QuakeIndex

Earthquake · reviewed by a seismologist

M 2.5md

Earthquake near Hydesville, CA

No earthquake was likely felt in Hydesville in the 24 hours to 4:01 am PST (12:01 UTC). The last one was M 5.0, 127 km (79 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 Hydesville

This page: a magnitude 2.5 earthquake was recorded 6 km (4 mi) north-northeast of Hydesville, CA, at 8:38 pm PST on 20 December 2022 (04:38 UTC), 16 km deep. 2 people have reported feeling it to USGS.

USGS: 6km NNE of Hydesville, CA

8:38 pm PST, Dec 20, 2022 · · 16 km deep · released about 190 lb of TNT

Every earthquake near Hydesville Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Humboldt County 18 kmTrinity County 82 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
8:38 pm PST on 20 December 2022 ()
Where
6 km (4 mi) north-northeast of Hydesville, CA · earthquakes near Hydesville
Magnitude
M 2.5 (md)
Depth
16 km below the surface
Felt
2 reports · strongest reported intensity I
Nearest
Humboldt County, 18 km NE
Nearest mapped fault
Little Salmon fault, 3 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 1353 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 16 km (10 mi) from the epicentre. In Hydesville, 6 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: Fortuna 6 km, intensity II · Rio Dell 12 km, intensity II · Ferndale 16 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 190 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.5 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 80,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 57,000× the energy of this one
  3. Around the size people start to feel M 3.0 5.1× the energy of this one
  4. This earthquake M 2.5 about 190 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 640,000 times the energy of this one.

Before 2016, the USGS record lists 34 earthquakes of M5 or more within 50 km; the five largest:

  1. 7.2 The 1992 Petrolia, California Earthquake · 32 km SSW of this epicentre
  2. 6.6 32 km SW of Ferndale, California · 47 km WSW of this epicentre
  3. 6.5 The 1932 Eureka, California Earthquake · 22 km NW of this epicentre
  4. 6.5 30 km WSW of Ferndale, California · 45 km WSW of this epicentre
  5. 6.4 The 1954 Eureka-Arcata, California Earthquake · 31 km NNE 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 40.6012, -124.0805. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Humboldt County, CA 18 km (11 mi) NE earthquakes near Humboldt County
Trinity County, CA 82 km (51 mi) E earthquakes near Trinity County

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

Aftershocks so far

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

  1. 2.1 4km SW of Ferndale, CA
  2. 2.2 9km WSW of Ferndale, CA
  3. 1.8 14km WSW of Ferndale, CA
  4. 1.9 6km SW of Ferndale, CA
  5. 2.1 19km NE of Hydesville, CA
  6. 1.7 6km SSW of Ferndale, CA
  7. 1.7 9km SW of Ferndale, CA
  8. 1.8 12km WSW of Ferndale, CA
  9. 2.2 12km WSW of Ferndale, CA
  10. 2.0 9km SW of Ferndale, CA
  11. 2.2 12km WSW of Ferndale, CA
  12. 2.2 13km WSW of Ferndale, CA
  13. 1.8 12km WSW of Ferndale, CA
  14. 3.8 6km NW of Petrolia, CA
  15. 2.1 11km WSW 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.