3.1-magnitude quake in Southern California felt near San Diego, geologists say
A 3.1-magnitude earthquake shook Southern California on Friday, the U.S. Geological Survey reported.
The quake struck near Julian just before 11 a.m., USGS reported. Light shaking could be felt about an hour away in San Diego.
People as far as Hemet and Cathedral City also may have felt some light shaking from the 4.2-mile deep earthquake, according to USGS.
Magnitude measures the energy released at the source of the earthquake, the U.S. Geological Survey says. It replaces the old Richter scale.
Quakes between 2.5 and 5.4 magnitude are often felt but rarely cause much damage, according to Michigan Tech.