California

Earthquake Early Warning: What to Know About ShakeAlert LA

ShakeAlert LA warnings are issued for all quakes, including aftershocks, of magnitude-5.0 or greater in Los Angeles County

What to Know

  • The ShakeAlert is designed to provide at least a few seconds of warning before the shaking starts
  • The alert includes a sound and message that indicates the anticipated intensity level
  • ShakeAlert warnings are issued for all quakes, including aftershocks, of magnitude-5.0 or greater

The nation's first publicly available earthquake early warning mobile app has been launched as part of a pilot program designed to give LA County residents a few seconds of warning before the shaking.

Once the ShakeAlert LA app is downloaded, users are asked to enable notifications. ShakeAlert warnings are issued for all quakes, including aftershocks, of magnitude-5.0 or greater. The alert includes a sound and message that indicates the anticipated intensity level.

The early warning function only works in Los Angeles County. The app does not need to be open, but users must set the phone's location services to "Always On."

ShakeAlert LA also has resources to help prepare for an earthquake.

It's part of the early warning system being built for California, Oregon and Washington detects that an earthquake is occurring, quickly analyzes the data and sends out alerts that may give warnings of several seconds to a minute before strong shaking arrives at locations away from the epicenter. A few seconds is enough time to scramble for protection, slow trains, halt industrial processes, trigger back-up power generators and pause surgeries at hospitals. 

Pilot programs involving select users have been underway for several years.

A new generation of ShakeAlert software was deployed in September, including improvements in reducing false and missed alerts. False alerts typically have occurred when a large quake elsewhere in the world is detected by a sensor and is mistaken for a local earthquake. 

There's still work to do. The sensor network is only about 50 percent of the target size. Funding has been secured to complete the network in California in the next two years.

Copyright AP - Associated Press
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