The early morning earthquake was felt across the Inland Empire and as far away as Orange and Downey
Southern California residents across a wide stretch of the Inland Empire felt the ground move Wednesday morning when a 3.3-magnitude earthquake struck near Redlands, closely followed by a 3.2-magnitude aftershock less than a minute later. No injuries were reported, and no structural damage has been confirmed, but the back-to-back tremors served as another reminder of the seismic reality that defines daily life in one of the most geologically active regions in the United States.
What happened and where
According to the U.S. Geological Survey, the initial quake hit at approximately 9:45 a.m., with the epicenter sitting on the border of San Bernardino and Riverside counties, about 4 miles northwest of Loma Linda, at a shallow depth of just over two miles. The CBS News source placed the epicenter about 3.7 miles southwest of Redlands specifically, reflecting the proximity to both communities. Less than a minute after the first event, a 3.2-magnitude aftershock struck, rattling the same area before residents had fully processed the initial jolt.
The USGS “Did You Feel It?” reporting page collected accounts from people in Ontario, Perris, Orange and Downey — a geographic spread that underscores how the shallow depth of the quake allowed its energy to radiate outward more broadly than a deeper event of similar magnitude might have. The USGS Community Internet Intensity Map classified the shaking as light, meaning most people in the affected area would have felt noticeable movement but were unlikely to have encountered significant disruption, falling objects or property damage.
What the numbers actually mean
A 3.3-magnitude earthquake sits in the category that seismologists classify as minor. At this level, shaking is typically felt indoors — doors may rattle, hanging items may sway and unsecured objects on shelves may shift — but structural damage is rarely a concern. The magnitude scale is logarithmic, meaning a 4.0 event releases roughly 32 times more energy than a 3.3, and events above 6.0 carry thousands of times more destructive force than what struck near Redlands on Wednesday morning.
According to USGS data, California records several hundred magnitude 3.0 earthquakes per year, while only about 15 to 20 annually reach 4.0 or higher. In North America, only Alaska records more earthquakes per year than California. Historical data specific to the Redlands area shows the region averages approximately 31 magnitude 3.0 or greater earthquakes per year — roughly 2.6 per month. Wednesday’s sequence was notable but far from unusual for this corner of Southern California.
Why this area experiences frequent activity
The Redlands area lies within a corridor of Southern California where several fault systems converge. The region sits near the San Andreas Fault, the most extensively studied geological feature in North America, as well as a network of smaller, interconnected faults that run through the Inland Empire. The shallow depth of Wednesday’s quake — just over two miles below the surface — is characteristic of the area’s fault geometry and is a key reason why even modest events in this zone tend to be widely felt across communities far from the epicenter.
Aftershocks and what comes next
The rapid succession of the 3.2-magnitude aftershock is consistent with standard seismic behavior following a minor event. As surrounding rock adjusts to the stress redistribution caused by the main quake, smaller follow-on events typically occur. Additional smaller aftershocks followed throughout the day, with a 1.9-magnitude event recorded in the same area later Wednesday. Seismologists caution that no event can be definitively categorized as a main shock until the subsequent seismic pattern becomes clear over the following days.
Residents who felt the shaking are encouraged to check their homes for any displaced items and to revisit household earthquake preparedness plans, including securing heavy furniture, maintaining emergency water and food supplies and identifying safe shelter locations within their homes.
Sources: CBS News Los Angeles, ABC7 Los Angeles, USGS