Southern California experienced a double dose of seismic anxiety this week, with a moderate earthquake rattling the Inland Empire on Thursday morning, just a day after coastal communities were under a tsunami advisory triggered by a massive quake off the coast of Russia.
A preliminary 4.4-magnitude earthquake struck the Muscoy area of San Bernardino County at 9:32 a.m. on Thursday, July 31, 2025, according to the U.S. Geological Survey (USGS). The temblor, which occurred at a shallow depth of just over three miles, was followed minutes later by a smaller 3.1-magnitude aftershock in nearby Rialto. Shaking was felt across a wide swath of the region, from the Inland Empire to Los Angeles and Orange counties. Residents reported feeling a “rolling sensation” as far away as Garden Grove and Irvine. Fortunately, there were no immediate reports of significant damage or injuries from the event.
According to a report from the Los Angeles Times, an average of 25 earthquakes with magnitudes between 4.0 and 5.0 occur annually in California and Nevada, making Thursday’s event a relatively common, albeit noticeable, occurrence for the seismically active region.
This local tremor came just a day after the Southern California coastline was on alert due to a different kind of seismic threat. A powerful 8.8-magnitude earthquake that struck off the Pacific coast of Russia’s Kamchatka Peninsula on Tuesday, July 29, prompted the U.S. Tsunami Warning Center to issue alerts across the Pacific. While more severe tsunami warnings were issued for parts of Northern California, Hawaii, and Alaska, most of the Southern California coast was placed under a tsunami advisory overnight into Wednesday morning.
An advisory is the middle tier of the alert system, indicating that a tsunami capable of producing strong, dangerous currents or waves is expected, but widespread inundation is not. Authorities urged the public to stay away from beaches, harbors, and marinas as a precaution. The first waves, though small, were projected to reach the Los Angeles harbor around 1:05 a.m. on Wednesday.
As reported by ABC7, the threat subsided without incident, and the advisory for Southern California was lifted shortly after 6 a.m. on Wednesday, July 30. Los Angeles County officials subsequently announced the reopening of all county beaches, parking lots, and restrooms. In Hawaii, where a more serious warning had been in effect, the largest recorded wave was 5.7 feet, and evacuation orders were later lifted. The quake’s epicenter in Russia experienced more significant waves, reportedly reaching up to 13 feet.
These back-to-back events serve as a critical reminder for all Californians to be prepared for earthquakes and other natural disasters. Officials emphasize the importance of having an emergency plan and a well-stocked earthquake kit. Resources for creating a plan and building a kit are available from numerous agencies, including Ready.gov and the Federal Emergency Management Agency (FEMA). The City of Los Angeles also provides detailed resources for homeowners, families, and businesses through its earthquake preparedness website. Experts advise that being prepared can significantly reduce the impact of a disaster on individuals and families.
