Staff writers

SAN RAMON -- A magnitude-3.4 earthquake Wednesday morning was the largest among several small tremors over the past 24 hours to rattle the San Ramon area, according to the U.S. Geological Survey.

Wednesday's jolt hit at 9:31 a.m. along the Calaveras Fault and was centered near the Crow Canyon Country Club, near El Capitan Drive and Crow Canyon Road, at a depth of 6.8 miles, according to the USGS.

No one was injured, and there were no reports of damage.

The morning quake was followed by a microquake, measuring 1.4 at 12:28 p.m. Wednesday, and then by a magnitude-2.4 tremor at 12:47 p.m., the USGS reported.

Small but noticeable earthquakes have been rattling San Ramon Valley residents since Friday night when a 3.0 quake hit the area about 10 p.m. The remainder of the weekend didn't show any significant movement, but two smaller quakes measuring 2.9 and 2.4 shook the same area about 3:35 p.m. Tuesday, followed by a 2.1 tremor at 4:24 p.m., according to the USGS.

All told, San Ramon has logged 18 earthquakes in the past week, which isn't that unusual.

"The San Ramon Valley is one of the more highly seismic parts of the Bay Area with regard to the occurrence of small earthquakes. Since 1971, between Alamo and Dublin, there have been 148 earthquakes of magnitude 3.0-3.9 and 10 earthquakes of magnitude 4.0-4.4," said David P. Schwartz of the USGS.

By comparison, the city of San Jose had 22 earthquakes in the past seven days, but often the tremors are so small no one feels them. Schwartz said San Ramon's small earthquakes are typical of the earthquakes that have previously occurred in this region, and "there is no special significance to attach to them."

Still, he said people need to get those earthquake kits ready.

"The next large earthquake in the Bay Area is always just around the corner. We shouldn't be worried; we should be prepared," he said.