QuakeIndex

Earthquake · reviewed by a seismologist

M 2.5md

Earthquake near Hayfork, CA

No earthquake was likely felt in Hayfork in the 24 hours to 4:07 am PST (12:07 UTC). The last one was M 3.7, 42 km (26 mi) W, at 2:44 pm PDT on 7 September 2026, estimated intensity II (weak) in town; 15 felt reports to USGS. Every earthquake near Hayfork

This page: a magnitude 2.5 earthquake was recorded 27 km (17 mi) west-southwest of Hayfork, CA, at 9:52 am PDT on 15 August 2022 (16:52 UTC), 27 km deep.

USGS: 27km WSW of Hayfork, CA

9:52 am PDT, Aug 15, 2022 · · 27 km deep · released about 180 lb of TNT

10 km30 km60 km120 km N Trinity County 37 kmHumboldt County 50 kmTehama County 109 kmMendocino 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
9:52 am PDT on 15 August 2022 ()
Where
27 km (17 mi) west-southwest of Hayfork, CA · earthquakes near Hayfork
Magnitude
M 2.5 (md)
Depth
27 km below the surface
Felt
no reports yet
Nearest
Trinity County, 37 km NE
Nearest mapped fault
Bartlett Springs fault system, 23 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 1476 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 it was probably too small to be felt, even directly above it. In Hayfork, 27 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.

How big was it?

This earthquake released about 180 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 83,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 59,000× the energy of this one
  3. Around the size people start to feel M 3.0 5.2× the energy of this one
  4. This earthquake M 2.5 about 180 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 2,700 times the energy of this one.

Before 2016, the USGS record lists 2 earthquakes of M5 or more within 50 km:

  1. 5.6 15 km SW of Burnt Ranch, California · 34 km NNW of this epicentre
  2. 5.4 3 km NNW of Burnt Ranch, California · 45 km N 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 40.4320, -123.4543. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Trinity County, CA 37 km (23 mi) NE earthquakes near Trinity County
Humboldt County, CA 50 km (31 mi) NW earthquakes near Humboldt County
Tehama County, CA 109 km (68 mi) ESE earthquakes near Tehama County
Mendocino County, CA 111 km (69 mi) S earthquakes near Mendocino County
Shasta County, CA 125 km (77 mi) ENE earthquakes near Shasta County
Glenn County, CA 129 km (80 mi) SE earthquakes near Glenn County

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

Aftershocks so far

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

  1. 2.3 14km SE of Rio Dell, CA
  2. 2.4 12km SE of Rio Dell, CA
  3. 5.3 15km SE of Rio Dell, CA
  4. 2.2 17km E of Hydesville, CA
  5. 2.3 3km NE of Redway, CA
  6. 2.2 19km E of Rio Dell, CA
  7. 1.8 18km E of Hydesville, CA
  8. 2.1 11km E of Hydesville, CA
  9. 1.8 11km E of Hydesville, CA
  10. 2.2 10km ENE of Hydesville, CA
  11. 1.8 18km NE of Hydesville, CA
  12. 2.1 19km NE of Hydesville, CA
  13. 2.1 23km E of Hydesville, CA
  14. 1.7 13km E of Hydesville, CA
  15. 1.8 22km E 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.