Utilities including Southern California Edison and the Los Angeles Department of Water and Power said service was uninterrupted. Residents reported items falling off shelves and some said phone service was cut.
"We can't call out, but everything is OK here. We just hope everyone else is safe," San Fernando resident Leslie Satterthwaite said.
The quake struck at 6:26 p.m. Pacific time (9:26 EST), 2 miles northeast of the city of San Fernando, said Lucy Jones, a seismologist with the U.S. Geological Survey in Pasadena.
She said the quake was an independent or new quake, not an aftershock.
That quake was followed a minute later by a magnitude-2.8 aftershock centered six miles northeast of Lake View Terrace, a community just 4 miles southeast of San Fernando, said USGS seismologist Sue Hough.
The second, more powerful aftershock, occurred at 6:50 p.m. and was centered in the same location as the initial quake, seismologist said.
David Martinez, 22, of neighboring Sylmar, said his house phone went dead.
"I can't call out from my phone, but I could take incoming calls. I'm just trying to call family and friends to see if they are all right," Martinez said.
"It shook pretty hard," he said of the original quake. "Nothing fell off my walls, but my entertainment system shook back and forth a little bit. I'm going to take down everything off my walls, especially my frames."
A San Fernando police officer said they did not feel any shaking at the Police Department. The officer added there were no reports of injury or damage.
The temblor was felt in areas including downtown Los Angeles, Santa Monica, West Hollywood, Hollywood, Toluca Lake, Pasadena, Sun Valley, Woodland Hills, Sherman Oaks, and Northridge. Los Angeles County sheriff's deputies covering West Hollywood said they received queries about the quake.
Earlier in the day, a quake with a magnitude-3.6 struck in San Bernardino County at 9:40 a.m. about 37 miles northwest of Barstow, according to a report from the California Institute of Technology in Pasadena.
There were no reports of injury or damage, said a sheriff's dispatcher.
Barstow is about 115 miles northeast of downtown Los Angeles.