5.4 earthquake rocks Los Angeles area; minor injuries, damage reported

A strong earthquake with a preliminary magnitude of 5.4 jolted large parts of Southern California late this morning, shaking a wide swath from Ventura County to San Diego and causing minor damage and a few injuries.

The quake rattled buildings in downtown Los Angeles and was felt as far east as Palm Springs. It was centered near Chino Hills, about 30 miles east of Los Angeles, the U.S. Geological Survey said.

"It felt like something had exploded underneath us," said Vanessa Rojas, 21, a hair salon employee at Blondie's Clip Shop in nearby Chino. "The ground lifted, then it began to shake. It was a big ripple."

There were minor injuries and structural damage at the St. Jude Centers for Rehabilitation and Wellness in nearby Brea, an outpatient medical facility, according to a representative. TV helicopter footage of the Chino Hills area showed people being evacuated from schools and some buildings, but no major damage.

Pomona City Hall was closed as workers surveyed the damage, which was mostly broken glass. On the northern side of the building's third floor, a worker used a shovel to remove what little glass remained in a large window frame.

By midafternoon, some normalcy was returning. Nerves were still frayed in Chino Hills, but lives otherwise had largely returned to pre-quake status. At the Vons supermarket on Chino Hills Parkway, for example, all the aisles had been cleaned up two hours after the quake toppled glass jars off shelves and sent plastic containers bouncing to the floor.

The magnitude of the quake, which struck at 11:42 a.m., was originally set at 5.8. Caltech officials later downgraded it to 5.4 and said they doubted the temblor caused major structural damage.

Kate Hutton, a staff seismologist at Caltech, said that by 12:30 p.m., 27 aftershocks had been recorded at various sites, with the largest measuring 3.8. Today's temblor "was somewhat similar to the [1987] Whittier Narrows [quake]," Hutton said. "Most everyone in the L.A. Basin felt it. Things will have fallen off shelves. I'd be surprised to see some structural damage. There could be some cases of cracked plaster and maybe broken windows, but not structural damage, which is when a building is compromised."

She called the quake an "oblique slip on a thrust fault," which means one plate slides over another one.