A shallow 4.0‑magnitude tremor shook Northern California’s Lake County just after dawn on Wednesday.
Key points
- The earthquake registered a magnitude of 4.0, with its epicenter near Lake Pillsbury, six miles north of the lake.
- No injuries or major damage have been reported, and the quake was felt by a small number of people in the Mendocino National Forest area.
- USGS estimates a modest chance of aftershocks, with a 14% likelihood of a magnitude‑3 event and a 2% chance of another magnitude‑4 quake within a week.
Around 5 a.m. on Wednesday, a magnitude 4.0 earthquake was recorded near Lake Pillsbury in Lake County, Northern California, according to the U.S. Geological Survey (USGS) and reported by the New York Post (https://nypost.com/2026/10/28/us-news/magnitude-4-0-earthquake-strikes-lake-county-in-norcal/).
The quake’s epicenter was located about six miles north of Lake Pillsbury at a depth of roughly 6.5 miles. Initial readings listed the event at magnitude 3.9, but the USGS upgraded it to 4.0 shortly after the shaking began.
Location and magnitude
At least five people reported feeling the tremor in the USGS “Did You Feel It?” poll, with the strongest effects felt within the Mendocino National Forest, an area largely away from populated centers. No injuries or significant damage have been reported so far.
USGS officials noted a 14% probability of an aftershock of magnitude 3.0 or greater and a 2% chance of another quake of magnitude 4.0 or higher within the next week. The event is the most powerful in the region since a 4.8‑magnitude quake struck the ocean floor about 100 km west of Petrolia earlier this year.
Impact and response
Lake Pillsbury lies roughly 18 miles northeast of Potter Valley, and the recent tremor underscores the seismic activity that can occur in this part of the state, even when the epicenter is situated in largely forested, sparsely populated terrain.
Reader questions
What magnitude was the earthquake that struck Lake County?
The quake was measured at magnitude 4.0 after an initial reading of 3.9, according to USGS data.
Were there any injuries or significant damage reported?
No injuries have been reported, and there are no confirmed reports of major damage.
What is the likelihood of aftershocks following this event?
USGS gave the quake a 14% chance of an aftershock of at least magnitude 3 and a 2% chance of another magnitude 4.0 quake within the next week.
Source: nypost.com