Map of earthquake location today (Dec. 14, 2012) near southern California.
An earthquake of preliminary magnitude 6.3 struck today off the coast of Southern California, according to the U.S. Geological Survey (USGS).
The temblor's epicenter was 172 miles (277 km) southwest of Coronado, Calif., (just outside of downtown San Diego) and 163 miles (263 km) south-southwest of Santa Catalina Island. It originated 7 miles (11.3 km) deep and struck at 2:36 a.m. local time (1036 UTC), the USGS reports.
An aftershock of preliminary magnitude 4.7 followed 15 minutes later.