QuakeIndex

Earthquake · reviewed by a seismologist

M 2.0md

Earthquake near Willow Creek, CA

No earthquake was likely felt in Willow Creek in the 24 hours to 1:26 am PST (09:26 UTC). The last one was M 5.0, 175 km (109 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 Willow Creek

This page: a magnitude 2.0 earthquake was recorded 18 km (11 mi) east-southeast of Willow Creek, CA, at 9:05 pm PDT on 4 October 2021 (04:05 UTC), 23 km deep.

USGS: 18km ESE of Willow Creek, CA

9:05 pm PDT, Oct 4, 2021 · · 23 km deep · released about 27 lb of TNT

Every earthquake near Willow Creek Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Trinity County 37 kmHumboldt County 46 kmDel Norte County 107 kmSiskiyou County 109 kmShasta 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
9:05 pm PDT on 4 October 2021 ()
Where
18 km (11 mi) east-southeast of Willow Creek, CA · earthquakes near Willow Creek
Magnitude
M 2.0 (md)
Depth
23 km below the surface
Felt
no reports yet
Nearest
Trinity County, 37 km SE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1864 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 Willow Creek, 18 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 27 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.0 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 560,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 390,000× the energy of this one
  3. Around the size people start to feel M 3.0 35× the energy of this one
  4. This earthquake M 2.0 about 27 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 18,000 times the energy of this one.

Before 2016, the USGS record lists 7 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.4 The 1954 Eureka-Arcata, California Earthquake · 39 km W of this epicentre
  2. 5.8 Near Eureka, California · 48 km W of this epicentre
  3. 5.6 15 km SW of Burnt Ranch, California · 24 km SW of this epicentre
  4. 5.6 26 km NNW of Willow Creek, California · 42 km NW of this epicentre
  5. 5.4 3 km NNW of Burnt Ranch, California · 7 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 40.8802, -123.4343. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Trinity County, CA 37 km (23 mi) SE earthquakes near Trinity County
Humboldt County, CA 46 km (28 mi) WSW earthquakes near Humboldt County
Del Norte County, CA 107 km (66 mi) NNW earthquakes near Del Norte County
Siskiyou County, CA 109 km (68 mi) NE earthquakes near Siskiyou County
Shasta County, CA 118 km (73 mi) E earthquakes near Shasta County
Tehama County, CA 132 km (82 mi) SE earthquakes near Tehama County

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

Aftershocks so far

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

  1. 1.9 18km ENE of Hydesville, CA
  2. 2.4 17km ENE of Willow Creek, CA
  3. 1.6 31km WSW of Hayfork, CA
  4. 1.8 20km SSE of Willow Creek, CA
  5. 2.1 25km WNW of Weaverville, CA
  6. 2.0 7km W of Willow Creek, CA
  7. 2.4 14km E of Willow Creek, CA
  8. 2.3 28km ENE of Willow Creek, CA
  9. 1.7 31km W of Hayfork, CA
  10. 2.1 26km ESE of Willow Creek, CA
  11. 2.4 7km S of Somes Bar, CA
  12. 2.5 27km WSW of Hayfork, CA
  13. 2.3 14km SE of Bayside, CA
  14. 2.3 15km SE of Bayside, CA
  15. 3.6 14km SE of Bayside, 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.