String of Southern California earthquakes no cause for alarm
Southern California residents might be feeling more than their fair share of shaking lately, after quakes in Beverly Hills, Yorba Linda and Imperial County in the last month. But experts said it's really not unusual.
"We have several of these things every week in California, but usually they're out somewhere where they don't get this kind of attention," said U.S. Geological Survey geophysicist Doug Given.
He said the Beverly Hills quakes attracted significant attention because they hit underneath a heavily populated area. Even the swarm of quakes in Imperial County — while strong and numerous — were far from rare.
The two earthquakes that struck Beverly Hills last week occurred at the junction of two major fault lines, one of which produced one of Southern California's deadliest temblors.
Both faults are quite long, meaning they are capable of producing a destructive quake.
The Newport-Inglewood fault, beginning just off the Orange County coast and extending 50 miles northwest through Long Beach, Inglewood and into Beverly Hills, has been the subject of dire quake scenarios because it runs directly under some of the most densely populated areas of Southern California.
The 1933 Long Beach quake was a magnitude 6.3 temblor centered off the Orange County coast that killed 115 people, mainly in Long Beach and Compton. That was the second-largest number of fatalities in a California earthquake in recorded history. Damage to school buildings from that quake led to major steps toward earthquake-resistant construction in the state.
A state study found that a quake along the Newport-Inglewood fault could block the 101 Freeway at the Hollywood and Sunset boulevard over-crossings, reduce the capacity of Los Angeles International Airport to 30% of normal for two days, remove for an indefinite period 34% of the hospital beds in Los Angeles and Orange counties, shut down five power plants for three days and contaminate water supplies.
A scenario simulating a 6.6 earthquake on the Santa Monica fault estimated that 54,000 buildings could be damaged, including 85 beyond repair. Under the scenario, a quake on the fault could kill as many as 30 people and force the hospitalization of more than 200 people.
The Beverly Hills earthquakes that hit last week -- a magnitude 3.2 on Monday, centered near Doheny Drive and Wilshire Boulevard, and a 3.4 after midnight Friday, centered near Wilshire Boulevard and Beverly Drive — were shallow.
In 2009, a 4.7 earthquake centered near Inglewood shattered some windows and caused ceiling tiles to fall in a movie theater.
The Beverly Hills temblors came the same week as a magnitude 7.6 earthquake in Costa Rica, but officials said they could see no connection.
— Rong-Gong Lin II