An earthquake that lightly jiggled San Diego and Orange counties early Tuesday measured 3.6 on the Richter scale and was one of hundreds of aftershocks centered off Oceanside since a larger quake emanated from an offshore fault there in 1986, authorities said.
Officials reported no damage or injuries from the 1:03 a.m. temblor. Seismologists at the California Institute of Technology in Pasadena placed the quake epicenter at 28 miles southwest of Oceanside in the Pacific Ocean.
"A quake of that scale causes no damage even if you're right on top of it," said Duncan Agnew, a geophysicist with the Scripps Institution of Oceanography.
A Caltech spokesman said Tuesday's tremor was an aftershock from an earthquake measuring 5.3 on the Richter scale that hit the same area July 13, 1986, causing more than $700,000 damage.
This most recent temblor is among hundreds of aftershocks from the 1986 earthquake that have rumbled along the San Diego Trough fault line that runs from Baja California to Santa Catalina Island, said Egill Hauksson, a geophysicist at USC.