The quake occurred at 4:49 a.m. at a depth of 8 miles, the U.S Geological Survey said. Its epicenter was located in Riverside County, 6.8 miles north of Cabazon and 19.3 miles northwest of Palm Springs.
The magnitude was initially measured at 4.6 before being revised downward.
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.
"It seriously felt like somebody rear-ended me from behind," Lyft driver David Allison said in an interview in Banning. "The whole car shook -- like a very sharp jolt."
At least 27 aftershocks followed, the largest of which was a 3.2, the USGS said. The magnitude of the smaller quakes ranged from .5 to 2.2.
There were no reports of injuries.
M4.5 quake this morning occurred under San Bernardino Mtns. near a complex part of the San Andreas fault. It's just east of the 1986 North Palm Spring quake, a M5.9 that may have been on San Andreas. Fault cannot be clearly seen on the surface here. https://t.co/TV8wLxJVRO— Dr. Lucy Jones (@DrLucyJones) May 8, 2018
Renowned seismologist Dr. Lucy Jones said she slept through the earthquake, which was reportedly felt by more than 10,000 people throughout the region.
"Historically, the area around Mt. San Gorgonio is the only part of southern San Andreas fault that produces smaller quakes," Jones said on Twitter. "But the main San Andreas is not clearly defined here. At the surface, it disappears, covered by the Banning thrust fault."
At a morning press conference held at the Caltech Seismological Laboratory in Pasadena, experts said the probability of a larger earthquake increases for the following week after a temblor such as Tuesday's, but then those chances decrease over time. They added that the chances are about 1 to 2 percent, starting as early as later Tuesday afternoon.
The seismologists also said, however, that earthquakes in this magnitude range are seen in that San Andreas fault area, known as the San Gorgonio Knot, every couple of years.
"The last one we had was a 4.4 back in January of 2016, so this isn't unusual for this area," said seismologist Dr. Jennifer Andrews.
Meantime, the earthquake experts gave a thumbs up to ShakeAlert earthquake warning system. They said the warning arrived in the L.A. County area about 30 seconds before the strong-shaking waves hit.
In Riverside, the alarms went off about 8 seconds ahead of time and only 5 seconds ahead of time in Palm Springs.
As for a possible relation to the earthquakes and volcano activity in Hawaii, Caltech officials said there was no direct correlation.