“It’s the first one we’ve had in a populated area for quite a long time,” said Kate Hutton, a seismologist at the California Institute of Technology in Pasadena reports the Associated Press in the San Francisco Chronicle.
While it was not the dreaded “Big One,” Hutton said: “It’s a drill for the ‘Big One’ that will be coming some day.”
The temblor struck shortly before midday and was centered nearly 9 miles deep in the rolling hills 30 miles east of Los Angeles. Scientists said there was a small chance — 5 percent — that the quake foreshadowed a larger event, but the risk diminishes with time.
The fault where the quake occurred took two to three seconds to break, Hutton said. Although it was widely felt, it was far less powerful than the magnitude-6.7 Northridge quake that toppled bridges and buildings, releasing about 1 percent of the energy of the 1994 shock.
It’ll be several days before scientists can pinpoint the exact fault, but this much is known. It occurred in a geologically unusual region where three faults meet on the north end of one of the state’s largest faults, the Elsinore fault, said James Dolan, a professor of earth sciences at the University of Southern California.
The quake caused minor damage and injuries — not a surprise to engineers who say ground shaking from a magnitude-5.4 rarely causes widespread destruction in a place like Southern California, which is built to withstand temblors that size.
Southern California was regularly rocked by moderate-sized earthquakes between 1987 and 1994, culminating in the Northridge disaster. Although the magnitude-7.1 Hector Mine quake hit a remote part of the Mojave Desert in 1999, the region has felt fewer moderate quakes compared to the years before Northridge.
Read it here: Scientists: Calif. quake not the `Big One’