QuakeIndex

Earthquake · reviewed by a seismologist

M 3.3ml

Earthquake near Ferndale, CA

No earthquake was likely felt in Ferndale in the 24 hours to 2:49 am PST (10:49 UTC). The last one was M 5.0, 113 km (70 mi) W, at 8:56 pm PST on 4 November 2026, estimated intensity III (weak) in town; 145 felt reports to USGS. Every earthquake near Ferndale

This page: a magnitude 3.3 earthquake was recorded 8 km (5 mi) south of Ferndale, CA, at 3:41 pm PDT on 31 August 2022 (22:41 UTC), 26 km deep. 19 people have reported feeling it to USGS.

USGS: 8km S of Ferndale, CA

3:41 pm PDT, Aug 31, 2022 · · 26 km deep · released about 1.5 tons of TNT

Every earthquake near Ferndale Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Humboldt County 36 kmTrinity County 98 km
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
3:41 pm PDT on 31 August 2022 ()
Where
8 km (5 mi) south of Ferndale, CA · earthquakes near Ferndale
Magnitude
M 3.3 (ml)
Depth
26 km below the surface
Felt
19 reports · strongest reported intensity II
Measured shaking
intensity III (ShakeMap)
Nearest
Humboldt County, 36 km NE
Nearest mapped fault
Little Salmon fault, 15 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 1467 days 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 47 km (29 mi) from the epicentre. In Ferndale, 8 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: Ferndale 8 km, intensity II · Rio Dell 13 km, intensity II · Fortuna 13 km, intensity II · Humboldt Hill 25 km, intensity II · Eureka 34 km, intensity II · Bayside 41 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 1.5 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.

  1. Northridge, California 1994 M 6.7 110,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 5,100× the energy of this one
  3. Magna, Utah 2020 M 5.7 3,600× the energy of this one
  4. This earthquake M 3.3 about 1.5 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 3.1× 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 6.2 on 2021-12-20 — about 20,000 times the energy of this one.

Before 2016, the USGS record lists 37 earthquakes of M5 or more within 50 km; the five largest:

  1. 7.2 The 1992 Petrolia, California Earthquake · 19 km S of this epicentre
  2. 6.6 32 km SW of Ferndale, California · 29 km WSW of this epicentre
  3. 6.5 The 1932 Eureka, California Earthquake · 25 km N of this epicentre
  4. 6.5 30 km WSW of Ferndale, California · 27 km WSW of this epicentre
  5. 6.5 The 2010 Eureka, California Earthquake · 40 km WNW 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 40.5055, -124.2560. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Humboldt County, CA 36 km (22 mi) NE earthquakes near Humboldt County
Trinity County, CA 98 km (61 mi) E earthquakes near Trinity County
Mendocino County, CA 138 km (86 mi) SSE earthquakes near Mendocino County

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

Aftershocks so far

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

  1. 2.4 24km WSW of Ferndale, CA
  2. 1.8 11km S of Rio Dell, CA
  3. 2.2 8km N of Petrolia, CA
  4. 2.7 2km NNE of Petrolia, CA
  5. 2.5 11km WSW of Petrolia, CA
  6. 2.1 17km W of Humboldt Hill, CA
  7. 1.7 13km SSW of Ferndale, CA
  8. 2.4 8km W of Petrolia, CA
  9. 2.4 11km W of Petrolia, CA
  10. 1.8 11km SSW of Ferndale, CA
  11. 2.7 24km W of Petrolia, CA
  12. 2.3 4km ENE of Petrolia, CA
  13. 1.5 17km E of Rio Dell, CA
  14. 2.5 30km W of Petrolia, CA
  15. 2.1 18km WNW 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

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