Officials in California will unveil the nation's first statewide earthquake early warning system on Thursday.
The California Earthquake Early Warning System utilizes a smartphone app as well as traditional alert and warning delivery methods, such as Wireless Emergency Alerts.
"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 California Governor's Office of Emergency Services (Cal OES) in a statement.
Cal OES, UC Berkeley, United States Geological Survey (USGS) and California state Sen. Jerry Hill, D-San Mateo, will take part in the launch event, which is scheduled for 2 p.m. ET at Gateway Park in Oakland. The launch coincides with California’s annual Great Shakeout earthquake safety drill.
Thursday also marks the 30th anniversary of the deadly Loma Prieta earthquake, which ravaged the San Francisco Bay area on Oct. 17, 1989. The 7.1 magnitude 'quake killed 63 people and at the time, caused $6 billion in damage.
The new system integrates the existing ShakeAlert earthquake early warning system, which sends alerts before 'quakes hit. Warnings produced by the ShakeAlert system will be pushed through two delivery systems: the MyShake cellphone app and the same wireless notification system that issues Amber Alerts, meaning people may receive both notifications.
"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, deputy director for crisis communication and public affairs at the Office of Emergency Services.
The state earthquake app is available for download to iOS users through the App Store and through Google Play 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 MyShake system maintains a database of which cellphones are in 10-kilometer-by-10-kilometer (6.2-mile-by-6.2-mile) cell grids and pushes the alerts to phones in zones where at least level 3 shaking will occur, so receiving an alert is not based on which tower the phone is communicating with, Allen said.
The Wireless Emergency Alerts system, known as WEA, operates slightly differently.
WEA creates polygons that include cellphone towers, said Ryan Arba, chief of the seismic hazards branch of the Office of Emergency Services.
The Associated Press contributed to this article. Follow James Rogers on Twitter @jamesjrogers