QuakeIndex

Earthquake · reviewed by a seismologist

M 2.6md

Earthquake near Brooktrails, CA

No earthquake was likely felt in Brooktrails in the 24 hours to 11:37 pm PST (07:37 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 2.6 earthquake was recorded 9 km (6 mi) north-northeast of Brooktrails, CA, at 8:19 am PST on 21 January 2019 (16:19 UTC), 8.8 km deep.

USGS: 9km NNE of Brooktrails, CA

8:19 am PST, Jan 21, 2019 · · 8.8 km deep · released about 220 lb of TNT

10 km30 km60 km120 km N Mendocino County 12 kmLake County 70 kmGlenn County 83 kmColusa County 104 kmSonoma County 117 kmTehama County 117 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
8:19 am PST on 21 January 2019 ()
Where
9 km (6 mi) north-northeast of Brooktrails, CA · earthquakes near Brooktrails
Magnitude
M 2.6 (md)
Depth
8.8 km below the surface
Felt
no reports yet
Nearest
Mendocino County, 12 km SW
Nearest mapped fault
Maacama fault, 4 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 2791 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, people at rest would likely notice it out to about 21 km (13 mi) from the epicentre. In Brooktrails, 9 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 9 km, intensity II · Willits 13 km, intensity II · Laytonville 21 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 220 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.6 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 70,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 50,000× the energy of this one
  3. Around the size people start to feel M 3.0 4.4× the energy of this one
  4. This earthquake M 2.6 about 220 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 2017-12-14 — about 340 times the energy of this one.

Before 2016, the USGS record lists one earthquake of M5 or more within 50 km:

  1. 5.9 9 km S of Leggett, California · 43 km NW 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 39.5247, -123.3625. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Mendocino County, CA 12 km (8 mi) SW earthquakes near Mendocino County
Lake County, CA 70 km (44 mi) SE earthquakes near Lake County
Glenn County, CA 83 km (51 mi) E earthquakes near Glenn County
Colusa County, CA 104 km (65 mi) ESE earthquakes near Colusa County
Sonoma County, CA 117 km (73 mi) SSE earthquakes near Sonoma County
Tehama County, CA 117 km (73 mi) NE earthquakes near Tehama 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. 1.9 10km NNW of Redwood Valley, CA
  2. 1.8 9km ESE of Willits, CA
  3. 1.9 11km NNW of Redwood Valley, CA
  4. 2.0 11km NNW of Redwood Valley, CA
  5. 1.8 11km N of Redwood Valley, CA
  6. 1.8 10km NNW of Redwood Valley, CA
  7. 1.7 11km NNW of Redwood Valley, CA
  8. 2.0 11km NNW of Redwood Valley, CA
  9. 1.7 11km NNW of Redwood Valley, CA
  10. 1.8 13km SE of Lake Pillsbury, CA
  11. 1.9 10km NNW of Redwood Valley, CA
  12. 2.0 11km NNW of Redwood Valley, CA
  13. 1.6 21km SE of Covelo, CA
  14. 2.6 10km NNW of Redwood Valley, CA
  15. 1.8 10km NNW of Redwood Valley, 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.