Get a heads up BEFORE the shaking reaches you

Earthquake Warning California is a program to alert people before shaking reaches them. It is the final step in the ShakeAlert® system that detects, analyzes, and disseminates information to give you a little time to DROP, COVER and HOLD ON and safely ride out the strongest shaking. 

ShakeAlert® and Earthquake Warning California is a partnership of the USGS, Berkeley Seismology Lab, Caltech, California Office of Emergency Services and other universities and agencies.

a graphic of seismic stations, connecting to a brain, connecting to cellphones

1. Detection

Seismic stations DETECT earthquakes. Seismic waves travel several miles every second. As soon as waves reach four or more stations, the PROCESSING Center is triggered.

2. Processing

The PROCESSING Center analyzes the seismic signals and estimates the location, magnitude and the area of strong shaking. If the magnitude and shaking strength are above a certain threshold, a ShakeAlert message is issued and sent to DELIVERY.

3. Delivery

The ShakeAlert messages are sent to YOU through the MyShake App. All Californians can download MyShake for iPhones or Android systems from your App store free of cost.