QuakeIndex

Earthquake · reviewed by a seismologist

M 2.7md

Earthquake near Humboldt Hill, CA

No earthquake was likely felt in Humboldt Hill in the 24 hours to 4:29 am PST (12:29 UTC). The last one was M 5.0, 123 km (76 mi) WSW, at 8:56 pm PST on 4 November 2026, estimated intensity II (weak) in town; 145 felt reports to USGS. Every earthquake near Humboldt Hill

This page: a magnitude 2.7 earthquake was recorded 3 km (2 mi) south-southwest of Humboldt Hill, CA, at 9:18 pm PST on 31 December 2022 (05:18 UTC), 18 km deep. 54 people have reported feeling it to USGS.

USGS: 3km SSW of Humboldt Hill, CA

9:18 pm PST, Dec 31, 2022 · · 18 km deep · released about 340 lb of TNT

Every earthquake near Humboldt Hill Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Humboldt County 24 kmTrinity County 92 kmDel Norte County 118 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
9:18 pm PST on 31 December 2022 ()
Where
3 km (2 mi) south-southwest of Humboldt Hill, CA · earthquakes near Humboldt Hill
Magnitude
M 2.7 (md)
Depth
18 km below the surface
Felt
54 reports · strongest reported intensity IV
Nearest
Humboldt County, 24 km E
Nearest mapped fault
Little Salmon fault, 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 1317 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 17 km (11 mi) from the epicentre. In Humboldt Hill, 3 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: Humboldt Hill 3 km, intensity II · Eureka 11 km, intensity II · Fortuna 12 km, intensity II · Ferndale 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 340 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.7 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 45,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 32,000× the energy of this one
  3. Around the size people start to feel M 3.0 2.8× the energy of this one
  4. This earthquake M 2.7 about 340 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 350,000 times the energy of this one.

Before 2016, the USGS record lists 33 earthquakes of M5 or more within 50 km; the five largest:

  1. 7.2 The 1980 Eureka, California Earthquake · 46 km N of this epicentre
  2. 7.2 The 1992 Petrolia, California Earthquake · 41 km S of this epicentre
  3. 6.6 32 km SW of Ferndale, California · 46 km SW of this epicentre
  4. 6.5 The 1932 Eureka, California Earthquake · 7 km WNW of this epicentre
  5. 6.5 30 km WSW of Ferndale, California · 43 km SW 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 40.7038, -124.2062. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Humboldt County, CA 24 km (15 mi) E earthquakes near Humboldt County
Trinity County, CA 92 km (57 mi) E earthquakes near Trinity County
Del Norte County, CA 118 km (73 mi) N earthquakes near Del Norte County

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

Aftershocks so far

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

  1. 3.1 4km ESE of Ferndale, CA
  2. 1.7 12km ESE of Rio Dell, CA
  3. 1.8 12km WSW of Ferndale, CA
  4. 2.1 19km WSW of Ferndale, CA
  5. 2.1 16km WSW of Ferndale, CA
  6. 2.4 5km SW of Ferndale, CA
  7. 2.4 12km W of Ferndale, CA
  8. 2.6 22km ENE of Hydesville, CA
  9. 2.9 10km NW of Petrolia, CA
  10. 2.6 29km W of Ferndale, CA
  11. 2.2 11km SSW of Ferndale, CA
  12. 1.8 7km SW of Ferndale, CA
  13. 2.9 19km WSW of Ferndale, CA
  14. 2.5 10km SE of Rio Dell, CA
  15. 1.8 17km ENE 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.