Key facts
- Millions of people received mobile phone warnings for recent earthquakes in California, Venezuela, and Japan.
- Google's Android Earthquake Alerts system utilizes accelerometers in smartphones to detect seismic activity.
- National Early Earthquake Warning (EEW) systems are operational in countries including the U.S., Mexico, Japan, and Turkey.
- Japan's advanced S-Net system uses underwater sensors to provide longer warning times and faster tsunami alerts.
- Warning systems detect faster, less destructive P-waves to alert people before slower, more dangerous S-waves arrive.
- Warning times are typically only a few seconds and are shortest for those closest to the earthquake's epicenter.
Millions of people have received critical seconds of warning before experiencing earthquake shaking, thanks to mobile phone-based alert systems. Recent earthquakes in California, Venezuela, and Japan have highlighted the effectiveness of these technologies.
Google's Android Earthquake Alerts system, which leverages the accelerometers in individual smartphones, has provided warnings even in countries like Venezuela that lack national systems. These crowdsourced alerts can detect seismic waves and notify other phone users in the affected area.
Several nations, including the United States, Mexico, Japan, Turkey, Romania, China, Italy, and Taiwan, have developed their own Early Earthquake Warning (EEW) systems. Mexico launched the first public EEW in 1991. Following the devastating 2011 earthquake and tsunami, Japan significantly expanded its system, incorporating underwater sensors (S-Net) to monitor offshore seismic activity, which has improved warning times and tsunami alert speeds.
In the U.S., the USGS operates the ShakeAlert system for California, Oregon, and Washington, which distributes alerts through various channels, including the Wireless Emergency Alert system and apps like California's MyShake. These systems rely on detecting the fastest seismic waves, known as P-waves, to provide advance notice before the slower, more destructive S-waves arrive.
However, the effectiveness and reach of these systems can vary. People closest to the earthquake's epicenter typically receive the shortest warning times, and some individuals, particularly in rural areas or those without phones nearby, may not receive alerts at all. Experts emphasize the value of multiple alert systems as a backup.