Earthquake · automatic estimate, may change
M 3.4ml
Earthquake near Rio Dell, CA
Yes. A magnitude 3.4 earthquake was recorded 50 km (31 mi) WSW of Rio Dell, CA, at 8:21 am PDT on 12 October 2026 (15:21 UTC), less than 1 km deep. No felt reports to USGS yet. The magnitude and location are an automatic first estimate and may change.
USGS: 29 km W of Petrolia, CA
- When
- 8:21 am PDT on 12 October 2026 ()
- Where
- 50 km (31 mi) WSW of Rio Dell, CA · earthquakes near Rio Dell
- Magnitude
- M 3.4 (ml)
- Depth
- 0.7 km below the surface
- Felt
- no reports yet
- Nearest
- Humboldt County, 75 km NE
- Nearest mapped fault
- Mattole Canyon fault, 16 km from its surface trace — near is not the same as on
- Status
- Automatic — a machine’s first estimate, which may change
USGS · last changed by USGS · we first saw it 2 hours ago
This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.
At this magnitude and depth, people at rest would likely notice it out to about 59 km (37 mi) from the epicentre. In Rio Dell, 50 km away, the estimate is intensity II (weak). 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 2.1 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.4 would have released about 32 times as much.
- Northridge, California 1994 M 6.7 80,000× the energy of this one
- Mineral, Virginia 2011 M 5.8 3,600× the energy of this one
- Magna, Utah 2020 M 5.7 2,500× the energy of this one
- This earthquake M 3.4 about 2.1 tons of TNT
- Around the size people start to feel M 3.0 this one released 4.4× more
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 230,000 times the energy of this one.
Before 2016, the USGS record lists 41 earthquakes of M5 or more within 50 km; the five largest:
- 7.2 The 1992 Petrolia, California Earthquake · 34 km E of this epicentre
- 6.6 32 km SW of Ferndale, California · 12 km NNE of this epicentre
- 6.5 30 km WSW of Ferndale, California · 17 km NNE of this epicentre
- 6.5 The 2010 Eureka, California Earthquake · 41 km N of this epicentre
- 6.0 Near Rio Dell, California · 43 km ENE of this epicentre
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
Epicentre 40.2890, -124.6248. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Humboldt County, CA | 75 km (47 mi) | NE | earthquakes near Humboldt County |
| Mendocino County, CA | 139 km (86 mi) | SE | earthquakes near Mendocino County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
No further 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 . 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.