California earthquake warning app sends 1st public alert

Exactly two months to the day after the University of California, Berkeley released the free earthquake warning app to the public, it got its first real-world and real-time test. 

The MyShake app worked "perfectly" for the relatively moderate quake. The app is designed to send out earthquake warnings to those within shaking distance of magnitude 4.5 tremblor or greater.  

The app sends out a warning that reads, "Earthquake! Earthquake! Expect shaking. Drop. Cover. Hold on." 

California Governor Gavin Newsom in October promised to launch the nation's first statewide Earthquake Early Warning System funded by the California Office of Emergency Services (Cal OES). 

"The further away you are from the epicenter, the more warning time you can receive," said Cal OES Director Mark Ghilarducci. 

"Meaning that you may have a few seconds, perhaps ten, twenty seconds worth of warning time," University of California, Berkeley Seismic Lab Director Richard Allen explained.

The app has already been download more than a quarter-million times.

More than 40 people received a warning Tuesday when a 4.3 magnitude quake struck in a very remote area under the Central Coast mountains. 

It sent the warning because the initial reading was magnitude 4.8.

UC Berkeley seismic scientist Angela Chung was instrumental in developing the app. "Pretty much every time there's a major event, we learn something new from our system. So, we're continuing to update our system as we get these new earthquakes as things happen and we're making the system better every time," said Chung. 

Even with very short notice, people who get the warning are less traumatized by the shaking. Chung said, "It definitely does help people to prepare mentally for the earthquake, even it's just a couple of seconds."