The epicenter is near Ridgercrest, a city in Kern County which is located 272 km north of Los Angeles downtown. A nearby area was hit by a magnitude 6.4 earthquake on July 4.
According to Kern County officials, the county has activated the emergency operations center. There are roughly 1,800 people without power following the 7.1-magnitude earthquake, but there are currently no reports of major gas leaks, major building collapse and no fatalities immediately reported.
David Witt, chief of Kern County Fire Department, said the department received many phone calls for help, and is responding to them for service and ordering additional resources.
Authorities are concerned about dam damage, building collapse and people trapped, he said, adding currently they are going all out to gather information.
Mayor of Los Angeles Eric Garcetti said there are no reports of serious damage in Los Angeles related to the earthquake Friday night.
"We are sending an Urban Search and Rescue Task Force Team to Kern County to help with the damage closer to the epicenter," he tweeted.
The Los Angeles Fire Department has been dispatching vehicles and helicopters around the city to identify any damage or emergency needs, said Brian Humphrey of the department.
"This is part of the same sequence," said Lucy Jones, a seismologist from California Institute of Technology, referring to the quake and the other one in Searles Valley on July 4, at a press conference which was held 45 minutes after Friday's quake.
She explained that usually, the aftershock would not be stronger, but about 5 percent of the major quakes might be followed by something even bigger.
"Smaller quakes - M5s are likely and a M6 is quite possible," she tweeted after the quake.
According to USGS forecast, over the next week, there is a 9-percent chance of one or more aftershocks that could be larger than magnitude 7.1. It is likely that there will be smaller earthquakes over the next week.
The number of aftershocks will decrease over time, but a large aftershock can increase the numbers again, temporarily, said the USGS.
The last time southern California saw a major quake was in 1999, when a magnitude 7.1 quake jolted the state in the Hector Mines area of the Mojave Desert. No major damage or injuries occurred because of its distance from Los Angeles.
