of phones is sufficiently close to the earthquake, explains Allen. For example, it does not detect earthquakes from most of the ocean ridges, although it can detect seismic events occurring tens hundreds of kilometers offshore.

One of the biggest challenges was to quickly and precisely determine the extent of each seismic event. Researchers have improved the system’s earthquake detection algorithm over the years by developing regional models to better represent local tectonic movements and taking into account variable sensitivities of sensors among different Android phones.

Google’s global system is now as precise as the Shakelert system that covers the American West Coast and the Japan -Meteorological Society Earthquake program, explains Allen. He notes that the Google project is intended to complete, rather than replacing, systems based on the seismometer like these – it integrates and even delivers Shakelert warnings for people on the west coast. “But the reality is that many regions subject to earthquakes do not have the regional seismic networks necessary to provide warnings,” explains Allen.

The Google system provides a “single source of information” for countries without an earthquake at the start of the alert, explains Katsu Goda at Western University in Canada, which is not involved in the initiative. It also reaches more people in total, even when other national or regional alert systems are available, he says.

The system currently provides alerts on 98 countries and territories, especially the United States but not the United Kingdom. “We have generally focused on countries that have a greater historical seismic risk without having an existing earthquake solution at the start of opening,” explains Marc Stogaitis at Google.

According to the new study, which analyzed the performance and precision of the program, the system had issued alerts for 1279 seismic events in March 2024, with only three false alerts. Two of these false alerts involved thunderstorms and one was triggered by an unrelated mass notification event which vibrated several phones. The team has since updated the detection algorithm to avoid such false triggers.

Most Android devices are chosen to participate in the telephone -based seismometer network and receive alerts on the default earthquakes, although users can change these two parameters. In a survey on Google users, more than a third of the system participants received telephone alerts before feeling tremors – and most people who obtained alerts describe them as very useful.

If users of the Android phone remain registered with alerts, these are available in two types. More urgent action alerts are designed to encourage people to take protective measures, such as “fall, cover and keep”. But they often provide only a few seconds of early warning because they do not come out until the system predicts strong tremors. On the other hand, less intrusive, which provide more general information, can happen from tens of seconds before users of the phone feel an earthquake.

“The physics of earthquakes dictates that there will be less warning before the tremors stronger than weaker tremors,” explains Stogaitis. “But we continue to explore the modification of our alert strategy to improve warning times in future earthquakes.”