A magnitude 3.4 earthquake occurred at 9:44 a.m. Saturday roughly 9 miles east-northeast of Borrego Springs, causing brief, light shaking that was felt in the northern part of San Diego County, according to the U.S. Geological Survey.
The temblor was followed by a 3.1 aftershock one minute later.
Geological Survey data indicates the earthquake occurred on or near the San Jacinto fault, a 130 mile-long strike-slip system that passes through parts of San Diego, Imperial, Riverside and San Bernardino counties. The San Jacinto is a worrisome fault; in April 1918 it produced a 6.8 earthquake that caused extensive damage in the towns of Hemet and San Jacinto.
Seismologists say that temblors the size of the one that occurred on Saturday rarely lead to far larger quakes.
