There have been no immediate reports of casualties or damage. Local netizens have shared footage showing apartments in California affected by the powerful jolt.
At least 159 aftershocks of magnitude 2.5 or greater were recorded after the first earthquake, according to USGS. The earlier shaking intensity levels had been predicted for the area and were below damaging levels, hence an alert was not triggered, according to local media reports.
The USGS web site was temporarily unavailable Friday night. Local media suggested that the seismic agency's web site was overwhelmed with requests following the significant temblor.