QuakeIndex

Earthquake · reviewed by a seismologist

M 2.2md

Earthquake near Hydesville, CA

No earthquake was likely felt in Hydesville in the 24 hours to 1:24 pm PST (21:24 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 2.2 earthquake was recorded 3 km (2 mi) east-northeast of Hydesville, CA, at 10:59 pm PDT on 20 August 2017 (05:59 UTC), 31 km deep.

USGS: 3 km ENE of Hydesville, California

10:59 pm PDT, Aug 20, 2017 · · 31 km deep · released about 69 lb of TNT

Every earthquake near Hydesville Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Humboldt County 20 kmTrinity County 80 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
10:59 pm PDT on 20 August 2017 ()
Where
3 km (2 mi) east-northeast of Hydesville, CA · earthquakes near Hydesville
Magnitude
M 2.2 (md)
Depth
31 km below the surface
Felt
no reports yet
Nearest
Humboldt County, 20 km NNE
Nearest mapped fault
Little Salmon fault, under 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 3367 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth it was probably too small to be felt, even directly above it. In Hydesville, 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.

Earthquakes near other towns within 30 km: Rio Dell, Fortuna, Ferndale, Pine Hills, Humboldt Hill, Cutten.

How big was it?

This earthquake released about 69 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.2 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 220,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 150,000× the energy of this one
  3. Around the size people start to feel M 3.0 14× the energy of this one
  4. This earthquake M 2.2 about 69 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 4.8 on 2016-07-21 — about 7,200 times the energy of this one.

Before 2016, the USGS record lists 32 earthquakes of M5 or more within 50 km; the five largest:

  1. 7.2 The 1992 Petrolia, California Earthquake · 28 km SSW of this epicentre
  2. 6.6 32 km SW of Ferndale, California · 46 km WSW of this epicentre
  3. 6.5 The 1932 Eureka, California Earthquake · 27 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 · 35 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 40.5548, -124.0598. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Humboldt County, CA 20 km (13 mi) NNE earthquakes near Humboldt County
Trinity County, CA 80 km (50 mi) E earthquakes near Trinity 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.

  1. 2.2 19km ESE of Pine Hills, CA
  2. 2.2 16km ESE of Pine Hills, CA
  3. 1.9 18km W of Petrolia, CA
  4. 3.0 12km WSW of Petrolia, CA
  5. 3.8 20km WSW of Petrolia, CA
  6. 2.2 3km NW of Redway, CA
  7. 2.3 3km NW of Redway, CA
  8. 2.3 9km WSW of Petrolia, CA
  9. 2.7 20km N of Redway, CA
  10. 3.9 28km WNW of Petrolia, CA
  11. 2.8 5km NE of Hydesville, CA
  12. 2.8 4km SSW of Humboldt Hill, CA
  13. 2.3 19km W of Petrolia, CA
  14. 2.1 5km SW of Humboldt Hill, CA
  15. 2.5 5km WSW of Humboldt Hill, 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.