In the last week, a three mile stretch of the fault around Monterey County, just south of San Jose, was smashed by 134 earthquakes.
The largest was registered at 4.6 on the Richter scale – strong enough to be felt 90 miles away in San Francisco – at 11.31AM local time on Last Monday.
Of the rest, 17 were of a magnitude 2.5 or higher, and six above 3.0.
Now experts have warned the worst may not be over yet and believe more tremors are on the way.
Ole Kaven, a US Geological Survey (USGS) seismologist, said: “This one has been a quite productive aftershock sequence.
“We suspect there will be aftershocks in the two to three [magnitude] range for at least a few more weeks.”
“It’s a reminder that we live in earthquake country, I suppose.”
Steve Anderson, a meteorologist from the National Weather Service office, felt the biggest earthquake in Monterey.
He said: “It lasted about five seconds.
“There was a little bump and then a rolling motion. One of my colleagues said it made him feel seasick.”
Experts have previously warned small earthquakes along the San Andreas Fault could lead to a larger one in the future.
Thomas Jordan, head of the Southern California Earthquake Center, told the Los Angeles Times last year: “Any time there is significant seismic activity in the vicinity of the San Andreas Fault, we seismologists get nervous.
“Because we recognise that the probability of having a large earthquake goes up.”
California sits on top of the potentially catastrophic fault, a chasm between two massive plates of the Earth’s crust that extends hundreds of miles across the country.
Also, beneath California, the Pacific and North American tectonic plates are moving northward – although the former is moving quicker leading to a build up of tension.
A powerful earthquake in 1857 released some of this pressure, but much more still exists, and Robert Graves, a research geophysicist at USGS, suggests the Big One could be overdue by 10 years.
He told Raw Story: “The San Andreas fault in southern California last had a major quake in 1857 (magnitude 7.9).
“Studies that have dated previous major offsets along the fault trace show that there have been about 10 major quakes over the past 1,000-2,000 years… the average time between these quakes is about 100-150 years.”