A magnitude 4 earthquake rattled Southern California earlier than daybreak Sunday morning — the strongest in a collection of modest earthquakes to strike close to the Ontario Worldwide Airport within the final month.

Sunday’s 3:51 a.m. earthquake was the fifth of magnitude 3 or greater detected in Ontario since early September, in accordance with the U.S. Geological Survey.

“Average” shaking was felt in areas closest to the epicenter, the USGS mentioned, as outlined by the Modified Mercalli Depth Scale. That’s robust sufficient to awaken many individuals. “Weak” or “mild” shaking could have been felt throughout a broad area, together with essentially the most populous parts of San Bernardino and Riverside counties, giant swaths of Los Angeles and Orange counties, and components of San Diego County.

Individuals reported feeling the earthquake from Palmdale to San Diego. The USGS requested folks to submit stories of what sort of shaking they could have felt — or didn’t really feel — on the company’s Did You Really feel It? web site.

Till Sunday, the strongest earthquake up to now month to hit San Bernardino County’s fourth most populous metropolis occurred on Sept. 7, when a magnitude 3.9 earthquake brought about “mild” shaking to be felt near the epicenter. Mild shaking is sufficient to disturb home windows and dishes and may rock standing vehicles noticeably.

The epicenter of Sunday’s earthquake was centered about one-third of a mile southeast of the place the 60 Freeway meets Archibald Avenue. That’s about 500 ft south of Mountain View Elementary College and half a mile east of the Whispering Lakes Golf Course.

The USGS mentioned that its ShakeAlert earthquake early warning system was activated. Individuals can obtain the earthquake early warning app at no cost at myshake.berkeley.edu.

Are you prepared for when the Large One hits? Prepare for the subsequent huge earthquake by signing up for our Unshaken publication, which breaks down emergency preparedness into bite-size steps over six weeks. Be taught extra about earthquake kits, which apps you want, Lucy Jones’ most essential recommendation and extra at latimes.com/Unshaken.