There were no reports of injuries or structural damage in the immediate aftermath of the quake, which struck at 9:43 a.m. about 11 miles east of Hemet.
The earthquake's epicenter was located just over six miles southwest of Idyllwild, at a depth of 10 miles, according to the USGS.
"I heard it more than I felt it. It was pretty loud, here in San Jacinto," Gloria Avilez wrote on Facebook.
Julia Rosas said: "I'm in Banning didn't feel it." Nor did Rochelle Settle at UC Riverside or Melissa Bulthuis in West Hemet.
In a social media post, Steve Sibaja struck a somewhat ominous tone.
"The big one is coming soon never know when," Sibaja wrote.