California earthquake puts early warning system to the test

By SOPHIE AUSTIN
Associated Press/Report for America

SACRAMENTO, Calif. (AP) — An earthquake warning system operated by the U.S. Geological Survey warned 3 million people about a quake that jolted Northern California’s coast. The temblor Tuesday was the biggest test yet to the ShakeAlert system since it launched in 2019. Various phone apps use ShakeAlert data to notify users. But some people say they received an alert while the earthquake was ongoing. A glitch in one app awoke people in San Diego who were more than 600 miles from the shaking. The system represents one of a few earthquake warning technologies run by governments throughout the world.