Mendocino County Experiences Multiple Earthquakes, Strongest at 3.9 Magnitude, No Damage Reported

USGS indicated there was a prior magnitude-3.9 earthquake near Covelo before the 3:05 p.m. sequence, signaling multiple sizable shocks in a short window.
The 3.9 tremors were centered roughly 7 miles north-northeast of Covelo, with depths reported around 6.8 miles (about 11 km) in at least one update, and about 7.1 miles NNE in another listing.
A separate preliminary magnitude-3.6 earthquake occurred at 3:05 p.m., about 11 kilometers north-northeast of Covelo, with reports of light shaking and some residents receiving warnings.
Another tremor followed at 3:33 p.m. measuring magnitude 2.7, about 7 miles north-northeast of Covelo, with a depth around 4 miles.
Officials repeatedly emphasized standard earthquake safety guidance, including the drop, cover, and hold on technique, with situation-specific tips for indoors, outdoors, vehicles, and even wheelchair users, plus reminders to crawl under a sturdy table if possible when shelter isn’t available.
A rapid cluster of earthquakes struck near Covelo in Mendocino County on Friday afternoon, July 10, with the strongest event reaching magnitude 4.4, according to Kym Kemp. The largest quake was centered about 11 kilometers north of Covelo at a depth of 10.7 kilometers. No injuries or damage were reported.
The sequence unfolded quickly. Multiple quakes hit in close succession, including a 4.2 magnitude event at 6:14 p.m. and several smaller tremors earlier in the afternoon. KCRA confirmed the 4.2 magnitude quake had a depth of about 10 miles. Residents across the region felt light shaking.
The swarm began Friday afternoon north of Covelo. Kym Kemp reported that the largest quake measured magnitude 4.4, followed by three smaller events before a 4.2 magnitude quake struck at 6:14 p.m. The epicenter sat about 11 kilometers north of Covelo, with a depth of 10.7 kilometers. Depths ranged across the sequence, with some shallower events also recorded.
Sacramento Bee reported the 4.2 magnitude quake shook the region at a depth of about 7 miles, with its epicenter roughly 7 miles from Covelo. A caller to KCRA described feeling the shaking directly. This kind of clustering — several quakes in a short window — points to swarm activity rather than one isolated event.
Depth matters a lot in earthquakes. Shallower quakes send more energy to the surface, making shaking feel stronger near the epicenter. In this sequence, depths ranged from about 4 miles for smaller tremors to nearly 11 kilometers for the largest events. That variation helped shape how strongly different areas felt the ground move.
San Luis Obispo Tribune noted the 4.2 quake struck at a depth of 7 miles with its epicenter about 7 miles from Covelo. Magnitudes between 2.5 and 4.4 are typically felt by people but rarely cause structural damage. That held true here — residents felt shaking, but no damage was reported across the affected area.
Despite the rapid series of quakes, officials confirmed no injuries or property damage. Some residents received alerts during or just before the events. The USGS urged anyone who felt the shaking to submit a report through its Did You Feel It system, which helps scientists map how shaking spreads across a region.
Authorities reminded the public of standard earthquake safety steps. The key advice: drop, take cover, and hold on. If indoors, get under a sturdy table. If outside, move away from buildings and power lines. The guidance applies whether someone is in a car, on foot, or uses a wheelchair. The message was consistent — stay low and protect your head.
Mendocino County sees frequent seismic activity. The region sits near the Mendocino Triple Junction, where three tectonic plates meet. That makes it one of the most seismically complex zones on the West Coast. Small to moderate quakes are common there, and swarms like Friday's are not unusual for the area.
KCRA noted a caller reported feeling the shaking from the 4.2 quake firsthand. Kym Kemp provided the most detailed account of the full sequence, describing the 4.4 as the largest in a series of at least four events. With no damage confirmed, emergency officials were monitoring the area but had not issued any escalated warnings as of Friday evening.
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