"Shaking in 5 seconds!" A Voluntary Smartphone-based Earthquake Early Warning System

TL;DR

This paper presents a novel smartphone-based earthquake early warning system that leverages user devices as motion detectors, demonstrating its effectiveness across multiple countries and analyzing user reactions to warnings.

Contribution

It introduces the first purely smartphone-based earthquake warning system operating internationally, bypassing costly infrastructure and studying user understanding and responses.

Findings

Warnings issued in multiple countries for damaging tremors

Users understand warnings and find them useful for psychological preparedness

Only a small fraction of users take protective actions after warnings

Abstract

Public earthquake early warning systems have the potential to reduce individual risk by warning people of an incoming tremor but their development has been hampered by costly infrastructure. Furthermore, users' understanding of such a service and their reactions to warnings remains poorly studied. The smartphone app of the Earthquake Network initiative turns users' smartphones into motion detectors and provides the first example of purely smartphone-based earthquake early warnings, without the need for dedicated seismic station infrastructure and operating in multiple countries. We demonstrate here that early warnings have been emitted in multiple countries even for damaging shaking levels and so this offers an alternative in the many regions unlikely to be covered by conventional early warning systems in the foreseeable future. We also show that although warnings are understood and appreciated by users, notably to get psychologically prepared, only a fraction take protective actions such as "drop, cover and hold".