QuakeIndex

Earthquake · automatic estimate, may change

M 2.3md

Earthquake near Brooktrails, CA

No earthquake was likely felt in Brooktrails in the 24 hours to 8:35 am PST (16:35 UTC). The last one was M 4.0, 38 km (23 mi) E, at 5:01 am PDT on 28 October 2026, estimated intensity III (weak) in town; 14 felt reports to USGS. Every earthquake near Brooktrails

This page: a magnitude 2.3 earthquake was recorded 10 km (6 mi) north-northeast of Brooktrails, CA, at 11:04 pm PST on 9 December 2025 (07:04 UTC), 8.1 km deep. The magnitude and location are an automatic first estimate and may change.

USGS: 10 km NNE of Brooktrails, CA

11:04 pm PST, Dec 9, 2025 · · 8.1 km deep · released about 77 lb of TNT

10 km30 km60 km120 km N Mendocino County 14 kmLake County 68 kmGlenn County 80 kmColusa County 101 kmTehama County 115 kmSonoma County 116 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
11:04 pm PST on 9 December 2025 ()
Where
10 km (6 mi) north-northeast of Brooktrails, CA · earthquakes near Brooktrails
Magnitude
M 2.3 (md)
Depth
8.1 km below the surface
Felt
no reports yet
Nearest
Mendocino County, 14 km SW
Nearest mapped fault
Maacama fault, 7 km from its surface trace — near is not the same as on
Status
Automatic — a machine’s first estimate, which may change

USGS · last changed by USGS · we first saw it 337 days ago

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

At this magnitude and depth, people at rest would likely notice it out to about 18 km (11 mi) from the epicentre. In Brooktrails, 10 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: Brooktrails 10 km, intensity II · Willits 13 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 77 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.3 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 200,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 140,000× the energy of this one
  3. Around the size people start to feel M 3.0 12× the energy of this one
  4. This earthquake M 2.3 about 77 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 4.3 on 2024-06-22 — about 1,300 times the energy of this one.

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

  1. 5.9 9 km S of Leggett, California · 45 km NW of this epicentre
  2. 5.2 6 km ESE of Talmage, California · 49 km SSE 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 39.5228, -123.3285. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Mendocino County, CA 14 km (9 mi) SW earthquakes near Mendocino County
Lake County, CA 68 km (42 mi) SE earthquakes near Lake County
Glenn County, CA 80 km (50 mi) E earthquakes near Glenn County
Colusa County, CA 101 km (63 mi) ESE earthquakes near Colusa County
Tehama County, CA 115 km (72 mi) NE earthquakes near Tehama County
Sonoma County, CA 116 km (72 mi) SSE earthquakes near Sonoma County

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

Aftershocks so far

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

  1. 2.7 15 km N of Brooktrails, CA
  2. 2.1 3 km SSE of Redwood Valley, CA
  3. 1.5 4 km NW of Redwood Valley, CA
  4. 2.2 3 km SSE of Redwood Valley, CA
  5. 1.6 12 km N of Redwood Valley, CA
  6. 1.7 15 km NE of Willits, CA
  7. 2.0 9 km SSE of Lake Pillsbury, CA
  8. 1.8 9 km SSE of Lake Pillsbury, CA
  9. 2.1 8 km E of Covelo, CA
  10. 2.1 15 km SE of Laytonville, CA
  11. 1.7 16 km ESE of Lake Pillsbury, CA
  12. 1.7 15 km N of Brooktrails, CA
  13. 1.7 10 km ESE of Willits, CA
  14. 1.6 11 km ESE of Willits, CA
  15. 1.6 16 km SSW of Laytonville, 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.