41 km W of Petrolia, CA

Yes. A magnitude 1.8 earthquake was recorded 41 km W of Petrolia, CA, at 9:29 am PDT on 11 October 2025 (16:29 UTC), 19 km deep. The magnitude and location are an automatic first estimate and may change.

2025-10-11 16:29 UTC · 19 km deep · released about 16 lb of TNT

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Distance rings around the epicentre, with the nearest towns at their true direction and later quakes as coloured dots. Not a shaking map — see the USGS ShakeMap for that.

When: 2025-10-11 16:29 UTC
Magnitude: M 1.8 (md)
Depth: 19 km below the surface
Felt: no reports yet
Nearest: Humboldt County, 86 km NE
Status: Automatic — a machine’s first estimate, which may change

USGS · last changed by USGS 397 days ago · we first saw it 397 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth it was probably too small to be felt, even directly above it. Estimated from magnitude, depth and distance with the intensity equation USGS Did You Feel It? uses; felt reports, where there are any, are the measurement.

How big was it?

This earthquake released about 16 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.

Mineral, Virginia 2011 M 5.8 970,000× the energy of this one
Magna, Utah 2020 M 5.7 680,000× the energy of this one
Around the size people start to feel M 3.0 61× the energy of this one
This earthquake M 1.8 about 16 lb of TNT

Energy from the Gutenberg–Richter relation (log₁₀E = 1.5M + 4.8), rounded to two figures; bar length is magnitude, which is already a logarithm of energy. Magnitudes of past earthquakes from the USGS catalogue.

For this area

The largest earthquake within 50 km since 2016 was M 7.0 on 2024-12-05 — about 61,000,000 times the energy of this one.

Before 2016, the USGS record lists 38 earthquakes of M5 or more within 50 km; the five largest:

7.2 The 1992 Petrolia, California Earthquake · 46 km E of this epicentre Apr 25, 1992
6.6 32 km SW of Ferndale, California · 22 km NE of this epicentre Apr 26, 1992
6.5 30 km WSW of Ferndale, California · 25 km NE of this epicentre Apr 26, 1992
6.5 The 2010 Eureka, California Earthquake · 43 km N of this epicentre Jan 10, 2010
6.0 Offshore Humboldt County, California · 36 km SSW of this epicentre Mar 19, 1910

Since 2016: the QuakeIndex catalogue (US, M1.5+), built from the USGS FDSN event service. Before 2016: USGS ComCat, M5+ from 1900. Distances are between epicentres. This is the record, not a forecast.

Where

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Nearby places

Place	Distance	Direction from the epicentre
Humboldt County, CA	86 km (53 mi)	NE	earthquakes near Humboldt County
Mendocino County, CA	146 km (91 mi)	SE	earthquakes near Mendocino County

Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.

Aftershocks so far

58 earthquakes have been recorded within 50 km since this one.

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 13:34 UTC. QuakeIndex does not forecast aftershocks. When USGS issues an operational aftershock forecast it appears on the USGS event page.

On USGS

The official USGS event page — the source of record for every value above
Did you feel it? Report it to USGS — reports go to USGS, not to us
ShakeMap for this event, when USGS has produced one

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.