U.S. Geological Survey said the moderate earthquake struck a desert area around 60 miles northeast of San Diego and 30 miles south of Palm Springs at 1:05 a.m. local time (4:05 a.m. ET).
The quake, which struck at a depth of less than 1 mile, was followed by three nearby aftershocks over the next three minutes measuring between magnitude 2.8 and 3.5, according to the USGS. Another two aftershocks of similar magnitudes were recorded over the next 40 minutes.