On Wednesday, California officials announced the launch of the nation’s first statewide early warning system for earthquakes.
The system, called ShakeAlert, will officially debut on Thursday, according to the California Governor’s Office of Emergency Services. The date marks the 30th anniversary of the deadly Loma Prieta earthquake in San Francisco, which killed 63 people, injured nearly 4,000 and left thousands more homeless.
The system will use sensors to detect earthquakes before people feel them, and notify potentially affected residents through a smartphone app called MyShake.
While scientists cannot predict the timing or location of earthquakes, the system is meant to detect an earthquake once it starts and warn affected residents before stronger shaking hits. The warning time would be a matter of seconds, according to the ShakeAlert website.
Officials advised residents who get warnings to ”drop, cover and hold on.” Alerts will only go out if the quake is of a high enough magnitude and would be likely to produce significant damage.
Several earthquakes shook California in recent days, including a 4.5 magnitude quake in the San Francisco Bay Area on Monday. (There was no significant damage reported.)
There are limits to the warning system, its website warns, noting that “no system is perfect.” It specifies that “significant” warning would be hard at the epicenter of a quake, and it could fail to send warnings or send some for earthquakes that are too small to cause any real damage.
Researchers have been developing the early warning system for the state for more than a decade. Los Angeles began using a related app earlier this year but did not send out alerts after big quakes in the area over the summer, as the estimated damage wasn’t high enough to meet the warning threshold.
Two strong quakes shook Southern California in July: A 6.4 magnitude earthquake on the Fourth of July near Ridgecrest, followed by a 7.1 magnitude event in the same area the next day. The shakes were felt by millions, including people in Los Angeles and Las Vegas, but caused minor damage.
Californians are always on alert for quakes and are particularly wary of the notorious “big one” predicted to one day hit the Los Angeles or San Francisco Bay area.
“It is a certainty that California will experience large and potentially damaging earthquakes in the coming years,” Robert Graves, a research geophysicist at the USGS, told HuffPost in July, noting that there are multiple active faults in California along which quakes can occur.
If you live in California, prepare before the next earthquake hits by building an emergency kit and practicing how to “drop, cover and hold on.”