QuakeIndex

Earthquake · reviewed by a seismologist

M 6.4mw

Earthquake near Ferndale, CA

No earthquake was likely felt in Ferndale in the 24 hours to 9:22 pm PST (05:22 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 6.4 earthquake was recorded 15 km (9 mi) west-southwest of Ferndale, CA, at 2:34 am PST on 20 December 2022 (10:34 UTC), 18 km deep. 5,910 people have reported feeling it to USGS.

USGS: 15km WSW of Ferndale, CA

2:34 am PST, Dec 20, 2022 · · 18 km deep · released about 60 kilotons of TNT

Every earthquake near Ferndale Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Humboldt County 47 kmTrinity County 111 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
2:34 am PST on 20 December 2022 ()
Where
15 km (9 mi) west-southwest of Ferndale, CA · earthquakes near Ferndale
Magnitude
M 6.4 (mw)
Depth
18 km below the surface
Felt
5,910 reports · strongest reported intensity VII
Measured shaking
intensity VIII (ShakeMap)
USGS impact alert
orange
Tsunami
USGS flagged this event for tsunami evaluation. Follow tsunami.gov for official messages.
Nearest
Humboldt County, 47 km ENE
Nearest mapped fault
Little Salmon fault, 24 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 311 days ago

This was a strong earthquake. Damage is likely near the epicentre and it is felt over a wide area.

At this magnitude and depth, people at rest would likely notice it out to about 430 km (267 mi) from the epicentre. In Ferndale, 15 km away, the estimate is intensity VI (strong). 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 15 km, intensity VI · Fortuna 24 km, intensity VI · Rio Dell 27 km, intensity VI · Humboldt Hill 30 km, intensity VI · Eureka 38 km, intensity V · Bayside 47 km, intensity V. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 60 kilotons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 7.4 would have released about 32 times as much.

  1. Ridgecrest, California 2019 M 7.1 11× the energy of this one
  2. Loma Prieta, California 1989 M 6.9 5.6× the energy of this one
  3. Northridge, California 1994 M 6.7 2.8× the energy of this one
  4. This earthquake M 6.4 about 60 kilotons of TNT
  5. Mineral, Virginia 2011 M 5.8 this one released 7.9× more
  6. Magna, Utah 2020 M 5.7 this one released 11× 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 (31 mi) since our catalogue begins in 2016. The previous largest was M 6.2 on 2021-12-20.

Before 2016, the USGS record lists 45 earthquakes of M5 or more within 50 km; the five largest:

  1. 7.2 The 1992 Petrolia, California Earthquake · 27 km SE of this epicentre
  2. 6.6 32 km SW of Ferndale, California · 19 km SW of this epicentre
  3. 6.5 The 1932 Eureka, California Earthquake · 25 km NNE of this epicentre
  4. 6.5 30 km WSW of Ferndale, California · 16 km SW of this epicentre
  5. 6.5 The 2010 Eureka, California Earthquake · 27 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 40.5250, -124.4230. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Humboldt County, CA 47 km (29 mi) ENE earthquakes near Humboldt County
Trinity County, CA 111 km (69 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.

  1. 2.1 12km WSW of Ferndale, CA
  2. 1.8 16km WSW of Ferndale, CA
  3. 2.1 13km WSW of Ferndale, CA
  4. 2.1 16km WSW of Ferndale, CA
  5. 2.4 4km SE of Fortuna, CA
  6. 2.5 21km WSW of Ferndale, CA
  7. 2.0 5km SSW of Ferndale, CA
  8. 3.0 5km E of Fortuna, CA
  9. 2.6 6km SW of Ferndale, CA
  10. 2.1 5km ESE of Ferndale, CA
  11. 2.2 5km SE of Ferndale, CA
  12. 2.5 7km SW of Ferndale, CA
  13. 2.2 21km SW of Ferndale, CA
  14. 1.7 2km SW of Fortuna, CA
  15. 2.4 5km N of Hydesville, 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.