The earthquake off the coast of San Francisco del Mar, in Mexico, registered a magnitude of 4.3, according to the US Geological Survey (USGS).
It struck at 3.32am PST (11.32am GMT), just over an hour after San Diego was hit by a 4.1 magnitude quake.
The shock, at 2.09am PST (10.09am GMT), had an epicentre 3 miles (5km) north east of Trabuco Canyon in California.
The Mexican quake was 54 miles (87km) south of the coast and at 22 miles deep (35km).
Both tremors came just days after the massive earthquake hit Alaska and triggered warnings of a tsunami hitting Canada, Hawaii and much of west coast America.
No tsunami warning was issued after the Mexican undersea tremor.
Earthquakenewstoday.com wrote: “Earthquakes of four to five magnitudes are often felt, but only causes minor damage.
“There are an estimated 13,000 light quakes in the world each year.
“In the past 24 hours, there have been one, in the last ten days two, in the past 30 days eight and in the last 365 days four hundred and fifteen earthquakes of magnitude 3.0 or greater that was reported nearby.”
During the earlier California quake, shaking was felt as far away as Los Angeles with people taking to Twitter to report their fears.
WSPA-TV Daybreak anchor Fred Cunningham tweeted: “4.0 magnitude earthquake waking up people early in Southern California. Centered near Trabuco Canyon.”
Andre Samuel posted: “Finally felt my first #earthquake , so that officially makes me a California Resident.”
California experiences several earthquakes each year, but geologists say it is long over due a major “Big One” of magnitide 8 or more along the San Andreas fault line.