Quake swarm rolls on as magnitude-3.2 shakes San Ramon Valley

A magnitude-3.2 earthquake shook the East Bay the morning of Friday, Oct. 23, 2015, one of more than 200 small quakes to hit the area over the last couple weeks. A magnitude-3.2 earthquake shook the East Bay the morning of Friday, Oct. 23, 2015, one of more than 200 small quakes to hit the area over the last couple weeks. Photo: Courtesy, U.S. Geological Survey Photo: Courtesy, U.S. Geological Survey Image 1 of / 24 Caption Close Quake swarm rolls on as magnitude-3.2 shakes San Ramon Valley 1 / 24 Back to Gallery

The swarm of small earthquakes that have been rumbling through the East Bay continued Friday morning as a magnitude-3.2 quake hit the San Ramon Valley area — one of more than 200 shakers that have struck since Oct. 15.

Friday morning’s temblor, which hit at 6:48 a.m. on the Calaveras Fault and was centered just northeast of San Ramon at a depth of about five miles, was one of the stronger quakes to jolt the area — most of which have been between magnitude-0.8 and 2.0 — but not large enough to cause any significant damage.

Video: San Ramon Earthquake Swarm Community Reactions

Still, it was felt as far north as Pittsburg and as far south to Dublin, according to the U.S. Geological Survey.

Seismologists say residents of the area have little to worry about. The Calaveras Fault is simply releasing tension, and the chance for a big quake — one stronger than magnitude 6.7 — is low, about 7 percent within the next 30 years.

“Little earthquakes don’t necessarily influence larger earthquakes,” said Sarah Minson, a seismologist at the geological survey. “This really isn’t unusual, especially for that area.”

A swarm of 120 small quakes shook the same area back in 2003.

Kale Williams is a San Francisco Chronicle staff writer. E-mail: kwilliams@sfchronicle.com Twitter: @sfkale