PASADENA, Calif. (AP) — Developers testing an earthquake early warning system for the West Coast say its automated alerts are ready to be used more broadly, but not for mass public notification.

U.S. Geological Survey official Doug Given told reporters Wednesday at California Institute of Technology that the ShakeAlert system has transitioned from a production prototype to operational mode.

The system built for California, Oregon and Washington detects an earthquake is occurring and send out alerts that may give warnings of few seconds to perhaps a minute before shaking arrives at locations away from the epicenter.

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