[amf12]

Android also has a "detection" feature in non ShakeAlert locations. Android phones' accelerometer is used to detect earthquakes and warn other phones in the area: https://crisisresponse.google/android-alerts/

Android phones' accelerometer also detected the tremors: https://twitter.com/davey_burke/status/1585148438844694528

It's a pretty cool technical problem to solve while optimizing latency.