The quake was centered near Borrego Springs, 28 miles (45 kilometres) south of Palm Springs.
San Diego and Los Angeles County Sheriffs said there were no reports of injuries or structural damage.
The quake is related to the powerful Easter temblor that hit an isolated area near the U.S.-Mexico border, but it is not an aftershock, according to Seismologist Kate Hutton of the California Institute of Technology. Hutton said strain from the April quake transferred up to a different fault zone and triggered the quake.
Preliminary information indicates the quake was on the San Jacinto fault, the most seismically active fault in California and one of two that exhibited signs of increased pressure following the Mexico quake, according to a recent airborne analysis by the NASA Jet Propulsion Laboratory.
North County Coaster and Sprinter train service was halted for approximately 50 minutes to inspect the tracks for signs of earthquake related damage, but no damage was found, according to transit officials.
Nick Schuler, spokesman for Cal Fire said a rock approximately 4x5 feet fell off of a cliff onto Old Highway 80 near Buckman Springs Road, creating a 3x1 foot-deep hole in the concrete. Schuler said the rock had enough force to break two mature oak trees on the way down.
Hutton said residents should take today's quake as a warning to be prepared for temblors.
"The best way for people to look at this earthquake is that it's a drill,'' she said. "If this one had been the big one, what would I have done? Would I have been prepared? Would I have had my supplies, my plan and all that? So review everything, check your kit, because we can't predict earthquakes, we don't know when they're going to happen, so we have to be prepared all the time.''
