Earthquake · automatic estimate, may change
M 3.3ml
Earthquake near Fortuna, CA
Yes. A magnitude 3.3 earthquake was recorded 40 km (25 mi) south of Fortuna, CA, at 6:43 pm PDT on 21 October 2026 (01:43 UTC), 11 km deep. 10 people have reported feeling it to USGS. The magnitude and location are an automatic first estimate and may change.
USGS: 14 km SE of Petrolia, CA
- When
- 6:43 pm PDT on 21 October 2026 ()
- Where
- 40 km (25 mi) south of Fortuna, CA · earthquakes near Fortuna
- Magnitude
- M 3.3 (ml)
- Depth
- 11 km below the surface
- Felt
- 10 reports · strongest reported intensity III
- Nearest
- Humboldt County, 56 km NNE
- Nearest mapped fault
- San Andreas fault, 10 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 15 hours ago
Earthquake alerts for Fortuna, CA
Get a notification in this browser when USGS records an earthquake near Fortuna, CA. No account or email needed.
Alerts are on for .
Not a warning. An alert comes after USGS publishes a quake, usually minutes after the shaking. For early warning use ShakeAlert, through your phone's Wireless Emergency Alerts or the MyShake app.
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 48 km (30 mi) from the epicentre. In Fortuna, 40 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.
Likely felt in: Rio Dell 30 km, intensity II · Redway 32 km, intensity II · Hydesville 35 km, intensity II · Ferndale 39 km, intensity II · Fortuna 40 km, intensity II. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 1.1 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.3 would have released about 32 times as much.
- Northridge, California 1994 M 6.7 150,000× the energy of this one
- Mineral, Virginia 2011 M 5.8 6,700× the energy of this one
- Magna, Utah 2020 M 5.7 4,700× the energy of this one
- This earthquake M 3.3 about 1.1 tons of TNT
- Around the size people start to feel M 3.0 this one released 2.4× 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 6.4 on 2022-12-20 — about 53,000 times the energy of this one.
Before 2016, the USGS record lists 30 earthquakes of M5 or more within 50 km; the five largest:
- 7.2 The 1992 Petrolia, California Earthquake · 12 km NNW of this epicentre
- 6.6 32 km SW of Ferndale, California · 37 km WNW of this epicentre
- 6.5 30 km WSW of Ferndale, California · 40 km WNW of this epicentre
- 6.0 Near Rio Dell, California · 30 km N of this epicentre
- 6.0 53 km SW of Ferndale, California · 46 km W 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 40.2345, -124.1708. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Humboldt County, CA | 56 km (35 mi) | NNE | earthquakes near Humboldt County |
| Trinity County, CA | 101 km (62 mi) | ENE | earthquakes near Trinity County |
| Mendocino County, CA | 109 km (68 mi) | SE | earthquakes near Mendocino County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
7 earthquakes have been recorded within 50 km since this one.
- 1.7 16 km SE of Petrolia, CA
- 1.5 15 km SE of Petrolia, CA
- 2.1 30 km WSW of Petrolia, CA
- 1.5 14 km SE of Petrolia, CA
- 1.1 14 km SE of Petrolia, CA
- 1.8 13 km SE of Petrolia, CA
- 1.7 14 km SE of Petrolia, CA
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.
Revisions
USGS refines a solution as more stations report. Every change we have seen is listed here.
| What changed | From | To | When |
|---|---|---|---|
| felt reports | 9 | 10 | |
| felt reports | 8 | 9 | |
| reported intensity | 3.1 | 3.4 | |
| felt reports | 7 | 8 | |
| felt reports | 6 | 7 | |
| reported intensity | 2 | 3.1 | |
| felt reports | 1 | 6 | |
| reported intensity | not reported | 2 | |
| felt reports | not reported | 1 |
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.