Google has transformed motion sensors in more than 2 billion smartphones into a global earthquake early‑warning system, offering coverage comparable to traditional seismic stations, according to a study published in Science.
The Android Earthquake Alerts (AEA) system recorded more than 11,000 earthquakes between 2021 and 2024. It sent more than 1,200 alerts to users across 98 countries during that time. Researchers say this approach has expanded access to warnings tenfold — from 250 million people in 2019 to 2.5 billion today.
“Earthquakes are a constant threat to communities around the globe,” Google said in a statement. “What if we could give people a few precious seconds of warning before the shaking starts? Those seconds can be enough time to get off a ladder, move away from dangerous objects and take cover.”
Filling gaps in existing systems
Many countries, including China, Mexico, Japan, South Korea and the United States, already operate earthquake alert networks. These systems rely on seismic stations, which are expensive to build and maintain, leaving large parts of the world without coverage.
🚨 Google’s Earthquake Alert System now covers 98 countries, turning Android phones into mini seismometers to send life-saving early warnings. pic.twitter.com/07QSPgy8XL
— The Matrix (@thematrixloop) July 27, 2025
Google’s system addresses that gap by using accelerometers in Android smartphones and smartwatches to detect P‑waves, the fast tremors that precede more destructive S‑waves. The data allows the system to estimate an earthquake’s location and magnitude and send alerts to people in danger zones.
Overcoming technical hurdles
Building AEA required solving major challenges. Smartphone sensors are less precise than seismometers, so researchers relied on the vast number of Android devices to compensate for accuracy gaps. The team also adjusted for differences in device hardware, local geology and building structures to produce reliable alerts.
android earthquake alerts are actually cool in how they work
i assumed that they were just getting reporting data from the USGS or similar services and sending notifications out based on that data
but they are actually interpreting accelerometer data
each phone samples… pic.twitter.com/JaIa8UuJAE
— Phoenix𝕏 (@Xaraphim) July 26, 2025
The system is now active in countries including Greece, Turkey, Japan, Indonesia and the United States. By March 2024, it had issued 1,279 alerts. Surveys show that 85% of people who experienced an earthquake received a warning, with 36% alerted before shaking began, 28% during the quake and 23% after.
Limitations and updates
Only three alerts have been false — two caused by thunderstorms and one by an unrelated mass notification event. But large quakes remain difficult to assess. The system notably underestimated the magnitude of the February 2023 earthquakes in Turkey. Researchers attributed this to flaws in data collection and algorithms, which they have since revised.
Debate over private ownership
The system’s global reach has raised questions about a private company running life‑saving technology. Google maintains that AEA is designed to supplement, not replace, government‑operated networks.
“AEA demonstrates that globally distributed smartphones can be used to detect earthquakes and issue warnings at scale with an effectiveness comparable to established national systems,” researchers wrote.
“Large earthquakes remain the most important and challenging for all EEW [earthquake early-warning] systems, and the global implementation of AEA supports efforts to improve detection with rapid, large-scale data collection and feedback to algorithms..”
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