4.9 magnitude earthquake shakes Southern California

A 4.9 magnitude earthquake struck roughly 14 miles east, northeast of Barstow Monday at 1 p.m., according to according to the United States Geological Survey. 

Preliminary reports listed the magnitude at 4.7. The epicenter, in the Calico Mountains, is a sparsely populated area. Aftershocks, including a 3.5 and a 2.7, were felt in the same area within minutes of the first quake. 

The shaking was felt as far west as the Los Angeles area, including Burbank, Pasadena and Studio City. There were no immediate reports of damage or injuries in the LA area. The Los Angeles Fire Department said it has not been placed on earthquake mode.  

Dr. Lucy Jones, seismologist, commented on X that earthquakes of this size have been seen "many times in the Mojave Desert." 

She explained that this location is near the Calico fault, which crosses the Mojave. "It is more than 50 km from the Calico-Hidalgo fault zone  so it will not change the probability of a San Andreas earthquake," Jones said on X. 

Could this San Bernardino earthquake be a foreshock to a bigger one?

As this Barstow earthquake was on the Calico-Hidalgo fault zone, its proximity to the San Andreas fault begs the question if this could this be a foreshock of something bigger to come. Gabrielle Tapp, Caltech staff seismologist explained the liklelihood of this being the case is pretty slim. 

"The terms foreshocks and aftershocks are terms for how the earthquakes are once the entire sequence is finished. So we don't know what's a foreshock until everything is over...," Tapp said. "I think it's about a 5 percent chance in Southern California that an earthquake like this could become a  foreshock."

Tapp explained that this earthquake was a strike slip quake, where two sides of a fault rub laterally, the same what the San Andreas Fault would produce. She said most Southern California earthquakes are a strike slip.