On Monday, an early warning system designed to provide people with critical seconds of warning before earthquakes fulfilled its promise. According to the " Guardian ", before the magnitude 6.2 earthquake occurred in northwest of California , the system issued a prompt sound through 500,000 mobile phones, the largest earthquake since the system called ShakeAlert was promoted throughout the state.
ShakeAlert obtains information from the sensor network of USGS (USGS). If the data from these sensors shows that there will be a large crust vibration in a certain area, people living there will be alerted via the MyShake app (if they have downloaded it), or via the wireless emergency alert system on their phones. Alerts can also be issued to Android users through collaboration between Google, the U.S. Geological Survey and the California Office of Emergency Affairs.
The epicenter of Monday's earthquake is located on the coast of a small town called Petrolia, about 45 miles from the nearest population center Eureka. Robert de Groot, ShakeAlert coordinator for the US Geological Survey, said people reported an alarm was received about 10 seconds before the earthquake began, making the first major earthquake handled by the system a successful proof of concept. The earthquake caused no major damage to the area, nor did it cause any casualties. The
ShakeAlert system was first launched in Los Angeles in 2018 and then expanded across California in 2019. When a magnitude 6.4 earthquake occurred 150 miles outside the city of Los Angeles, the system was in place, but no alarm was issued because the city's expected shaking was not strong enough to cross the application's threshold. Users complained that even if they felt the shaking, they didn’t receive an alert, so the app’s developers lowered their thresholds before they were launched statewide.
Now, the scientists behind ShakeAlert can use information from the recent earthquake to improve the system again for the next time. "We really have to learn the most from real earthquakes. This gives us the opportunity to use the system and learn how to better remind people," de Groot told The Guardian.
