Friday, April 24, 2009
By: Associated Press
YORBA LINDA, Calif. — Three earthquakes, the largest measuring magnitude 4.0, struck the Orange County area of Southern California late Thursday but no damage was reported.
The quakes were centered within a few miles of the city of Yorba Linda within less than four hours.
A magnitude-3.8 quake occurred at 4:56 p.m., followed by the 4.0 at 8:27 p.m. and a 3.0 less than a minute later at 8:28 p.m., the U.S. Geological Survey said.
Orange County sheriff's Lt. Tom Slayton said no damage was reported.
Yorba Linda immediately evacuated City Hall as a precaution after the first quake. A few books fell off a shelf but there was no damage, said Mark Aalders, assistant to the city manager.
"It was almost like, basically someone tugging you all of a sudden," Aalders said. "It was one brief jolt."
Seismologist Lucy Jones at the USGS office in Pasadena said the 3.0 quake was an aftershock of the 4.0.
"Each earthquake makes another earthquake more likely," she said.
The epicenter of first quake was 1 mile north-northwest of Yorba Linda, according to revised data. The second and third epicenters were 2 miles northeast of the city.
"It's not quite the same place as the one earlier this afternoon. It's a slight shift in location," said Jones.
Jones said the 4.0 occurred on a fault parallel to the Whittier Fault, a moderately active fault that stretches about 30 miles from eastern Los Angeles County south to northern Orange County.
The shaking occurred near the location of last year's magnitude-5.4 temblor, centered in neighboring Chino Hills, that rattled a large swath of Southern California. The area has had a series of mostly minor earthquakes since March.
Peter Chuang, manager of Wing's Chinese Restaurant in Yorba Linda said the second quake shook for about 15 seconds.
"It felt very strong," Chuang said. "Some customers were very nervous and asked to take their food home so they could check on their houses."