A magnitude 6-4 earthquake was felt throughout the Southland Thursday, shaking up local residents celebrating the Fourth of July.
The quake, which began at 10:35 a.m., was centered about 7 miles southwest of Searles Valley, a sparsely populated part of the Mojave Desert in northwestern San Bernardino County, according to the U.S. Geological Survey.
Southland police and fire agencies quickly took to social media, reporting no injuries from the shaking, but some possible damage and one structure fire.
The Los Angeles Department of Water and Power reported a water main break on Wilshire Boulevard and La Jolla Avenue, power outages affecting the Garment District downtown, a portion of San Pedro, and 20 customers in Granada Hills.
The Los Angeles County Fire Department’s Division 8, which encompasses Diamond Bar, Hacienda Heights, Industry, Rowland Heights, La Puente, Walnut, Pomona and Valinda, reported that a structure fire possibly ignited from a gas line break due to the earthquake.
The Los Angeles, Beverly Hills and Pasadena police departments reported that no damages has been called in response to the reported 10:33 a.m. shaker.
The City of Anaheim reported that the city has no immediate issues and the Laguna Beach Police Department advised their citizens to be “safe wherever you are and watch out for those earthquakes.”
The Los Angeles Fire Department reported that “all 106 fire stations are out conducting a strategic survey of their districts to determine if any damage exists. Once this process is complete, an overall assessment of the impact in the City of Los Angeles will be compiled.”
The Los Angeles Police Department reported that they have not received any reports of damage or calls for service within the city in relation to the earthquake.
Officials at LAX said all runways were inspected and no damage was found.
Ride operations were briefly suspended at Six Flags Magic Mountain and Hurricane Harbor in Santa Clarita, but the theme parks tweeted shortly after the quake that operations had resumed as normal.
Southland police agencies were reminding the public not to use 911 for earthquake questions unless they have injuries or dangerous conditions to report.
It was the strongest quake to be felt in Southern California since 1999, according to seismologist Lucy Jones of Caltech, founder of the Dr. Lucy Jones Center for Science & Society.
Jones said the quake was not on the San Andreas fault.
“It is an area with a lot of little faults but no long fault,” she tweeted.
Jones said the “shake alert” computer system at Caltech’s seismic facility registered a 48-second warning that shaking had begun, but the warning signal did not go out to the public.
Los Angeles officials later explained that, tweeting: “The #ShakeAlertLA app only sends alerts if shaking is 5.0+ in LA County. Epicenter was 6.4 in Kern County, ??@USGS?? confirms LA*s shaking was below 4.5. We hear you and will lower the alert threshold with ??@USGS_ShakeAlert??”
A magnitude 4.2 quake that preceded the main quake by about 30 minutes was a “foreshock,” Jones said.
Officials with the San Bernardino County Fire Department tweeted that they were conducting an assessment of the region and “no injuries reported, however buildings and roads have sustained varying degrees of damage.”
A later tweet said multiple buildings had been found with minor cracks, along with broken water mains, downed power lines and rockslides on certain roads.
Several aftershocks in the magnitude-3 range were reported by the USGS, as expected following a substantial quake. Jones said there was a better than 50-percent chance of a larger aftershock in the magnitude-5 area “sometime this afternoon.”