Southern California jolted by magnitude 4.2 earthquake

An earthquake measuring 4.2 in magnitude shook the Los Angeles area Friday morning and was felt by potentially millions of people across Southern California.

According to the U.S. Geological Survey, the quake struck at 10:55 a.m. Pacific time with an epicenter 5.5 miles underground, just north of Rancho Cucamonga in the San Gabriel Mountains.

The temblor, dubbed the Lytle Creek Earthquake, had a preliminary magnitude of 4.6, was downgraded to 4.1 and eventually the Geological Survey determined it was a 4.2.

There were no immediate reports of damage or injuries.

“The Los Angeles Fire Department remains in a normal operating mode. There have been NO reports of injury, structure or infrastructure damage within our @LACity jurisdiction related to the M4.1,” LAFD posted on X, formerly Twitter.

Dr. Lucy Jones, a seismologist and founder of the Dr. Lucy Jones Center for Science and Society, said the earthquake occurred along two fault lines.

A map showing the epicenter and shockwaves of a magnitude 4.2 earthquake on Jan. 5, 2024. (USGS)

“The [quake was] near Lytle Creek in Cajon Pass, where the San Andreas and San Jacinto faults come together. In 1970, there was a M5.2 with a M4.0 foreshock in close to the same location,” Jones tweeted.

An interactive USGS map shows shockwaves extended across Los Angeles, Riverside, San Bernardino, Orange and San Diego counties.

L.A. Mayor Karen Bass reassured Angelenos that the quake, while alarming, did not cause damage, and she also took the opportunity to encourage residents to be prepared.

“This is a reminder that earthquakes can happen at any time. Make a plan to prepare for emergencies at,” the mayor tweeted.

Tens of thousands of earthquakes are recorded in California each year; however, the vast majority of them are extremely minor. Only several hundred are stronger than magnitude 3.0, and only about 15 to 20 are greater than magnitude 4.0, according to the USGS. 

This is a developing story. Stay with KTLA 5 News for updates.