BIG BEAR CITY, Calif. – A magnitude-5.4 earthquake shook Southern California early Saturday, jarring residents awake as far south as San Diego and rattling buildings in downtown Los Angeles. There were no immediate reports of injuries or serious damage.

The quake hit at 4:19 a.m. about 4 miles north of Big Bear City, a mountain resort town 90 miles east of downtown Los Angeles. It was followed by a magnitude-4.5 one minute later, then a magnitude-4.2 and dozens of smaller aftershocks.

Attorney Steven De Salvo was working on a legal brief on the 15th floor of a downtown office building at the time.

“I’m tired, trying to stay awake, and this definitely jolted me awake,” De Salvo said. “The shades were kind of rocking back and forth, there was kind of a low rumble. The walls were vibrating. I’ve never been in a skyscraper in an earthquake before. It lasted I would say about 10 to 15 seconds.”

Seismologist Kate Hutton, at the California Institute of Technology seismology laboratory in Pasadena, said the main quake appeared to be a new earthquake sequence in an area well known for seismic activity.

She said there did not appear to be any link to the deadly 1992 Landers-Big Bear quakes, which have had more than 50,000 aftershocks. The magnitude-7.3 Landers quake on June 28, 1992, was followed a few hours later by a magnitude-6.5 quake in Big Bear area. The quakes killed one child, injured more than 400 people and caused nearly $100 million in damage.