California unveiled the first statewide quake warning system in the United States on Thursday (local time), the state governor's office said.
Ground motion sensors from across the state will be used to detect earthquakes before humans can feel them, and notifications will be sent out to give Californians a second to tens of seconds to take precautions, according to a press release from the state's office of emergency services.
Alerts will be issued through a new cellphone app called MyShake as well as the more traditional wireless emergency system that sends out Amber Alerts.
In a test this week, alerts hit phones with a median time of 2.1 seconds in a magnitude 4.5 quake and 1.6 seconds in a 4.7 quake, said Richard Allen of UC Berkeley Seismological Laboratory.
The launch of the system falls on the 30th anniversary of the Loma Prieta earthquake, a 6.9 magnitude quake that hit the central coast of the state and killed 63 people.