A magnitude 4 earthquake struck Southern California early Sunday morning, marking the strongest tremor in a series of smaller earthquakes near Ontario International Airport over the past month. The quake occurred at 3:51 a.m. and was the fifth to register at a magnitude of 3 or higher in Ontario since early September, according to the U.S. Geological Survey.
The USGS reported that “moderate” shaking was felt near the epicenter, which can awaken many people. “Weak” or “light” shaking likely reached a wider area, affecting significant portions of San Bernardino and Riverside counties, as well as large parts of Los Angeles, Orange, and even San Diego counties.
Residents from Palmdale to San Diego reported feeling the quake. The USGS encouraged the public to share their experiences on its Did You Feel It? website.
Prior to Sunday’s event, the strongest earthquake recorded in the last month in San Bernardino County was a magnitude 3.9 quake on September 7, which caused “light” shaking that was sufficient to rattle windows and disturb parked vehicles.
The epicenter of Sunday’s earthquake was located approximately one-third of a mile southeast of the intersection of the 60 Freeway and Archibald Avenue, about 500 feet south of Mountain View Elementary School and half a mile east of Whispering Lakes Golf Course.
The USGS also indicated that its ShakeAlert earthquake early warning system was activated. Residents can download the earthquake early warning app for free at myshake.berkeley.edu.