San Diego Earthquake

A magnitude 4.0 earthquake struck off the coast of San Diego this morning. There were no immediate reports of damage or injuries. The quake struck 7:34 a.m. about 30 miles west of La Jolla and 37 miles west of San Diego, according to the U.S. Geological Survey. The quake originated about 12 miles underground, the USGS estimated.

The shaker was felt across San Diego County including Oceanside, Escondido, Vista and Carlsbad, as well as in Temecula, Laguna Niguel and Ladera Ranch. The USGS classified the quake as "light." That warning concerns the southernmost section of the San Andreas Fault and stems from new earthquake research being conducted by NASA and scientists from the Jet Propulsion Lab.

"There are very few earthquakes along this section of the fault," said Eric Fielding, a research scientist at JPL in Pasadena. "The fault has been locked and building up stress over the years. It could rupture at any moment." Fielding said this section of the fault has not produced a major earthquake in more than 300 years and is thought to be capable of a magnitude 8 event, as large as any known California earthquake.