The nation's first statewide quake warning system coincides with the 30th anniversary of the Loma Prieta earthquake that ravaged the San Francisco Bay area on Oct. 17, 1989, as well as the annual Great Shakeout safety drill.

Warnings produced by the ShakeAlert system will be pushed through two delivery systems: a cellphone app called MyShake and the same wireless notification system that issues Amber Alerts, meaning people may receive both notifications.

Gov. Gavin Newsom, flanked by some of the state's preeminent seismologists, announced the systems at a press conference, Thursday, noting the U.S. Geological Survey's calculation that California has a 99.7% chance of being struck by at least a 6.7 magnitude earthquake within the next 30 years.

“It’s a rather jaw-dropping prediction,” Newsom said. “Particularly from experts that are cautious in making those types of predictions. That’s the reality we live in. ... The price of admission to live here is preparation."

At the same time he celebrated the launch of the technology, he took pains to qualify expectations for the app.

“We are confident that this app will do justice to what we are promoting; perfect, however, is not on the agenda,” he said. “We recognize this is a work in progress and we will have to iterate over the next few years."

Available for Download

Despite that warning, Brian Ferguson, deputy director for crisis communication at the Office of Emergency Services, said the 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."

Developed at the University of California, Berkeley, MyShake is available for download to IOS users through iTunes and through GooglePlay stores for Android phones.

"The alerts will only go to people that are going to feel shaking," said Richard Allen, director of the UC Berkeley Seismological Laboratory.

The thresholds for an alert are an earthquake of magnitude 4.5 and shaking intensity level 3.

"Intensity 1 is you don't feel it; intensity 2 is some people may feel it; intensity 3 is many people do feel it," Allen said.

The ShakeAlert system is being developed by the U.S. Geological Survey and partners for the West Coast states. It is most complete in California.