Magnitude 3.2 earthquake off coast sends weak shaking through Malibu, Westside of L.A.
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A magnitude 3.2 earthquake hit a few miles south of Malibu on Wednesday, sending a gentle jolt through the beachside city.
The earthquake struck at 9:33 a.m., and weak shaking was felt as far away as Los Angeles’ Westside, according to reports submitted to the U.S. Geological Survey’s crowdsourcing website. The epicenter was about 2.7 miles southwest of Malibu Point.
The offshore temblor comes just three weeks after a magnitude 5.2 earthquake, centered in eastern San Diego County, rumbled across Southern California — shattering bottles, wine glasses and pottery but otherwise causing little damage.
Wednesday’s earthquake also adds to the notable string of seismic activity in and around the Malibu area over the last 16 months.
Monday’s 5.2 magnitude temblor marked another success for California’s early earthquake warning system, with users in some areas saying they got notifications on their phone before they felt shaking.
Notable recent temblors include a magnitude 4.6 earthquake on Feb. 9, 2024; a magnitude 4.7 earthquake on Sept. 12, 2024; and a magnitude 4.1 earthquake on March 9.
But although all were relatively modest and left little damage, they serve as an uneasy reminder that Los Angeles County and Orange County haven’t seen a major earthquake in a long time.
Since 1998, there has been only one earthquake of magnitude 5 or greater under the two heavily populated counties. That was a magnitude 5.1 earthquake centered in Brea in 2014, which caused more than $2.5 million in damage in that city, Fullerton and La Habra.
There was also the magnitude 5.4 Chino Hills earthquake of 2008. Centered in San Bernardino County, but just east of Los Angeles and Orange counties, it caused little major damage.
While not a household name like the San Andreas, the Elsinore fault is part of a larger seismic zone that experts fear and believe more people should know about.
It has been 31 years since the magnitude 6.7 Northridge earthquake hit Los Angeles, and more than 35 years since the magnitude 6.9 Loma Prieta earthquake ruptured in Santa Cruz County, causing extensive damage across the San Francisco Bay Area.
Amid this relative seismic drought, some communities have recently made moves to improve seismic safety.
In December, the Burbank City Council unanimously approved a mandatory retrofit ordinance for apartment buildings with a flimsy first floor, known as a “soft story,” that can collapse in an earthquake. The well-known design flaw is often a result of having ground-floor carports or garages with skinny columns propping up the first floor, which can collapse when shaken side to side.
The law took effect on Jan. 19 and affects wood-framed buildings that are at least two stories tall and were built using building code standards enacted before 1978. The Burbank law requires that retrofits be completed by 2030.
One of the dangers may come as a surprise to homeowners, as even relatively newer homes may have this defect.
Burbank is offering refunds on building permit fees to property owners who complete their retrofits early.
More than a half-dozen cities in Southern California have already opted to require retrofit work on soft-story apartment buildings — Los Angeles, Torrance, Pasadena, Santa Monica, Culver City, West Hollywood and Beverly Hills. In Northern California, the list includes San José, San Francisco, Oakland, Fremont, Berkeley, Albany and Mill Valley.
However, a Times investigation published in November found that a number of suburbs in L.A. County had no active plans to require retrofits for these types of earthquake-vulnerable apartments.
In Northern California, the San Francisco Board of Supervisors unanimously approved a measure on Tuesday that will require owners of suspect concrete buildings to seismically evaluate their structures with an engineer.
Amid Southern California’s most seismically active year in decades, some cities have yet to require retrofits of many apartment buildings deemed most at risk of collapse.
The analysis will help determine if specific buildings are at particular risk of collapse or severe damage in an earthquake.
“This legislation helps us understand the actual risk to our building stock and provides concrete building owners with clear voluntary guidance and options for retrofits,” City Administrator Carmen Chu said in a statement.
The San Francisco law, however, does not require vulnerable concrete buildings to be retrofitted.
Officials in San Francisco estimate that half of all deaths and injuries in a projected hypothetical magnitude 7.2 earthquake on the San Andreas fault would occur in concrete buildings.
Monday’s magnitude 4.4 quake that rattled Southern California is believed to have struck on a well-known and dangerous fault system known as the Puente Hills thrust fault system.
One major flaw involves a concrete building being “non-ductile,” in which there is an inadequate configuration of steel reinforcing bars, which allows concrete to explode out of columns when shaken in an earthquake, a prelude to a catastrophic collapse. This flaw, now well known, was discovered in the 1971 Sylmar quake.
Concrete buildings have previously collapsed in Los Angeles earthquakes, including a Kaiser Permanente clinic building and a Bullock’s department store building during the 1994 Northridge earthquake, and the newly built Olive View Medical Center during the 1971 earthquake.
Collapses of concrete buildings have caused significant deaths in earthquakes in Turkey, Mexico, Taiwan and New Zealand.
Cities in California that require non-ductile concrete buildings to be retrofitted include Los Angeles, Torrance, Santa Monica and West Hollywood.
L.A. County’s proposed earthquake rules would require certain older concrete buildings in unincorporated areas, and those owned by the county, to be retrofitted.
Are you ready for when the Big One hits? Get ready for the next big earthquake by signing up for our Unshaken newsletter, which breaks down emergency preparedness into bite-size steps over six weeks. Learn more about earthquake kits, which apps you need, Lucy Jones’ most important advice and more at latimes.com/Unshaken.
An earlier version of this story was generated by Quakebot, a computer application that monitors the latest earthquakes detected by the USGS. If you’re interested in learning more about the system, visit our list of frequently asked questions.
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