5.6 Earthquake Rocks Northern California, Region’s Strongest Since 1940
A magnitude 5.6 earthquake struck rural Mendocino County in Northern California on Wednesday morning, marking the strongest seismic event to hit the region in 86 years. While no deaths were reported, the quake caused some injuries, knocked out power to thousands of residents, and triggered hundreds of thousands of early warning alerts across the state.
The earthquake struck at 8:10 a.m. PT approximately 7 miles (12 km) northwest of Willits and about 7 miles north of Redwood Valley, according to the U.S. Geological Survey. Initially reported as a magnitude 6.0, the USGS later downgraded the reading to 5.6. The quake originated about 5 miles (8 km) below the Earth’s surface and lasted approximately 30 seconds.
Widespread Shaking and Immediate Impact
The shaking was felt across a vast swath of Northern California, including the Bay Area as far south as San Jose, according to ABC7 News. Residents described the experience as terrifying and unlike anything they had felt before.
“That was the biggest earthquake I have felt in my life. And I’ve lived in Ukiah for most of my 54 years,” Moneca Vargas at Saint Mary’s Catholic School in Ukiah told KTVU. “My whole house shook.”
Daniel Alonzo, another Ukiah resident, described the sensation to KTVU as “almost like a freight train was running right through our house.” He said the shaking was so severe it made him dizzy, as if he were on a roller coaster.
At its peak, approximately 10,000 PG&E customers lost power across the region. By 8:45 a.m., crews had restored power to about 2,000 customers, though roughly 8,000 remained without electricity, according to the Press Democrat. PG&E deployed crews to repair downed power lines reported in several locations.
Injuries and Damage Assessments
Heather Rose, a Mendocino County spokesperson, confirmed that hospitals had reported some injuries but declined to provide details on their nature or extent, the Associated Press reported. No deaths were confirmed.
Minor structural damage was reported across the region, including cracked foundations, broken water pipes, and fallen merchandise in local businesses. The Safeway in Willits was evacuated after broken water lines were discovered. Interim Willits City Manager James Connor told the Press Democrat that initial inspections found no damage to city infrastructure, though power lines were down in some locations.
State Sen. Mike McGuire, who represents District 2 including Mendocino County, reported that damage assessments found no major public infrastructure damage to hospitals, sewer systems, or water facilities in Ukiah and Willits.
Early Warning System Activated
California’s ShakeAlert system performed robustly, with the MyShake app sending approximately 657,000 early warning alerts throughout Northern California, according to the California Governor’s Office of Emergency Services. This represents one of the largest deployments of the early warning system for a single seismic event.
Governor Gavin Newsom was briefed on the earthquake and coordinated with emergency officials to assess impacts and damage, ABC7 reported.
Scientific Context
The earthquake occurred near the Maacama Fault, a major strike-slip fault that is the northward continuation of the Hayward-Rodgers Creek Fault system. UC Berkeley Seismology Lab research scientist Amy Williamson said this is the largest quake on this fault in 75 years, according to KTVU.
Veteran California seismologist Lucy Jones told the Associated Press that while the area experiences earthquakes regularly, they are usually smaller than this. “Aftershocks are likely, but they’ll probably stay on the low side,” she said. At least 12 aftershocks were recorded within hours of the main event, most under 2.5 magnitude.
The New York Post noted that the most recent magnitude 5.0-or-greater earthquake in California prior to this was a 5.1-magnitude quake on June 3, 2026, centered in the Pacific Ocean west of Humboldt County.
Looking Ahead
Seismologists expect aftershocks of up to magnitude 4.0 in the days following the main event. USGS physical scientist Robert Michael De Groot warned that “this is earthquake country and people should definitely be prepared for more shaking.” No tsunami warning was issued as the quake occurred inland.
As cleanup and damage assessments continue, the event serves as a reminder of Northern California’s seismic vulnerability and the importance of earthquake preparedness, even in regions not situated on major fault lines. The Maacama Fault, which produced Wednesday’s quake, accommodates roughly a quarter of the total slip motion between the Pacific and North American tectonic plates, underscoring the ongoing seismic activity beneath the region.
For residents like Janet Pauli, a rancher and Potter Valley Irrigation District vice president who described the quake to the Press Democrat as “one of the hardest single jolts I’ve felt,” the event was a stark reminder that even rural Northern California communities must remain vigilant. Willits Mayor Tom Allman captured the resilient spirit of the region, telling KTVU: “We’re through it. I’m feeling good.”