A global Android smartphone-based earthquake detection and early warning system can detect seismic activity in real time and deliver life-saving alerts with effectiveness rivaling that of traditional seismic networks, according to a new study. Despite our ability to predict where they are likely to occur, earthquakes continue to pose a serious threat to communities worldwide. Large-scale events can result in widespread loss of life and injury. These risks underscore the urgent need for protective measures including earthquake early-warning (EEW) systems, which can offer advance notice and save lives. These systems are often built on permanent seismic networks. However, many earthquake-prone countries lack this critical infrastructure. The widespread use of smartphones globally has created a powerful platform for sensing and delivering earthquake alerts. While the sensors in smartphones are not as precise as those in traditional seismic stations, they are still capable of detecting ground shaking during significant earthquakes.

Here, Richard Allen and colleagues present the performance of a global earthquake detection and alert system that harnesses the existing network of Android smartphones. The Android Earthquake Alerts (AEA) system leverages the phones’ sensors to detect seismic activity and deliver early-warning alerts to users before dangerous shaking begins. According to the authors, this capability is embedded by default in Android phones, which make up about 70% of smartphones globally. Over its first three years of operation (2021-2024), the AEA system detected an average of 312 earthquakes per month, spanning magnitudes from M 1.9 to a maximum of M 7.8 across 98 countries. For earthquakes measuring M 4.5 or higher, alerts were issued to users, amounting to roughly 60 events and 18 million alerts per month. To assess the effectiveness and user response to these alerts, the authors highlight how the system collects voluntary feedback through user surveys. AES user feedback indicates that 85% of recipients experienced shaking, with 36% receiving the alert before, 28% during, and 23% after the onset of ground motion. “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,” write Allen et al. “Large earthquakes remain the most important and challenging for all EEW systems, and the global implementation of AEA supports efforts to improve detection with rapid, large-scale data collection and feedback to algorithms.”