UC Berkeley video by Roxanne Macasdjian and Stephen McNally.
The mobile phone app, MyShake, can provide a few seconds of warning before being shaken by a nearby earthquake - enough time to drop, cover and hold to prevent injury.
"Nothing can replace a plan for earthquakes and other emergencies to families," Newsom said. "And we know that the 'Big One' may be around the corner. I encourage every Californian to download this app and make sure your family is prepared for the earthquake."
Newsom announced roll-outs with the Governor's Office of Emergency Services (Cal OES), UC Berkeley, the United States Geological Survey (USGS) and several state and local political leaders.
The announcement was made on the 30th anniversary of the 1989 Loma Prieta earthquake, a magnitude 6.9 earthquake that damaged or collapsed buildings, overpasses and bridges in the Bay Area from Santa Cruz, killing 63 people and injuring 3,754 people.
Early warning, not prediction
The ShakeAlert system does not predict an earthquake, but rather provides a warning that an earthquake has been detected nearby and warns recipients that they are likely to feel tremors. It detects the first waves of an earthquake, called P waves, from an earthquake that travels faster than much more damaging waves. The farther away you are from the epicenter, the longer the delay between P and S waves and the more advance warning you get.