Los Angeles officials are urging residents to download a new earthquake detection app that's designed to give users a heads up before the next "big one" hits.
The ShakeAlertLA app is connected to the US Geological Survey's network of early warning sensors.
Users in the Los Angeles County area will receive a push alert on their phone when the system senses an earthquake of magnitude 5.0 or greater.
The alert would read "Earthquake! Earthquake! Expect strong shaking Drop, cover and hold on. Protect yourself now!"
The USGS says the warnings could go out seconds, or even tens of seconds, before people start to feel the shaking.
"It will give you -- depending on how far away, of course, the earthquake is -- precious seconds of notice to be able to get some place safe, to alert your co-workers, your family," Los Angeles Mayor Eric Garcetti said on Facebook Live. He said that in the future it would be linked to elevators and metro trains so they can stop before the earthquake hits.
Los Angeles is the first US city to make the app available to the public, but the US Geological Survey plans to deliver it to the entire West Coast once the pilot project is completed.
"We cannot predict earthquakes, but we can tell you an earthquake has started and it's on its way to you," California Institute of Technology seismologist Tom Heaton told CNN affiliate KABC. Heaton helped design the system.
Garcetti said the system is open sourced and they are working to help other cities set up alert systems of their own.
The app is a collaboration between L.A., the US Geological Survey, The Annenberg Foundation and AT&T, CNN's parent company. It's available in English and Spanish in the Apple and Google Play stores.