The quake occurred at 4:49 a.m. at a depth of 8 miles, the USGS said. Its epicenter was located 8 miles north of Cabazon and 20 miles northwest of Palm Springs.
Residents reported feeling the temblor in San Bernardino, Banning, Lake Elsinore and Colton - as well as such far-flung areas as Woodland Hills and Laguna Niguel.
There were no immediate reports of injuries or damage.
DEVELOPING: More details will be added to this report as they become available.