California residents can now download a smartphone app that can issue an earthquake warning moments before the ground begins shaking.

On Thursday, Oct. 17, the California Governor's Office of Emergency Services launched an early earthquake warning system that includes MyShake developed by the University of California, Berkeley. MyShake, which is now available through Google Play and Apple's App Store, will send an alert to areas that will be affected and potentially save lives.

"This app is at a place now where we're satisfied with the performance and the testing, which has been very well done, (so) that we think we're at a place where it's not perfect but we can keep people safe, and that's our ultimate threshold," said Brian Ferguson, the deputy director for crisis communication and public affairs at the Office of Emergency Services, to the SF Gate.

An Earthquake Warning Before The Ground Begins To Shake

The system still does not predict when an earthquake is about to occur. Instead, it relies on the numerous seismic stations across the state to detect the beginning of an earthquake and then send data to computers to calculate the location, magnitude, and intensity before an alert is distributed to users who are likely to feel the shaking.

Depending on the user's distance from the epicenter, the app might give a warning several seconds to a minute before the shaking begins.

"The system uses ground motion sensors from across the state to detect earthquakes before humans can feel them and will notify Californians so that they can 'drop, cover and hold on' in advance of an earthquake," said the Office of Emergency Services in a press release.

The system was put to the test earlier this week when the San Francisco Bay Area and Central California experienced a magnitude 4.5 quake and magnitude 4.7 quake respectively. According to Richard Allen, the director of UC Berkeley's Seismological Laboratory, the alerts were received with a median time of 2.1 seconds and 1.6 seconds respectively.

Loma Prieta Earthquake Anniversary

The statewide earthquake warning system's debut coincided with the 30th anniversary of the Loma Prieta earthquake that devastated the San Francisco Bay Area, killing 63 people. The earthquake caused the collapse of a section of the Bay Bridge and a double-decker freeway in Oakland.

Experts also anticipate "the big one" to hit any time.