Earthquake · reviewed by a seismologist
M 1.8md
Earthquake near Fortuna, CA
No earthquake was likely felt in Fortuna in the 24 hours to 1:34 am PST (09:34 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 1.8 earthquake was recorded 41 km (25 mi) south of Fortuna, CA, at 6:23 am PST on 17 December 2019 (14:23 UTC), 13 km deep.
USGS: 16km SE of Petrolia, CA
- When
- 6:23 am PST on 17 December 2019 ()
- Where
- 41 km (25 mi) south of Fortuna, CA · earthquakes near Fortuna
- Magnitude
- M 1.8 (md)
- Depth
- 13 km below the surface
- Felt
- no reports yet
- Nearest
- Humboldt County, 56 km NNE
- Nearest mapped fault
- San Andreas fault, 11 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 2511 days 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 minor earthquake. Quakes this small are rarely felt and do not cause damage.
At this magnitude and depth, people at rest would likely notice it out to about 4 km (2 mi) from the epicentre. In Fortuna, 41 km away, the estimate is intensity I (not felt). 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.
Earthquakes near other towns within 30 km: Redway, Rio Dell.
How big was it?
This earthquake released about 13 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 1,100,000× the energy of this one
- Magna, Utah 2020 M 5.7 810,000× the energy of this one
- Around the size people start to feel M 3.0 72× the energy of this one
- This earthquake M 1.8 about 13 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 5.6 on 2019-06-23 — about 540,000 times the energy of this one.
Before 2016, the USGS record lists 27 earthquakes of M5 or more within 50 km; the five largest:
- 7.2 The 1992 Petrolia, California Earthquake · 14 km NNW of this epicentre
- 6.6 32 km SW of Ferndale, California · 39 km WNW of this epicentre
- 6.5 30 km WSW of Ferndale, California · 42 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 · 48 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 40.2322, -124.1422. 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 | 98 km (61 mi) | ENE | earthquakes near Trinity County |
| Mendocino County, CA | 107 km (67 mi) | SE | earthquakes near Mendocino County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
57 earthquakes have been recorded within 50 km since this one.
- 2.4 11km WNW of Ferndale, CA
- 2.2 4km WNW of Redway, CA
- 2.1 3km W of Petrolia, CA
- 1.9 14km W of Petrolia, CA
- 2.7 28km W of Petrolia, CA
- 4.3 33km W of Petrolia, CA
- 2.5 33km W of Petrolia, CA
- 1.6 8km WSW of Petrolia, CA
- 1.7 15km SE of Rio Dell, CA
- 2.0 14km W of Ferndale, CA
- 1.9 7km N of Petrolia, CA
- 2.1 8km SW of Petrolia, CA
- 2.1 4km N of Redway, CA
- 1.8 6km W of Petrolia, CA
- 1.9 4km WNW 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.
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.