A swarm of at least six earthquakes reaching up to magnitude 2.9 rattled San Ramon near San Francisco, the U.S. Geological Survey reports. The other quakes in the Saturday, Dec. 13, swarm ranged from magnitude 1.3 to 2.3, according to the USGS.

San Ramon has been hit by multiple quakes over the past four days, including magnitudes 2.9, 2.3, and 2.2 on December 13, a 2.8-magnitude quake on December 14 and 2.4 and 2.1 on December 15. There were dozens of other smaller tremors. Read More | San Jose earthquake: Massive jolt in California; tremors in Hollister, Salinas and Dublin

California's seismic risk is increasing with supershear earthquakes, which are faster and more destructive than typical earthquakes.

On Monday morning, around 30 minor earthquakes erupted in a swarm near the Geysers geothermal field south of Clear Lake. The day before, seven quakes rattled Sonoma County, including a 4.0 quake. The recent uptick isn’t out of the ordinary, according to U.S. Geological Survey seismologist Susan Hough.

Major quakes in Japan and Alaska along with a spate of smaller earthquakes in California this fall make folks ask, is the Big One near?

Residents in Nevada woke up to a shocking 5.9 magnitude earthquake alert, but after the panic settled, the whole thing turned out to be a fake quake alert sent by USGS.

A shake alert went out over the U.S. Geological Survey's early warning system on Dec. 4, warning that a 5.9 earthquake near Carson City in western Nevada could produce heavy shaking in the region. But moments later, the survey announced the alert, which was sent to people as far west as San Francisco, was a false alarm.

A rare, ultra-long earthquake in Myanmar revealed that mature faults can deliver their full force directly to the surface. The discovery could mean stronger shaking near faults like California’s San Andreas than current models predict.

VENTURA COUNTY, CA - A 3.3 magnitude quake was reported close to Ojai Tuesday morning, according to the U.S. Geological Survey.