A magnitude 5.2 earthquake, centered about 18 miles southwest of Bakersfield, was felt throughout a large swath of Southern California on Tuesday evening.
The earthquake, initially estimated at magnitude 5.3, struck at 9:09 p.m., in response to the U.S. Geological Survey. It was adopted by dozens of aftershocks of magnitude 2.5 and up, together with a magnitude 4.5 earthquake that occurred lower than a minute after the primary, and a magnitude 4.1 temblor at 9:17 p.m.
The epicenter was in sparsely populated farmland, about 14 miles northwest of the unincorporated group of Grapevine in Kern County, 60 miles northwest of Santa Clarita, and about 88 miles northwest of downtown Los Angeles.
Two minutes after the earthquake hit, a big boulder — the dimensions of an SUV — was reported blocking a number of southbound lanes of Interstate 5, a couple of mile south of Grapevine Street, the California Freeway Patrol stated. The boulder was nonetheless blocking lanes of visitors not less than an hour after the earthquake.
The world closest to the epicenter felt “very sturdy” shaking as outlined by the Modified Mercalli Depth Scale; that zone features a part of the California Aqueduct, which transports water from Northern California to Southern California.
By the point shaking was felt in additional populated areas, together with Bakersfield, Santa Clarita and Ventura, the USGS calculated that solely “weak” shaking was felt, which may rock standing vehicles and trigger vibrations in a constructing much like the passing of a truck.
Some residents affected by the quake reported an prolonged interval of shaking. One individual in Los Feliz felt 45 seconds of motion, with not less than three totally different waves — one weak, adopted by a robust one, then once more a weak one. In South Pasadena and Whittier, individuals felt about 20 seconds of shaking, contained in two distinctive waves.
In Pasadena, seismologist Lucy Jones stated she felt about three seconds of shaking.
There have been no speedy studies of injury. And never everybody felt the earthquake. L.A. County Sheriff’s Deputy Jose Gomez stated he didn’t really feel the shaking throughout his drive into work on the sheriff’s Santa Clarita station. No injury was reported there.
The Los Angeles Hearth Division stated no important injury was reported inside metropolis limits.
The USGS stated the quake was felt throughout the Los Angeles Basin and inland valleys and in Santa Maria, Bakersfield and Fresno.
Many Southern California residents described getting alerts from the USGS’ earthquake early warning system, reminiscent of by the MyShake app or on their Android telephones. (The earthquake early warning system is mechanically put in on Android telephones, however individuals with Apple iOS telephones want to put in the MyShake app to get probably the most well timed alerts.)
One individual described getting 30 to 45 seconds of warning earlier than feeling the shaking arrive. One other individual, in east Anaheim, reported 30 seconds of warning earlier than shaking arrived.
Jones, a analysis affiliate at Caltech, stated the period of shaking can range a lot within the L.A. space as a result of the size of time the earth strikes at any given spot can rely on the soil and rocks beneath the situation, whether or not an individual is sitting nonetheless or shifting round, and even whether or not a person is on the bottom flooring or on prime of a skyscraper — these on increased flooring really feel the shaking extra strongly.
The explanation some individuals might have felt multiple wave of shaking is that the primary aftershock occurred so quickly — lower than a minute — after the primary shock, Jones stated.
Geophysics professor Allen Husker, head of the Southern California Seismic Community at Caltech, stated it wasn’t shocking that so many individuals within the L.A. space felt important shaking from a magnitude 5.2 earthquake north of the Grapevine. The temblor occurred at evening, when individuals are resting and extra prone to really feel shaking from a distant quake than in the event that they had been out and about in the course of the day and energetic.
Another excuse many individuals felt substantial motion is because of the means shaking is amplified within the Los Angeles Basin. The basin is a 6-mile-deep, bathtub-shaped gap within the underlying bedrock stuffed with weak sand and gravel eroded from the mountains and forming the flat land the place tens of millions of individuals reside. It stretches from Beverly Hills by southeast L.A. County and into northern Orange County.
“The basin impact … will increase the shaking that you’d in any other case usually have,” Husker stated.
The impact occurs when waves from the shaking arrive and hit the partitions of the basin, then bounce again on the partitions of the basin, Jones stated, leading to an “prolonged period.”
A serious earthquake on the San Andreas fault would end in maybe 50 seconds of sturdy shaking in downtown L.A. “This earthquake was a lot, a lot smaller, after all,” Jones stated, “but it surely was giant sufficient to arrange a few of these basin results and get issues bouncing round.”
As with all earthquakes, there was a 1 in 20 probability that Tuesday’s temblor was a foreshock to a bigger earthquake. The danger {that a} follow-up quake can be bigger diminishes over time.
Within the final 10 days, there had been no earthquakes of magnitude 3.0 or higher centered close by.
A mean of 5 earthquakes with magnitudes of 5.0 to six.0 happen per yr in California and Nevada, in response to a latest three-year knowledge pattern.
Tuesday’s earthquake occurred about 12 miles northwest of the epicenter of the magnitude 7.5 Kern County earthquake that struck on July 21, 1952. That earthquake resulted in 12 deaths, and, in response to the USGS, outdated and poorly constructed masonry buildings suffered injury. A few of these buildings collapsed in communities together with Tehachapi, Bakersfield and Arvin; heavy injury was reported at Kern County Common Hospital.
Shaking from the 1952 earthquake was felt as far-off as San Francisco and Las Vegas, and prompted nonstructural however intensive injury to tall buildings within the Los Angeles space and injury to not less than one constructing in San Diego, in response to the USGS.
The 1952 earthquake occurred on the White Wolf fault. Tuesday’s earthquake wasn’t related to any beforehand mapped faults.
The earthquake occurred at a depth of 5.6 miles. Did you are feeling this earthquake? Take into account reporting what you felt to the USGS.
Discover out what to do earlier than, and through, an earthquake close to you by signing up for our Unshaken publication, which breaks down emergency preparedness into bite-sized steps over six weeks. Study extra about earthquake kits, which apps you want, Lucy Jones’ most vital recommendation and extra at latimes.com/Unshaken.
The primary model of this story was mechanically generated by Quakebot, a pc software that screens the newest earthquakes detected by the USGS. A Instances editor reviewed the submit earlier than it was printed. Should you’re excited by studying extra concerning the system, go to our record of incessantly requested questions.
Instances workers writers Jon Healey, Ian James, Jason Neubert, Sandra McDonald and Raul Roa contributed to this report.