LOS ANGELES – A magnitude 4.2 earthquake rattled buildings and nerves across a wide swath of Southern California on Friday morning, but thankfully caused no damage or injuries.
According to the U.S. Geological Survey, the quake struck at 10:55 a.m. with an epicenter 5.5 miles under Lytle Creek, just north of Rancho Cucamonga, in the San Gabriel Mountains.
The temblor had a preliminary magnitude of 4.6 but was downgraded to 4.1 and, eventually, the Geological Survey determined it was a 4.2.
The Los Angeles Fire Department quickly stated that it was in “normal operating mode” with no reports of injuries, structure or infrastructure damage within the city.
An interactive USGS map shows shockwaves extended across Los Angeles, Riverside, San Bernardino, Orange and San Diego counties.
“I just heard a loud boom and the whole building kind of shook [and] all the windows,” recalled Emmanuel Ruiz, who was working at a bus warehouse in Rancho Cucamonga when the quake struck.
“My wife and I were sitting in the front of the room and all of the sudden… Bam! It hit,” Bob Dahlstein, another Rancho Cucamonga resident, told KTLA.
Ernesto and Jeanie Moreira captured video of the quake shaking their living room in North Fontana and spooking their dog, Coco.
“He was so scared,” Ernesto told KTLA.
Dr. Lucy Jones, SoCal’s preeminent seismologist, said the earthquake occurred where the San Andreas and San Jacinto faults intersect, which has been the site of previous quakes.
“In 1970, there was a [magnitude] 5.2 with a 4.0 foreshock in close to the same location,” Jones tweeted.
Southern California averages about ten earthquakes with a magnitude of 4.0 or greater every year, so Jones says Friday’s temblor is no cause for alarm.
“We had a 4.1 [quake] on New Year’s Day down by Palos Verdes and then this 4.2. But with a long-term average of about once a month, having two within a week is just normal variability,” she told KTLA.
Los Angeles Mayor Karen Bass also reassured residents 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 http://ReadyLA.org,” 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.