A magnitude-4.2 earthquake struck near Castaic on Saturday night, about 20 minutes after a magnitude-3.0 quake hit the same area, the U.S. Geological Survey said.
The second and more powerful temblor happened at 7:18 p.m, and was initially reported at a magnitude of 4.5, according to the USGS. Its epicenter, in northwest Los Angeles County, was located 13 miles north-northwest of Santa Clarita and 19 miles northeast of Fillmore. The quake had a depth of 5 miles.
There were no immediate reports of injuries or damage.
Residents reported feeling the earthquake in Valencia, Hollywood, Simi Valley and Sylmar.
Dr. Lucy Jones, a USGS seismologist, described the 4.2 quake as "normal activity" for Southern California, and noted that the area where it took place has experienced "plenty" of earthquakes in the past.
Eight earthquakes of magnitude-4.2 or higher were recorded in Southern California in 2014, Jones said.
On Saturday night, the first, more shallow quake occurred at 6:58 p.m., according to the USGS. Its depth was recorded at 1.3 miles.
That earthquake's epicenter was located 9 miles north of Castaic and 24 miles west of Quartz Hill, the Geological Survey said. People reported feeling the temblor in Hollywood and East Los Angeles.
In a tweet, the Los Angeles Fire Department said it was "monitoring #CastaicQuake" but was not in "earthquake mode."
Also on Twitter, the Los Angeles County Fire Department reminded residents not to call 911 to ask if a quake had occurred: "Keep lines open for emergencies."