Petrolia, California – A moderate offshore earthquake was recorded early Thursday morning off the Northern California coastline.
A magnitude 4.7 earthquake struck approximately 112 kilometers (about 70 miles) west of Petrolia early Thursday, according to the U.S. Geological Survey. The quake occurred at 4:49 a.m. local time and originated at a shallow depth of about 2.5 kilometers beneath the ocean floor.
The epicenter was located offshore of Humboldt County, west of California’s North Coast and several miles beyond the coastal stretch near Highway 1. Due to its offshore location, shaking on land was limited, and no immediate reports of damage or injuries were reported as of Thursday morning.
USGS data shows the earthquake was part of a broader zone of offshore seismic activity common along the complex tectonic boundary where the Pacific and North American plates interact. The region frequently experiences small to moderate earthquakes, many of which occur beneath the ocean and go largely unnoticed inland.
Residents in parts of coastal Northern California may have felt light shaking, particularly in rural areas near Petrolia, Ferndale, and remote stretches of the Lost Coast. Some early-morning residents reported brief rumbling sensations, though intensity appeared weak due to the distance from shore.
Officials have not issued tsunami warnings or advisories in connection with the quake, and the National Tsunami Warning Center indicated there was no tsunami threat from this event.
The USGS continues to monitor the area for aftershocks, which are possible following offshore earthquakes but are not guaranteed. Earthquake magnitudes and locations may be revised as additional seismic data is analyzed.
This event may be of interest to early-morning commuters, coastal residents, and offshore maritime traffic operating near the Northern California coastline.
Residents are encouraged to review earthquake preparedness plans and report any shaking through the USGS “Did You Feel It?” system to assist with data collection.
