The first quake happened at 12:47 a.m. and began from a depth of 11 miles, the U.S. Geological Survey said.
The epicenter was 66 miles northeast of San Diego, the Los Angeles Times reported.
The second quake was centered near Santa Clarita, north of Los Angeles, at 8:24 a.m.
A week ago, a magnitude 3.5 earthquake was recorded at 1:40 p.m., 4 miles from Blue Lake, 208 miles east of Sacramento, the USGS said.
The Valle Vista quake Sunday happened 3 hours after a magnitude 7.7 quake struck off Canada's west coast, briefly triggering a tsunami warning in Hawaii.