- California town hit by more than 100 minor earthquakes
- Earthquake swarms not uncommon for the area, experts say
Caltech seismologist Lucy Jones said earthquake "swarms" aren't unexpected around Brawley -- there also was a swarm in 2012 -- because the fault-riddled region called the Brawley Seismic Zone lies between the large San Andreas Fault and the Imperial Fault.
More than 100 earthquakes have hit the region this weekend, but most are too weak, under 2.5 magnitude, to be noticed by people, said Donyelle Davis, spokeswoman for the United States Geological Survey.
Weak quakes can trigger a bigger, more dangerous quake, but Brawley, a city of about 25,000 people near the Mexican border, is too far from the San Andreas Fault
for that to be much of a risk, Davis said.
"This area may have produced the most earthquakes in the entire state of California, but they are small," Jones said. "If they happened a mile away we would be concerned, but these quakes are about 30 miles from the San Andreas Fault."
Since Saturday at least 24 quakes have been 2.5 to 3.9 magnitude, according to the Geological Survey. Earthquakes of 3.9 magnitude or less generally create little or no damage
They are common in California. As of noon Sunday, the state had had 191 earthquakes in the past 24 hours and 7,707 in the past 365 days, with the largest measuring 6.5 in Ferndale, according to the website earthquaketracker.com.
Catastrophic earthquakes seem to strike along the southern San Andreas Fault about once every 150 years
, the Geological Survey said, citing studies examining the past 1,400 years. The last time an enormous temblor on the fault struck Southern California was in 1857.