We examine the complex series of fault ruptures and earthquakes that struck near Ridgecrest in Southern California over the July 4 weekend of 2019. A 6.4 magnitude temblor on the evening of July 4 was followed by in even bigger magnitude 7.1 event just over 24 hours later that may have been triggered in a process called cross faulting during the earlier quake.

Two small quakes shook an area about 10 miles north of Chico Tuesday morning, but it’s likely you did not feel them. The USGS says a 3.0 shaker hit at 8:01 in the foothills north of Pine Creek in Tehama County. The second quake hit just three minutes later in Butte County, south of Pine Creek. Both were at a depth of 10.5 miles.

Meanwhile a 4.3 quake shook the north coast Tuesday morning 30 miles west south west of Eureka. That quake struck at 3:17. There are no reports of damage or injuries from any of the quakes. 

California Geological Survey


The chances of a very strong earthquake rattling California is higher than previously thought, and more comprehensive studies suggest inland Northern California is hardly immune from sudden seismic disturbances.

The number of identified faults in California has risen from 15 in 1988 to 350 today. The chance of a quake 6.7 or greater — the strength of the destructive 1994 Northridge quake — was cut to once every 6.3 years. Meanwhile, the chance of a potentially cataclysmic magnitude 8 or greater within 30 years was revised upward to 7 percent.