The U.S. Geological Survey said the quake struck at 7:14 a.m. local time about 2 miles (3 km) east-northeast of the San Bernardino County community of Loma Linda.
The epicenter was placed at a depth of 6 miles (10 km) by the California Institute of Technology.
Institute seismologist Kate Hutton told reporters that “it was felt pretty much throughout the Inland Empire," referring to the fast-growing region east of Los Angeles that includes San Bernardino and Riverside counties.
Monday morning’s tremor was preceded by a pair of 2.6 magnitude foreshocks that went unnoticed by the public.
