A 3.6 magnitude earthquake struck Loma Linda on Tuesday, according to the United States Geological Survey.
The quake struck 12:18 p.m. near Loma Linda.
There were no immediate reports of damages.
Local news from across Southern California
People on Twitter and Facebook reported feeling the quake in the Inland Empire areas of Riverside, Moreno Valley and Colton.
Someone reported a "slight bump" in Yucaipa.
"Phew, thought I was going crazy. Definitely felt an earthquake but wasn't sure. News just talked about it now but it was small. 3.6," wrote Twitter user TahNizzle.
Twitter user Heidi33G wrote: "Earthquake just minutes ago 12:18 today it was scary quick shake but unexpected."
Facebook user Alan Llavore at first thought the earthquake was the wind, but "... more like I heard it than felt it ..."
Another Facebook user, Jessica Marquez said she felt it in Riverside.
"It lasted a while too," she wrote. "I was wondering if it was the big one cuz it just got stronger and stronger."
Aliza Bixby said she felt it in Indio/La Quinta: "House creaked a little."
Rosa Zamora said her kids got scared.
Adriana Katanic-Curiel, of Riverside, said she feld a "sudden jolt."
It caught her off guard as she was sitting at her computer.
"Not like the kind that you can hear coming and have time to mentally prepare for," she wrote. "I don't usually get scared, but this one startled me."