Swarm of quakes continues to circle East Bay

SAN RAMON, Calif. (KGO) -- More than 251 earthquakes have hit the East Bay in the past week and seismologists are now looking for connections between a couple of critical East Bay faults.

Scientists call it a swarm, not of bees or hornets, but a swarm of earthquakes and many are centered in San Ramon.

At the local Starbucks, the iced-tea is shaken and so are the customers.

"Kind of popped up, thought something was happening downstairs and realized it was an earthquake," said San Ramon resident Tiffiney Ward.

In the last week, hundreds of small earthquakes, and a few not-so-small, have hit in along the Calaveras Fault centered in San Ramon. Seismologists at the University of California, Berkeley say these are not foreshocks or aftershocks for a bigger quake. They call it a swarm.

"In the case of a swarm, there's small earthquakes happening," said Peggy Hellweg, a UC Berkeley seismologist.

They could've picked a better name, but the thing about swarms is they can last for a while.

"The last time there was a swarm like this it went on for 31 days," Hellweg said.

Seismologists say a swarm does not usually precede a major quake. If the big one did hit in San Ramon, researchers in Berkeley might have cause to worry.

"We always thought of them as being separate faults, but what we learned is maybe they're not as separate as we think," Hellweg said. "And maybe if there's a big earthquake on the Calaveras it could bleed over into the Hayward fault and cause us concern over here."

"It makes me a little nervous, I think I need to start buying some earthquake supplies, getting a little emergency kit for the kids," Ward added.

That's how experts want people to respond, to not be shaken but stirred to action.

"You can't lose sleep over it, otherwise you have to move," San Ramon resident Peter Weiner said.