QuakeIndex

Earthquake · reviewed by a seismologist

M 1.6md

Earthquake near Brooktrails, CA

No earthquake was likely felt in Brooktrails in the 24 hours to 2:30 am PST (10:30 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 1.6 earthquake was recorded 15 km (9 mi) west-northwest of Brooktrails, CA, at 12:45 pm PST on 13 February 2018 (20:45 UTC), 5.8 km deep.

USGS: 15km WNW of Brooktrails, CA

12:45 pm PST, Feb 13, 2018 · · 5.8 km deep · released about 7.6 lb of TNT

10 km30 km60 km120 km N Mendocino County 11 kmLake County 81 kmGlenn County 99 kmColusa County 118 kmSonoma County 120 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
12:45 pm PST on 13 February 2018 ()
Where
15 km (9 mi) west-northwest of Brooktrails, CA · earthquakes near Brooktrails
Magnitude
M 1.6 (md)
Depth
5.8 km below the surface
Felt
no reports yet
Nearest
Mendocino County, 11 km SE
Nearest mapped fault
Maacama fault, 11 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 3192 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 10 km (6 mi) from the epicentre. In Brooktrails, 15 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.

Earthquakes near other towns within 30 km: Willits, Laytonville, Fort Bragg.

How big was it?

This earthquake released about 7.6 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.6 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 2,000,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,400,000× the energy of this one
  3. Around the size people start to feel M 3.0 130× the energy of this one
  4. This earthquake M 1.6 about 7.6 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 9,800 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 · 36 km NNW 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 39.4900, -123.5453. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Mendocino County, CA 11 km (7 mi) SE earthquakes near Mendocino County
Lake County, CA 81 km (50 mi) ESE earthquakes near Lake County
Glenn County, CA 99 km (61 mi) E earthquakes near Glenn County
Colusa County, CA 118 km (73 mi) ESE earthquakes near Colusa County
Sonoma County, CA 120 km (74 mi) SSE earthquakes near Sonoma County
Tehama County, CA 133 km (82 mi) ENE earthquakes near Tehama County

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

Aftershocks so far

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

  1. 1.8 7km W of Redwood Valley, CA
  2. 2.2 5km N of Fort Bragg, CA
  3. 1.8 3km NW of Redwood Valley, CA
  4. 1.6 7km SSW of Laytonville, CA
  5. 2.1 13km NNE of Rockport, CA
  6. 2.2 9km NNW of Redwood Valley, CA
  7. 1.7 3km WNW of Redwood Valley, CA
  8. 1.6 5km NW of Laytonville, CA
  9. 1.9 13km N of Brooktrails, CA
  10. 1.8 7km ENE of Covelo, CA
  11. 1.8 4km NNW of Redwood Valley, CA
  12. 1.6 9km NNW of Redwood Valley, CA
  13. 2.4 4km NNW of Laytonville, CA
  14. 1.6 7km SW of Laytonville, CA
  15. 2.2 4km NNW 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.