A predawn earthquake sent a sharp jolt across the Los Angeles area Tuesday, but the magnitude 4.4 temblor was barely strong enough to knock items off shelves.
It was, however, sharp enough to frazzle residents, many of whom felt a "strong bang." The epicenter was 10 miles southeast of downtown Los Angeles in Pico Rivera, and the quake was felt as far away as San Diego and Ventura County.
Los Angeles County fire official Ed Pickett, who was in East Los Angeles, said the jolt at 4:04 a.m. felt "like the building dropped." He described feeling the quake for about "15 seconds at the most."
But at the epicenter, there appeared to be no major damage. Not a single bottle broke at Walt's Liquor Store in Pico Rivera, said owner Letti Talamantes.
Jose Palomera, who was cleaning a taco stand in Pico Rivera, first thought the shaking was a rolling big rig. "It just felt like a big wave just passing by," he said.
Pico Rivera soon returned to normal. Buses picked up passengers, cars waited in drive-through lines and customers watched the morning news while buying doughnuts and coffee.
The quake was weaker than the magnitude 5.4 Chino Hills quake in July 2008 and the 4.7 May 2009 Inglewood quake, which shattered windows and caused minor damage.
Caltech seismologist Egill Hauksson said Tuesday’s quake appears to have occurred along the 25-mile-long Puente Hills thrust fault, which runs from the Puente Hills near Whittier northwest through downtown Los Angeles, ending in Beverly Hills. The quake was triggered when one side of the fault slid over the other, causing shaking.
The Puente Hills thrust fault is the same one that triggered the magnitude 5.9 Whittier Narrows earthquake in 1987 that killed eight people and caused $358 million in damage. Tuesday's quake produced about 500 times less energy than the 1987 temblor.
The Puente Hills thrust is a slow-moving fault and is less likely to have major earthquakes than, say, the San Andreas fault. But major temblors can happen on slow-moving faults, Hauksson said, which is what happened in the 7.9 quake that struck China in 2008, killing about 70,000 people.
Earthquakes with a magnitude of 4 are quite common in Southern California, occurring every month or two, said Caltech seismologist Kate Hutton.
The last magnitude 4 quake occurred Saturday in northern San Diego County.
Tuesday's quake was a reminder of the tectonic forces that have been shaping the region for 3 million to 4 million years. The quakes are triggered as the Pacific plate moves northwest, shifting against the North American plate.