It was the strongest SoCal quake in three years. Here's why it packed such a punch in L.A. (2024)

A magnitude 5.2 earthquake, centered about 18 miles southwest of Bakersfield, was felt across a wide swath of Southern California on Tuesday night.

Its size rattled nerves but caused no major damage or injuries. Two minutes after the earthquake hit, a large boulder — the size of an SUV — was reported blocking multiple southbound lanes of Interstate 5, about a mile south of Grapevine Road, the California Highway Patrol said. The boulder was cleared by Wednesday morning.

The earthquake, originally estimated at magnitude 5.3, struck at 9:09 p.m., according to the U.S. Geological Survey. It was followed by dozens of aftershocks of magnitude 2.5 and up, including a magnitude 4.5 earthquake that occurred less than a minute after the first, and a magnitude 4.1 temblor at 9:17 p.m.

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The epicenter was in sparsely populated farmland, about 14 miles northwest of the unincorporated community of Grapevine in Kern County, 60 miles northwest of Santa Clarita, and about 88 miles northwest of downtown Los Angeles.

The area closest to the epicenter felt “very strong” shaking as defined by the Modified Mercalli Intensity Scale; that zone includes a section of the California Aqueduct, which transports water from Northern California to Southern California.

By the time shaking was felt in more populated areas, including Bakersfield, Santa Clarita and Ventura, the USGS calculated that only “weak” shaking was felt, which can rock standing cars and cause vibrations in a building similar to the passing of a truck.

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Some residents affected by the quake reported an extended period of shaking. One person in Los Feliz felt 45 seconds of movement, with at least three different waves — one weak, followed by a strong one, then again a weak one. In South Pasadena and Whittier, people felt about 20 seconds of shaking, contained in two distinctive waves.

In Pasadena, seismologist Lucy Jones said she felt about three seconds of shaking.

There were no immediate reports of damage. And not everyone felt the earthquake. L.A. County Sheriff’s Deputy Jose Gomez said he didn’t feel the shaking during his drive into work at the sheriff’s Santa Clarita station. No damage was reported there.

The Los Angeles Fire Department said no significant damage was reported within city limits. Preliminary inspections of the State Water Project facilities, including the California Aqueduct, found no damage.

The USGS said the quake was felt across 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, such as through the MyShake app or on their Android phones. (The earthquake early warning system is automatically installed on Android phones, but people with Apple iOS phones need to install the MyShake app to get the most timely alerts.)

One person described getting 30 to 45 seconds of warning before feeling the shaking arrive. Another person, in east Anaheim, reported 30 seconds of warning before shaking arrived.

Jones, a research associate at Caltech, said the duration of shaking can vary so much in the L.A. area because the length of time the earth moves at any given spot can depend on the soil and rocks beneath the location, whether a person is sitting still or moving around, and even whether an individual is on the ground floor or on top of a skyscraper — those on higher floors feel the shaking more strongly.

The reason some people may have felt more than one wave of shaking is that the first aftershock occurred so soon — less than a minute — after the main shock, Jones said.

Geophysics professor Allen Husker, head of the Southern California Seismic Network at Caltech, said it wasn’t surprising that so many people in the L.A. area felt significant shaking from a magnitude 5.2 earthquake north of the Grapevine. The temblor occurred at night, when people are resting and more likely to feel shaking from a distant quake than if they were out and about during the day and active.

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Another reason many people felt substantial movement is due to the way shaking is amplified in the Los Angeles Basin. The basin is a 6-mile-deep, bathtub-shaped hole in the underlying bedrock filled with weak sand and gravel eroded from the mountains and forming the flat land where millions of people live. It stretches from Beverly Hills through southeast L.A. County and into northern Orange County.

“The basin effect ... increases the shaking that you would otherwise normally have,” Husker said.

The effect happens when waves from the shaking arrive and hit the walls of the basin, then bounce back at the walls of the basin, Jones said, resulting in an “extended duration.”

A major earthquake on the San Andreas fault would result in perhaps 50 seconds of strong shaking in downtown L.A. “This earthquake was much, much smaller, of course,” Jones said, “but it was large enough to set up some of these basin effects and get things bouncing around.”

As with all earthquakes, there was a 1 in 20 chance that Tuesday’s temblor was a foreshock to a larger earthquake. The risk that a follow-up quake will be larger diminishes over time.

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It has been several years since a magnitude 5.2 or greater earthquake hit Southern California, and Tuesday’s quake was the strongest to strike the region in three years. A magnitude 5.3 quake occurred in June 2021 just southeast of the Salton Sea in Imperial County, about 160 miles southeast of downtown Los Angeles. And in June 2020, a magnitude 5.5 quake struck the Mojave Desert in the northwestern corner of San Bernardino County, about 120 miles northeast of downtown L.A. and about 14 miles east of Ridgecrest in Kern County.

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The 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, according to the USGS, old and poorly built masonry buildings suffered damage. Some of those structures collapsed in communities including Tehachapi, Bakersfield and Arvin; heavy damage was reported at Kern County General Hospital.

Shaking from the 1952 earthquake was felt as far away as San Francisco and Las Vegas, and caused nonstructural but extensive damage to tall buildings in the Los Angeles area and damage to at least one building in San Diego, according to the USGS.

The 1952 earthquake occurred on the White Wolf fault. Tuesday’s earthquake wasn’t associated with any previously mapped faults.

Times staff writers Jon Healey, Ian James, Jason Neubert, Sandra McDonald and Raul Roa contributed to this report.

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It was the strongest SoCal quake in three years. Here's why it packed such a punch in L.A. (2024)

FAQs

It was the strongest SoCal quake in three years. Here's why it packed such a punch in L.A.? ›

It was the strongest SoCal quake in three years. Here's why it packed such a punch in L.A. The magnitude 5.2 earthquake near Bakersfield was felt over a wide area of Southern California. Experts say there are several reason for this, including its size, time of night and the so-called 'basin effect.'

How strong was the earthquake that hit Southern California? ›

4.4-magnitude earthquake hits Southern California.

Has California ever had a 9.0 earthquake? ›

North Coast

The Cascadia Subduction Zone stretches underneath the Humboldt-Del Norte county region, extending from Cape Mendocino all the way up through the Pacific Northwest. This fault zone is capable of generating a magnitude 9 (or larger) earthquake on average every 500 years. The last such event was in 1700.

What year was the 7.2 earthquake in California? ›

Mainshock. The earthquake measured 7.2 on the moment magnitude scale that started 25 kilometers (16 mi) south of Guadalupe Victoria, Baja California, at a depth of 10 km (6.2 mi). It occurred at 22:40 UTC (1540 local time) on Easter Sunday, April 4, 2010, and it is said to have lasted about a minute and 29 seconds.

Has there ever been a 10.0 earthquake? ›

A fault is a break in the rocks that make up the Earth's crust, along which rocks on either side have moved past each other. No fault long enough to generate a magnitude 10 earthquake is known to exist, and if it did, it would extend around most of the planet.

What size earthquake would destroy California? ›

The San Andreas fault system could create the biggest earthquakes in the region—as big as magnitude 8—that would disrupt a wide-ranging area of the Central Valley. But smaller magnitude earthquakes could also cause damaging levels of ground shaking.

Can California have a 10.0 earthquake? ›

Fact: Strictly speaking, mega-quakes of magnitude 10 or more are possible; however, scientists agree that they are implausible. The magnitude of an earthquake is related to the length of the fault on which it occurs—the longer the fault, the larger the earthquake. The San Andreas Fault is only 800 miles long.

Could an earthquake sink California? ›

A prominent myth about earthquakes in California is the idea that a big enough rattle could cause the Golden State to fall into the sea. Experts said the shaking from earthquakes cannot cause California to sink, however, earthquakes can spark landslides that slightly change the shape of the coastline.

What city has the highest probability of an earthquake in California? ›

San Francisco Bay area:

Within the next 30 years the probability is: 72% that an earthquake measuring magnitude 6.7. 51% that an earthquake measuring magnitude 7. 20% that an earthquake measuring magnitude 7.5.

Has there been a 7.8 earthquake in California? ›

What history tells us. The last California seismic event that reached magnitude 7.8 was the great San Francisco earthquake of 1906. In Southern California, a magnitude 7.8 quake struck in 1857.

What kills most people in earthquakes? ›

Most earthquake-related injuries and deaths result from collapsing walls, flying glass, and falling objects caused by the ground shaking.

What part of California is safest from earthquakes? ›

Cities like Sacramento, Fresno, and San Diego often top the list due to their geographical locations which are relatively distant from the San Andreas Fault. Sacramento, for instance, benefits from its position in the valley, which experiences less seismic activity compared to coastal and mountainous regions.

When was the last 7.1 earthquake in California? ›

U.S. Geological Survey, "Update: Magnitude 7.1 Earthquake in Southern California," July 6, 2019.

Has California ever had an 8.0 earthquake? ›

There has never been a 8.0 earthquake in California; the strongest on record is a 7.9 near Fort Tejon in 1857, according to the state's Department of Conservation.

Which state has the most earthquakes? ›

Alaska is the most earthquake-prone state and one of the most seismically active regions in the world. Alaska experiences a magnitude 7 earthquake almost every year, and a magnitude 8 or greater earthquake on average every 14 years.

How big was the 1971 earthquake in California? ›

On February 9, 1971 at 6:01 am PST, a devastating M6. 6 earthquake struck the densely populated metropolitan area of Los Angeles, leaving death and destruction in its wake. The epicenter of the earthquake was in the vicinity of Magic Mountain, about six miles northeast of Sylmar, at a depth of about seven miles.

What town in Southern California had a 7.6 earthquake in 1952? ›

Seventy years after the main event on July 21st, 1952, it has been forgotten by many, but still remains a significant event in the history of seismology. The earthquake occurred on the White Wolf fault near Bakersfield, California, close to the intersection of the San Andreas fault and the Garlock fault.

How big was the 1994 earthquake in California? ›

On January 17, 1994, at 4:31 a.m. PST, a magnitude 6​. 7 earthquake centered in Northridge struck the southern California area. Known as the Northridge Earthquake, it caused at least 57 fatalities (a subsequent study put the death toll at 72, including heart attacks) and injured thousands.

What was the biggest earthquake on the San Andreas fault? ›

Earthquake Science

The largest historical earthquake on the northern San Andreas was the 1906 magnitude 7.9 earthquake. In 1857 the Fort Tejon earthquake occurred on the southern San Andreas fault; it is believed to have had a magnitude of about 7.9 as well.

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