PALM SPRINGS, Calif. — A 7.1 magnitude earthquake was felt across Southern California on Friday night, just a day after a 6.4 temblor struck near Ridgecrest.

The quake at 8:20 p.m. PDT was centered 11 miles from Ridgecrest, a Mojave Desert town 150 miles away from Los Angeles. The quake sent rocks crashing down parts of a state highway, ruptured gas lines and cut power to the town of Trona and parts of Ridgecrest, which saw building damage, fires and several injuries from the earlier quake.

California Gov. Gavin Newsom requested federal emergency assistance and officials reported "significant" damage and said they expected to have a better grasp of the earthquake's impact after daybreak.

Some residents of Ridgecrest, a town of about 28,000, were too fearful to sleep inside their homes, choosing instead to spend the night on their driveway or sidewalks, said Ridgecrest's Mayor Peggy Breeden.

Aftershocks, especially after an earthquake of this magnitude, are expected, said Ken Hudnt, a geophysicist with the U.S. Geological Survey.

Lucy Jones, a seismologist with the California Institute of Technology’s seismology lab, tweeted that the quake was part of the sequence that produced the earlier quake.

Jones warned in a news conference that she expects more earthquakes throughout the night.

"A magnitude 7 usually has aftershocks that last for years," she said. "My expectation is that Ridgecrest is having a pretty difficult time. It is a foreshock, when an aftershock becomes bigger than a main shock we change the name to a foreshock."

If the preliminary magnitude is correct, it would be the largest Southern California quake in 20 years.

Caltrans officials were still surveying bridges and roads, but did say State Route 178 near Kern River Canyon was closed because of a rockslide.

The quake was felt in downtown Los Angeles as a rolling motion that seemed to last at least a half-minute. It was felt as far away as Las Vegas, and the USGS says it also was felt in Mexico.

Three minutes before the 7.1 quake, a 5.0-magnitude quake was centered close by – 9 miles west-southwest of Searles Valley.

In the Yucca Valley area, Republican state Assemblyman Chad Mayes tweeted a photo of items on the floor of a Walmart store.

At the Dodgers home game against the Padres, the quake interrupted the bottom of the fourth inning. But they played on as if nothing was amiss.

In Ridgecrest, people were reporting major structural damage, particularly at the Naval Air Weapons Station — China Lake.

The day before, a 6.4-magnitude earthquake also centered near Ridgecrest caused structural damage and injuries near the epicenter, and rattled nerves across Southern California and into Nevada on the Fourth of July holiday.

The two quakes are considered two of the most intense temblors to hit Southern California since 1994's Northridge quake.

Kern County Fire Chief David Witt said emergency officials in Ridgecrest responded to at least two house fires after the Fourth of July quake, a small vegetation fire, downed power lines and gas leaks.

"There are more calls than we have people," Witt said, adding that he expects local officials would get reinforcement. Minor injuries and some structural damage, including buildings with the glass blown out as well as downed grocery store shelves, were reported according to Witt.

Contributing: Associated Press