The magnitude-3.3 quake was centered in Beverly Hills at 3:26 a.m.
There are no immediate reports of damage.
Beverly Hills police watch commander Sgt. Michael Publicker said his station has been getting numerous calls from anxious citizens. He said, "Every alarm in the city is going off." But he added that his patrol officers had seen no signs of structural damage.
An officer at the nearby West Los Angeles police precinct said there had been no calls about the quake.
The Los Angeles Fire Department says its survey found no significant damage, injury or loss of life in the city.