HOLLISTER (CBS SF) -- A swarm of more than 20 aftershocks along the San Andreas Fault system rattled an area east of Monterey Bay Friday morning.
The largest quake measuring magnitude 4.1 struck just before 6 a.m. about 12 miles from Hollister, rattling nerves but causing no major damage, authorities said.
According to the U.S. Geological Survey, the 4.1 quake hit at 5:58 a.m. PDT 12 miles southwest of the small community of Tres Pinos. It was followed by quakes measuring 3.6, 3.2, 3.0, 3.2, 3.6, 2.9, 2.7 and 3.4.
Nearly a dozen aftershocks would rattle the region for the next half hour before finally tapering off.
"It's not the pattern for a cluster. There was one large earthquake this morning. And then there's been a series of smaller earthquakes that followed," said USGS Geophysicist Brian Kilgore
The USGS said the quakes were most strongly felt in nearby Hollister followed by Salinas, Gonzales, Monterey, Carmel Valley and Santa Cruz.
Authorities did not report any damage.
Matzuma Li, who lives in the Central Valley took to Twitter, saying the jolt awoke she and her cats.
"Nice way to start the day... A pleasant 4.0 to shake the cats through the roof at 6am," she tweeted.
Kristina Pinto took to Facebook hearing her home rattle during the swarm.
"Felt last 2 after 6am. Was awake. I'm like I'm hearing moving and cracking."
Joni Lester-Hook posted: "Still shaky off and on here."
The USGS emphasizes that everyone should have a plan about what they will do as an individual and member of a family in the event of a major earthquake. That also involves keeping stockpiles of food and water.
for more features.