Latest quake highlights Los Angeles seismic danger
May 19, 2009 By ALICIA CHANG , AP Science Writer
Map shows earthquake that struck Los Angeles with population density
(AP) -- The latest earthquake to hit the nation's second-largest city was a garden-variety temblor by California standards, rumbling through on a Sunday evening when most residents were home eating dinner or watching TV. The magnitude-4.7 quake shattered more nerves than glass, and scientists say it could have been worse.
The quake, centered three miles east of Los Angeles International Airport, appeared to have ruptured a fault under the city that is capable of producing a damaging magnitude-7 temblor.
"Anytime you have a fault running through a densely populated urban area, it's on the watch list," said geophysicist Ken Hudnut of the U.S. Geological Survey.
The shaking Sunday lasted about 15 seconds, but it was felt across a wide swath of Southern California, which has not had a disastrous temblor since the magnitude-6.7 Northridge earthquake in 1994.
Sunday's quake released 1,000 times less energy than Northridge.
No major injuries were reported, though a person at a Starbucks in the coastal community of Torrance was taken to the emergency room with minor injuries. The quake caused minor property damage in beach towns south of the airport including a drapery business that had its storefront window knocked out.
The rattling spurred some to think about earthquake preparedness.
Long Beach resident Charlene Ebright said she hadn't updated her quake emergency kit in eight years but now plans to do so.
"I've cut out a million articles about what to do and what you need but I've never gotten around to it," Ebright said. "It just reminds you, you've got to be ready."
Scientists poring through data say the quake appeared to have caused slippage of the Newport-Inglewood fault, one of a half-dozen major fault lines crisscrossing the heavily populated Los Angeles Basin. While the fault, which extends more than 46 miles from Beverly Hills southeast to Orange County, is not considered as dangerous as the San Andreas Fault to the east, scientists are worried because of its proximity to cities.
"The fault is very centrally located. That's obviously why so many people felt it. It's right in the LA Basin," said Susan Hough, scientist in charge of the USGS Pasadena office.
Rupture along the Newport-Inglewood fault caused the 1933 magnitude-6.4 Long Beach quake that killed 120 people and caused more than $50 million in damage. The shaking crumpled buildings, knocked houses off their foundations and badly damaged many schools, which led to statewide quake-resistant construction.
Studies have shown the Newport-Inglewood fault is capable of unleashing a magnitude-7 temblor, though scientists are unsure how often such big quakes occur.
In 1988, the state Division of Mines and Geology, now called the California Geological Survey, released a report detailing the devastation of such a quake.
Under the scenario, numerous major highways would be damaged or blocked. Damage to access routes to LAX would reduce the airport's capacity as much as 30 percent. The shaking could start an oil refinery blaze and damage natural gas lines and mains.
A 1995 analysis by a Stanford University professor and a risk management firm estimated that a magnitude-7 temblor on the Newport-Inglewood fault could cause as much as $220 billion in damage.
By comparison, Sunday's quake was on the small side. Still, it was a watercooler moment for some residents.
Nathan Bruce, a 30-year-old barista at a Starbucks in Tustin, was on his weekly webcam chat with his mother in California's Central Valley when the earthquake hit. Initially, his mother didn't believe him when he told her he was in the middle of a temblor.
"I told her, `We're having an earthquake right now!'"
That didn't stop the conversation.
"Come on, we're from California. It's an earthquake," he said. "So what?"
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On the Net:
USGS earthquake page: http://earthquake.usgs.gov/
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