Petrolia, California – A magnitude 4.3 earthquake struck 106 kilometers west-northwest of Petrolia early Sunday morning, briefly rattling nerves in coastal Northern California but causing no immediate damage.
According to the U.S. Geological Survey, the quake occurred at 6:50 a.m. PDT at a shallow depth of 2.8 kilometers beneath the Pacific Ocean. The tremor registered light intensity (ShakeMap II), with no felt reports submitted by residents as of 9 a.m.
The epicenter was located offshore in the seismically active Cascadia Subduction Zone, an area known for frequent undersea quakes. Humboldt and Del Norte counties remain structurally unaffected, and no tsunami warning was issued.
The USGS notes a 15% chance of a magnitude 3.0 or greater aftershock in the next seven days, but the risk of stronger seismic activity remains under 2%. Residents are advised to secure loose objects and review emergency plans as a precaution.
This morning’s event is a reminder of Northern California’s seismic volatility, though it poses no current threat to inland communities such as Eureka, Arcata, or Redding.
No advisories or alerts are currently active, but authorities recommend monitoring official channels for updates throughout the week.
