A magnitude 2.6 earthquake struck Newport Beach on Wednesday afternoon, causing weak shaking in Orange County.
The earthquake’s epicenter was southeast of Costa Mesa, beneath Mariner Park. Light shaking was felt in Irvine, Santa Ana, Huntington Beach, Garden Grove, Tustin and Fountain Valley, according to people who reported the quake to the U.S. Geological Survey. website.
The earthquake occurred at 1:46 p.m. near the map trace of the Newport-Inglewood/Rose Canyon fault zone. In Santa Ana, some felt the quake first as a slow rumble, then as a rapid tremor.
The Newport-Inglewood Fault has long been considered one of Southern California’s greatest seismic hazards because it lies beneath some of the region’s most densely populated areas, from West Los Angeles to the Orange County coast.
The last major earthquake on this fault occurred in 1933, the magnitude 6.4 Long Beach earthquake. That earthquake was the deadliest in Southern California’s modern history, causing “very strong” tremors in Long Beach, Huntington Beach and Compton, designated a 7 on the Modified McCully Scale.
The 1933 earthquake killed nearly 120 people and caused $40 million in property damage.
Scientists say recent observations indicate a magnitude 6.8 to 7.5 earthquake on the Newport-Inglewood/Rose Canyon fault system, which runs from the border of Beverly Hills and Los Angeles through Long Beach and Orange The county coast extends all the way to downtown San Diego.
Research published in 2017 suggests that the Newport-Inglewood fault is more active than previously thought. If a magnitude 7.5 earthquake did rupture along this fault system, such an earthquake would cause massive damage throughout Southern California. A magnitude 7 earthquake would hit areas west of downtown Los Angeles particularly hard.
A 2017 study found evidence that large earthquakes on the fault centuries ago were so violent that they caused a portion of Seal Beach off the Orange County coast to drop 1 1/2 to 3 feet in a matter of seconds.
Wednesday’s quake was the fifth magnitude 2.0 or above to hit the Southern California metropolitan area in the past five days.
A 2.2-magnitude earthquake struck beneath the San Gabriel Mountains early Wednesday, less than two miles from the northern edge of Rancho Cucamonga in San Bernardino County. The quake struck at 5:01 a.m., down from an earlier estimated magnitude of 2.5
Two earthquakes struck the El Sereno neighborhood east of Los Angeles on Sunday and Tuesday. The first, a magnitude 3.4, hit a few blocks south of Huntington and Eastern avenues at 9:56 a.m. Sunday. The second earthquake, measuring 2.8 in magnitude, lower than the previous estimate of 3, occurred at 3:05 pm on Tuesday. The initial estimated epicenter was revised from below Elephant Mountain Open Space to farther south, about 700 feet northwest of Sunday’s quake.
A 3.6-magnitude earthquake struck at its epicenter north of the Ojai Valley at 10:26 a.m. Friday (down from the initial estimate of 3.8), causing weak tremors from Santa Barbara to Los Angeles.
Small earthquakes are not uncommon in Southern California. Most do not result in larger, catastrophic earthquakes. While some larger earthquakes are preceded by smaller earthquakes, this is not always the case.
It’s impossible to know whether a small earthquake is a “foreshock” of a larger one before a more powerful event occurs.
Times staff writer Gustavo Arellano contributed to this report.
