Google Taps Billions of Android Phones to Build Global Earthquake Detection Network
Between 2021 and 2024, Google quietly turned more than two billion Android phones into a worldwide earthquake detection system – delivering early warnings to millions of people across 98 countries and offering a bold new approach to public safety.
Using the built-in motion sensors in smartphones, the Android Earthquake Alerts System detects tremors in real time and sends alerts before damaging shaking arrives. Unlike traditional seismic networks, which rely on costly and sparsely located instruments, Google’s system harnesses the vast reach of everyday mobile devices to achieve a scale never before possible in seismology.
According to a new report published in Science, the system detected over 11,000 earthquakes during the three-year period, matching or even exceeding the accuracy of dedicated seismic tools. Instead of precision from a single source, the strength of the system lies in sheer volume: data from thousands of phones in a region is analyzed collectively to identify and triangulate quake activity.
“This isn’t about one phone detecting an earthquake perfectly,” explained Richard Allen, a seismologist from UC Berkeley and visiting faculty at Google. “It’s about millions of phones working together to see patterns that individual sensors might miss.”
The report marks the first in-depth review of the system’s performance since its quiet launch. In that time, the number of people receiving alerts has increased tenfold, extending protection to areas where official earthquake warning systems do not exist.
Still, the system faces challenges – especially when handling large, complex earthquakes. During the catastrophic quakes that struck Turkey in February 2023, the alerts sent underestimated the severity. Google’s internal review showed that upgraded algorithms could have doubled the reach and urgency of the alerts, potentially notifying up to 10 million people with stronger “TakeAction” messages.
“This kind of transparency is critical,” said Harold Tobin, a seismologist at the University of Washington. “If this technology is going to be used in public safety, civil authorities need to understand how it works and be able to evaluate it independently.”
That call for openness has fueled debate in the scientific community. While Google says it has been transparent about the Android-based system, questions remain about access to its proprietary algorithms and the use of user data.
Despite those concerns, many experts see promise. “Most countries don’t have any earthquake early-warning system at all,” noted Allen Husker, a seismologist at Caltech. “This could be a real game-changer – especially in low-resource regions.”
Google maintains that the system is designed to complement, not replace, official seismic monitoring efforts. And with the world’s earthquake risk increasing in some areas due to urban expansion and population growth, mobile-powered solutions like this could help close critical safety gaps.
“What this paper really does,” said Allen, “is show the scientific community that this system works – and it’s only getting better.”
