California earthquake related to April's Baja quake
The Associated Press
Published Thursday, July 8, 2010 10:21AM EDT
LOS ANGELES - A moderate earthquake that rattled through Southern California with only minor damage and no injuries came as no surprise to seismologists, who said it was triggered by a much larger April temblor near the U.S.-Mexico border.
The 5.4-magnitude earthquake rattled buildings in downtown Los Angeles Wednesday, toppled wine bottles at desert resorts and briefly halted rides at Disneyland.
It was centred 28 miles (45 kilometres) south of Palm Springs and was related to the powerful Easter Day quake, but was not an aftershock, researchers said.
California Institute of Technology Seismologist Kate Hutton said the 7.2-magnitude quake in April transferred stress to fault zones farther north, triggering the quake that was felt from San Diego to Los Angeles to Las Vegas on Wednesday afternoon.
Preliminary information indicates the quake was on the San Jacinto fault, the most seismically active fault in California and one of two that exhibited signs of increased pressure following the Mexico quake, according to a recent airborne analysis by the NASA Jet Propulsion Laboratory.
The upshot is that the Easter quake appeared to have decreased the stress on the southernmost San Andreas Fault -- slightly lowering the chance of a quake on the mother of California faults.
"You can't predict earthquakes, but our statistics said there would be an increased chance of this happening," said California Instituted of Technology seismic analyst Anthony Guarino.
The moderate earthquake rattled buildings 130 miles (210 kilometres) away in downtown Los Angeles, toppled wine bottles at desert resorts and send people scurrying under desks and tables across the Coachella Valley.
There were no reports of injuries or major damage.
The quake struck just before 5 p.m. (0000 GMT) and was followed by dozens of aftershocks, according to the U.S. Geological Survey.
Laura Anderson, a manager at The Palms at Indian Head Hotel, said she ran outside when the shaking started and was surprised to learn the temblor's magnitude wasn't higher.
"It was enough to knock over some wine bottles and some pictures fell off the wall," Anderson said.
Police Lt. John Booth said there were no reports of serious damage or injuries in Palm Springs, a desert city of about 43,000, but the phone rang off the hook and many residents were shaken up by the largest quake they could remember.