LOS ANGELES — A strong earthquake shook Southern California on Tuesday, causing buildings to sway and triggering some precautionary evacuations. There were no immediate reports of major damage or serious injuries.
The 5.4-magnitude quake — considered moderate — was felt about 11:42 a.m. from Los Angeles to San Diego, and as far east as Las Vegas, 230 miles away. Nearly 30 aftershocks quickly followed, the largest estimated at 3.8.
The quake was centered 29 miles southeast of downtown Los Angeles near Chino Hills, a San Bernardino County city of 80,000 built mostly in the early 1990s with the latest in earthquake-resistant technology.
Buildings swayed in downtown Los Angeles for several seconds, leading to the evacuation of some offices.
"I'm still shaking. My knees are wobbling. I thought the building might collapse," said Rosana Martinez, 50, who works in a fifth-floor office at the California National Bank in downtown Los Angeles.
Not a killer quake
The quake initially was estimated at 5.8 but was revised downward to magnitude-5.4, said seismologist Kate Hutton of the U.S. Geological Survey office in Pasadena. The USGS estimated the quake was about 8 miles below the earth's surface.
"It will certainly cause cracked plaster and broken windows, but probably not structural damage," Hutton said.
As strong as it felt, Tuesday's quake was far less powerful than the deadly magnitude-6.7 Northridge earthquake that toppled bridges and buildings on Jan. 17, 1994. That was the last damaging temblor in Southern California, though not the biggest. A 7.1 quake struck the desert in 1999.
The earthquake had about 1 percent of the energy of the Northridge quake, said Thomas Heaton, director of the earthquake engineering and research laboratory at the California Institute of Technology.
The magnitude-5.9 Whittier Narrows quake in 1987 was the last large one centered in the region hit Tuesday. That quake heavily damaged older buildings and houses in communities east of Los Angeles.
"People have forgotten, I think, what earthquakes feel like," said Hutton. "So I think we should probably look at it as an earthquake drill. ... It's a drill for the `Big One' that will be coming some day."
'Get under the tables'
Disneyland visitor Clint Hendrickson, 32, said he was in the Golden Horseshoe theater watching a show when the temblor hit.
"The ground moved and the chandelier started shaking," he said. "We are from Texas and we thought it was part of the show, until people started yelling, 'Get under the tables!'"
Attractions at Disneyland and Disney's California Adventure theme parks and at the Knott's Berry Farm theme park were temporarily closed for inspections after the shaking.
The quake interrupted a meeting of the Los Angeles City Council, causing the 27-story City Hall to sway just as Councilman Dennis Zine was criticizing a plan to increase trash fees.
"And there goes the earthquake — earthquake, earthquake, earthquake!" said Zine, as members of the audience began to cry out. "The building is rolling!"
Scattered reports of minor damage
California's Office of Emergency Services received scattered reports of minor infrastructure damage, including broken water mains and gas lines.
"Nothing serious enough to be an immediate threat to lives, but there is some disruption to utility service," spokesman Kelly Huston said. The damage was in the greater Los Angeles area.
Minor structural damage was reported throughout Los Angeles, along with five minor injuries and people stuck in elevators, said City Councilwoman Wendy Greuel, serving as acting mayor. She said there was flooding in one department store.
The California Department of Transportation and California Highway Patrol were assessing freeways to check for damage. Traffic appeared to be flowing easily, however.
"I think we were very lucky with this one," Gov. Arnold Schwarzenegger said.
'It was rolling'
The jolt caused a fire but no injuries at a Southern California Edison electrical substation in La Habra, about 12 miles southwest of the epicenter, spokesman Paul Klein said. Damage there and to other equipment led to some power outages in Chino Hills, Chino, Diamond Bar and Pomona, he said.
Near the epicenter, all the customers of a Chino Hills Starbucks ran outside and bags of coffee beans fell off shelves, worker Jamie Saleh said.
"It was very, very strong. It was rolling and ... there wasn't a pause," said Saleh, 24. "It came on really strong and just kept going."
Chino Hills was incorporated in 1991, so much of the construction is newer and built to modern safety standards, said city spokeswoman Denise Cattern. She said there were no reports of harm in the city of 80,000, although cell phone service in the area was disrupted. The biggest employer in town, the school district, is out of session.
"At this point, the biggest impact we can report is getting through on cell phones. ... And a few little rattled nerves," Cattern said.
More aftershocks expected
California is one of the world's most seismically active regions. More than 300 faults crisscross the state, which sits atop two of Earth's major tectonic plates, the Pacific and North American plates. About 10,000 quakes each year rattle Southern California alone, although most of them are too small to be felt.
Jeff Ranieri, a meteorologist with NBC Weather Plus, said the quake occurred along the Whittier and Chino fault lines, not the highly unstable San Andreas Fault.
The shallow nature of the quake helped to disperse the impact, spreading it over an area of about 100 miles. He said aftershocks up to magnitude 4.0 could be expected.
In Orange County, about 2000 detectives were attending a conference on gangs at a Marriott hotel in Anaheim when a violent jolt shook the main conference room.
Mike Willever, who was at the hotel, said, "First we heard the ceiling shaking, then the chandelier started to shake, then there was a sudden movement of the floor."
Chris Watkins, from San Diego, said he previously felt several earthquakes, but "that was one of the worst ones."
Pat Abbott, a geology professor at San Diego State University, said the area had been overdue for a sizable quake.
"We’re very lucky," Abbott told NBC affiliate KNSD of San Diego. A quake with a magnitude 7.0 has been expected in the region for some time, he said.
Joanne Hedge of Glendale Rancho, a suburb of Los Angeles, described "a giant thud which sounded like a sonic boom ... followed by 20 seconds of rapid, noisy shaking."
"This old house just rode it through as it has since 1939,” Hedge told KNBC.
'Our building shook pretty good'
Delegates and guests at a cluster of hotels near the Disneyland resort spilled into the streets immediately after the quake.
Joseph Maddalena, who runs the historical documents and memorabilia dealer Profiles in History, was on the phone in his office in Calabasas, near Malibu, when the earthquake struck. He quickly put down the phone and ran to check on his 14-year-old son who had come to work with him as he prepared for a Thursday auction of 1,100 pieces of Hollywood movie memorabilia.
"Our building shook pretty good," he said after discovering his son and his employees were unharmed and the building was fine.
"The window in my office kind of bowed out but it's all right now. Everything is fine," he said.
Alex Johnson of msnbc.com and NBC affiliates KNSD of San Diego and KNBC of Los Angeles contributed to this report from The Associated Press.
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