QuakeIndex

Earthquake · reviewed by a seismologist

M 2.4md

Earthquake near Willow Creek, CA

No earthquake was likely felt in Willow Creek in the 24 hours to 4:32 am PST (12:32 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 2.4 earthquake was recorded 20 km (13 mi) northeast of Willow Creek, CA, at 8:09 am PDT on 27 October 2020 (15:09 UTC), 38 km deep.

USGS: 20km NE of Willow Creek, CA

8:09 am PDT, Oct 27, 2020 · · 38 km deep · released about 120 lb of TNT

10 km30 km60 km120 km N Trinity County 55 kmHumboldt County 56 kmDel Norte County 87 kmSiskiyou County 97 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
8:09 am PDT on 27 October 2020 ()
Where
20 km (13 mi) northeast of Willow Creek, CA · earthquakes near Willow Creek
Magnitude
M 2.4 (md)
Depth
38 km below the surface
Felt
no reports yet
Nearest
Trinity County, 55 km SSE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2201 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, 20 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 120 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.4 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 120,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 86,000× the energy of this one
  3. Around the size people start to feel M 3.0 7.7× the energy of this one
  4. This earthquake M 2.4 about 120 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 4.4 on 2019-02-06 — about 930 times the energy of this one.

Before 2016, the USGS record lists 6 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.4 The 1954 Eureka-Arcata, California Earthquake · 44 km SW of this epicentre
  2. 5.6 15 km SW of Burnt Ranch, California · 42 km SSW of this epicentre
  3. 5.6 26 km NNW of Willow Creek, California · 29 km WNW of this epicentre
  4. 5.4 3 km NNW of Burnt Ranch, California · 26 km S of this epicentre
  5. 5.0 4 km NE of Fieldbrook, California · 46 km W 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 41.0692, -123.4602. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Trinity County, CA 55 km (34 mi) SSE earthquakes near Trinity County
Humboldt County, CA 56 km (35 mi) SW earthquakes near Humboldt County
Del Norte County, CA 87 km (54 mi) NNW earthquakes near Del Norte County
Siskiyou County, CA 97 km (60 mi) NE earthquakes near Siskiyou County
Shasta County, CA 124 km (77 mi) ESE earthquakes near Shasta County
Tehama County, CA 147 km (92 mi) SE earthquakes near Tehama County

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

Aftershocks so far

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

  1. 3.2 16km WSW of Weitchpec, CA
  2. 3.0 12km SSW of Somes Bar, CA
  3. 2.1 22km E of Willow Creek, CA
  4. 2.4 22km SE of Blue Lake, CA
  5. 2.0 10km NNW of Willow Creek, CA
  6. 2.1 30km WNW of Weaverville, CA
  7. 2.9 30km WNW of Weaverville, CA
  8. 2.5 5km SSE of Weitchpec, CA
  9. 2.7 6km S of Weitchpec, CA
  10. 2.7 21km WNW of Weitchpec, CA
  11. 2.2 22km SSE of Willow Creek, CA
  12. 2.3 22km SSE of Willow Creek, CA
  13. 2.2 22km SSE of Willow Creek, CA
  14. 3.5 16km NE of Willow Creek, CA
  15. 3.0 19km SE of Willow Creek, 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.