The average interval between major seismic events on the Hayward fault is about 140 years, plus or minus 50. USGS researchers say there’s about a 33% chance a magnitude 7 quake could take place on the fault in the next three decades, and there’s a slightly lower but still significant chance that two other faults that run through the Bay Area, the Paicines and San Andreas, could see some action.
One concern on the East Bay fault specifically is that it is made of a combination of locked and creeping lines. While the creeping ones move, normally causing some slight shaking, locked faults don’t. Instead, shaking on those could be foreshocks of a larger quake to come, UC Berkeley seismologist Roland Burgmann previously told KQED.
Whenever a quake — big or small — occurs, it’s a good time to check on earthquake kits and make sure to have the MyShake app downloaded.
The app, created by Berkeley’s Seismology Lab, gave Californians a few seconds’ notice before significant earthquakes last year and could make a real difference when a big one hits.
The farther from the epicenter, the longer the warning time you can usually get from the app, which sends out a notification instructing people to do what they’ve been taught since kindergarten but could forget in a panic: duck, cover and hold on.
“We’ve seen that for many earthquakes, particularly on the West Coast, in California, the people that are injured are injured by things falling on them because they’re trying to get to safety,” said Angie Lux, a project scientist for the Berkeley Seismology Lab’s earthquake early warning program. “It’s really hard to move during an earthquake.”