The quake, initially listed as a 5.2 before being downgraded, was the biggest to strike the larger Los Angeles area since a 5.4 in 2010, said U.S. Geological Survey seismologist Susan Hough. The relatively deep quake -- with an epicenter seven miles beneath the small town of Anza in the San Jacinto Mountains -- sent shock waves for hundreds of miles.
The tremor was similar to East Coast quakes, which send reverberations up to 10 times farther than West Coast earthquakes because of deeper faults and more solid bedrock.
There have been at least 100 aftershocks, according to the USGS. The largest, magnitude 3.2, struck less than a minute after the first quake. The second aftershock, magnitude 2.8, occurred at 11:25 a.m. Another 2.8 quake occurred at 12:50 p.m. The vast majority of the aftershocks were largely imperceptible, less than magnitude 2.5. Valleys and other low elevation areas feel the effects most strongly, Hough said.
No injuries or major damage were reported. KTLA News reported that at the Sunshine Market in Anza, a few products fell off shelves. But the temblor rattled nerves.Shannon Haber was in the Los Angeles Unified School District’s highrise in Westlake when the shaking began about 9:55 a.m.
“I was just a little frightened,” Haber said. “There was small shaking, and it made me nervous because I’m 23 floors up.”
Monday’s quake was bigger and lasted longer than any Haber has experienced since moving to the area from Minneosta in 1996.
“It was a slow, swaying motion,” she said. “It sort of felt like I was on a boat, a sort of wavy feeling that lasted 10 to 20 seconds.... No one else reacted around me. They’re all veterans of earthquakes.”
Holly Lawson was working in a campground kiosk at Anza-Borrego Desert State Park, about 60 miles south of the epicenter, when the windows in her tiny kiosk began to rattle Monday morning.
The rolling rumble lasted about six seconds, she said, and she could see a man outside in his truck as it swayed back and forth.
“The truck was actually physically moving,” Lawson said.
A San Diego native, she had already guessed the temblor's magnitude by the time the shaking stopped.
“I'm always concerned about these windows when we feel a quake,” she said. “We're surrounded by them.”
Lawson, who lives in Anza, got a call from her teenage son soon after. He reported there had been a sudden, loud crack of sound before the shaking began. Their home, a manufactured house, had experienced small cracks after a similar earthquake about a year ago.
Meanwhile, campers in nearby RVs came one by one to ask if that had, indeed, been an earthquake “or if they were just going crazy,” said Lawson.
-- Frank Shyong, Joseph Serna and Christine Mai-Duc
Photo: Quake damage in Anza. Credit: KTLA News