Last Updated on April 15, 2025 by The HD Post Staff
CALIFORNIA – The Governor’s Office of Emergency Services (Cal OES) announced that its Earthquake Early Warning System provided advance notification to millions of Southern Californians on April 14 before a 5.2 magnitude earthquake struck.
According to Cal OES, at 10:08 a.m., an earthquake, near Julian in San Diego County, was felt across large portions of Southern California.
Almost 700,000 phones in the affected area received notifications through the state’s MyShake app. Millions more received these notifications through wireless emergency alerts and Google alerts.
“Warning Californians before earthquakes strike can save lives,” said Cal OES Director Nancy Ward. “The MyShake app is doing what it is designed to do, and we encourage all Californians to download it today”.
Sensors detect P-waves before more destructive S-waves arrive
Cal OES said before shaking is felt, ShakeAlert, an automated program operated by the United States Geological Survey (USGS) and others, analyzes data from seismic networks.
“In an earthquake, a rupturing fault sends out two different types of waves. The fast-moving P-wave is first to arrive, but the damage is caused by the slower S-waves and surface waves,” said a statement on the Cal OES site.
Sensors detect the P-wave and immediately transmit data to an earthquake alert center. The location and size of the quake are determined and a message is then transmitted to users.
Photo credit: Earthquake Warning CaliforniaCal OES said there are limitations to the system.
The alert cannot come before the earthquake starts and people may receive an alert before, during, or after shaking arrives at their locations.
27,000 new MyShake app downloads after earthquake
Following Monday’s earthquake, Cal OES said there were more than 27,000 new downloads of the MyShake App.
The majority of smartphones with updated operating systems automatically receive earthquake alerts.
Other ways Californians can make sure they get Earthquake Early Warning alerts include:
- Downloading the free MyShake App;
- Ensuring Wireless Emergency Alerts (WEAs) are enabled on a user’s smartphone.
To learn more about earthquake preparedness and download the MyShake app, visit: www.earthquake.ca.gov.
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