Frequently Asked Questions

What is EEW?

The California Earthquake Early Warning System marries a smartphone application with traditional alert and warning delivery methods such as Wireless Emergency Alerts (WEA). The system use ground motion sensors from across the state to detect earthquakes before humans can feel them and notifies you in real time.

How much advance notice will I get?

That will depend how far you are from the origin of the earthquake. For example during the Loma Prieta Earthquake those attending the World Series Game at Candlestick Park would have received approximately 20 seconds of advance notice and Marina District would have received approximately 22 seconds of advance notice.

Who will receive these notifications?

You will automatically receive Wireless Emergency Alerts on your WEA-enabled phone. However, the “MyShake” application from the App store or Google Play will allow people to receive alerts when they don’t have cell phone services but do have WiFi and thus far has shown to be faster than other alert delivery methods. 

WEA alerts will be issued more significant earthquakes (magnitude 5 or greater) and the “MyShake” app is designed to alert the public to a wider range intensities (magnitude 4.5 or greater).

OES encourages all Californians to download the application so that they can have redundancy and receive alerts from both sources.

Is there an area that will not receive advance notification?

Those very near the origin of the earthquake may not receive an alert BEFORE they feel shaking. The farther users are away from the origin the more advance notice they will receive.

Who issues the alert?

The new system automatically generates alerts through the California Integrated Seismic Network.

What can I do with a few seconds notice?

Even a few seconds of advance notice can be lifesaving. At a minimum these rapid response alerts will allow users to drop, cover and hold on during an earthquake.

This is why the state encourages all users to update their phone setting to allow alerts.

Who is involved in the CISN?

As mentioned above, CISN is a consortium of geological experts from across the western united states including: Cal OES, USGS, CGS, UC Berkeley, Cal Tech, Lawrence Livermore Lab, DWR, UC Santa Barbara, UC San Diego, University of Washington, University of Oregon and University of Nevada Reno among other contributing organizations.

How can I get the app?

It is available for free in the Apple App Store and Google Play.

What if I don’t have a smart phone, can’t use one or and/or am part of a vulnerable group?

OES is collaborating with organizations to develop products to deliver alerts to communities with access and functional needs.

I live in an area where there aren’t earthquakes. Why do I need this?

There is earthquake risk throughout the state. If earthquakes are large enough, the energy spreads far wider than most imagine. For instance, when the Coalinga earthquake occurred in 1983, it was a magnitude 6.2 event and had a shake intensity of VII (severe). Shaking was felt from Los Angeles to Lassen County as well as in Nevada. 

On top of known high earthquake hazard zones, earthquake occur on previously unknown faults, in fact that was the case for both the Ridgecrest and Northridge Earthquakes. 

There is also the need to be prepared as people travel throughout the state. 

What will a WEA alert look like, on my phone? Will my phone make the same sounds as when it is notifying me of a missing child?

EEW alerts will look, and sound like other emergency alerts. The message will say “Earthquake, earthquake. Expect Shaking. Drop Cover and Hold On. Take protective actions.” 

What earthquake magnitude is necessary to receive a notification?

See above, The system will send geo-targeted alerts based on shake intensity in your area. Shake intensity is derived from a variety of factors including depth, geology and earthquake magnitude.

What should I do once I receive the alert or feel an earthquake?

Drop, cover and hold on OR for those in wheel chairs “lock, cover and hold on.”

What are the other benefits of EEW?

In addition to providing rapid notification through WEA and the application, the system allows automatic actions like: slowing down trains, opening fire station doors, alerting medical personnel to halt medical procedures and more.

Are other Countries already using this technology?

Yes. Japan, Taiwan, South Korea, Mexico, Italy, China among others use similar early warning systems. California is the first state in the nation to provide this sort of rapid alerting.

Is it possible that I will receive a false alert or not receive an alert at all before I feel an earthquake?

This is new technology that will be continually refined. All of the earthquake data gathered following launch will allow the system to be improved in the months and years to come.

Will the application collect my data?

The application will store high level location data at the time of an earthquake but no personally identifiable information will be collected.

Will the application make my cell phone’s battery drain faster?

As is the case, with any application running in the background of your phone, battery life will be affected. The Android version does has a special “battery saver” mode that can be enabled.

Are there cyber security concerns with the system?

The Office of Emergency Services has worked state cyber security experts and outside industry specialists to ensure the app is safe to use.

Will you be testing the application?

Users may receive occasional test messages. These messages will used to test and improve the functionality of the application and do not require any action on behalf of the user.

Will the application work outside the state?

Currently the live alerts are limited just to California. It is possible that users just outside state’s borders may receive notifications