Earthquake · reviewed by a seismologist
M 2.8md
Earthquake near Fortuna, CA
No earthquake was likely felt in Fortuna in the 24 hours to 11:42 pm PST (07:42 UTC). The last one was M 5.0, 123 km (76 mi) W, at 8:56 pm PST on 4 November 2026, estimated intensity II (weak) in town; 145 felt reports to USGS. Every earthquake near Fortuna
This page: a magnitude 2.8 earthquake was recorded in Fortuna, CA, at 2:48 am PST on 20 December 2022 (10:48 UTC), 22 km deep.
USGS: 2km E of Fortuna, CA
- When
- 2:48 am PST on 20 December 2022 ()
- Where
- in Fortuna, CA · earthquakes near Fortuna
- Magnitude
- M 2.8 (md)
- Depth
- 22 km below the surface
- Felt
- no reports yet
- Nearest
- Humboldt County, 21 km NE
- Nearest mapped fault
- Little Salmon fault, under 1 km from its surface trace — near is not the same as on
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 1352 days ago
Earthquake alerts for Fortuna, CA
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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 18 km (11 mi) from the epicentre. 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: Fortuna in town, intensity II · Ferndale 11 km, intensity II · Rio Dell 11 km, intensity II · Humboldt Hill 15 km, intensity II. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 490 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.8 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 31,000× the energy of this one
- Magna, Utah 2020 M 5.7 22,000× the energy of this one
- Around the size people start to feel M 3.0 1.9× the energy of this one
- This earthquake M 2.8 about 490 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 6.4 on 2022-12-20 — about 240,000 times the energy of this one.
Before 2016, the USGS record lists 35 earthquakes of M5 or more within 50 km; the five largest:
- 7.2 The 1992 Petrolia, California Earthquake · 31 km SSW of this epicentre
- 6.6 32 km SW of Ferndale, California · 43 km SW of this epicentre
- 6.5 The 1932 Eureka, California Earthquake · 19 km NW of this epicentre
- 6.5 30 km WSW of Ferndale, California · 41 km WSW of this epicentre
- 6.5 The 2010 Eureka, California Earthquake · 47 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 40.6000, -124.1355. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Humboldt County, CA | 21 km (13 mi) | NE | earthquakes near Humboldt County |
| Trinity County, CA | 86 km (54 mi) | E | earthquakes near Trinity County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
60 earthquakes have been recorded within 50 km since this one.
- 2.4 9km WSW of Ferndale, CA
- 2.1 7km SW of Ferndale, CA
- 1.8 9km SW of Ferndale, CA
- 2.1 3km ESE of Fortuna, CA
- 2.5 4km WNW of Fortuna, CA
- 1.7 4km WSW of Ferndale, CA
- 2.1 12km WSW of Ferndale, CA
- 1.8 16km WSW of Ferndale, CA
- 2.1 13km WSW of Ferndale, CA
- 2.1 16km WSW of Ferndale, CA
- 2.4 4km SE of Fortuna, CA
- 2.5 21km WSW of Ferndale, CA
- 2.0 5km SSW of Ferndale, CA
- 3.0 5km E of Fortuna, CA
- 2.6 6km SW of Ferndale, 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.
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.