Earthquake · reviewed by a seismologist
M 1.8md
Earthquake near Brooktrails, CA
No earthquake was likely felt in Brooktrails in the 24 hours to 6:02 am PST (14:02 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 1.8 earthquake was recorded 18 km (11 mi) west-northwest of Brooktrails, CA, at 3:24 pm PDT on 6 May 2018 (22:24 UTC), 6.3 km deep.
USGS: 18km WNW of Brooktrails, CA
- When
- 3:24 pm PDT on 6 May 2018 ()
- Where
- 18 km (11 mi) west-northwest of Brooktrails, CA · earthquakes near Brooktrails
- Magnitude
- M 1.8 (md)
- Depth
- 6.3 km below the surface
- Felt
- no reports yet
- Nearest
- Mendocino County, 14 km ESE
- Nearest mapped fault
- Maacama fault, 14 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 3109 days ago
Earthquake alerts for Brooktrails, CA
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Alerts are on for .
Not a warning. An alert comes after USGS publishes a quake, usually minutes after the shaking. For early warning use ShakeAlert, through your phone's Wireless Emergency Alerts or the MyShake app.
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 11 km (7 mi) from the epicentre. In Brooktrails, 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.
Earthquakes near other towns within 30 km: Fort Bragg, Willits, Laytonville.
How big was it?
This earthquake released about 13 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 1,100,000× the energy of this one
- Magna, Utah 2020 M 5.7 810,000× the energy of this one
- Around the size people start to feel M 3.0 72× the energy of this one
- This earthquake M 1.8 about 13 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 5,600 times the energy of this one.
Before 2016, the USGS record lists one earthquake of M5 or more within 50 km:
- 5.9 9 km S of Leggett, California · 35 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 39.4928, -123.5857. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Mendocino County, CA | 14 km (9 mi) | ESE | earthquakes near Mendocino County |
| Lake County, CA | 84 km (52 mi) | ESE | earthquakes near Lake County |
| Glenn County, CA | 102 km (64 mi) | E | earthquakes near Glenn County |
| Colusa County, CA | 121 km (75 mi) | ESE | earthquakes near Colusa County |
| Sonoma County, CA | 122 km (76 mi) | SSE | earthquakes near Sonoma County |
| Tehama County, CA | 135 km (84 mi) | ENE | earthquakes near Tehama County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
54 earthquakes have been recorded within 50 km since this one.
- 2.3 7km E of Willits, CA
- 1.6 7km ENE of Willits, CA
- 1.8 13km SSE of Laytonville, CA
- 1.6 10km SSE of Laytonville, CA
- 1.6 14km SW of Laytonville, CA
- 1.9 7km NE of Brooktrails, CA
- 2.2 6km ESE of Willits, CA
- 1.9 4km NNE of Laytonville, CA
- 3.8 6km ENE of Willits, CA
- 1.8 12km SE of Laytonville, CA
- 1.8 21km N of Laytonville, CA
- 1.9 22km N of Laytonville, CA
- 2.1 6km SE of Redwood Valley, CA
- 1.8 8km NNW of Redwood Valley, CA
- 1.8 14km WNW of Lake Pillsbury, 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
- The official USGS event page — the source of record for every value above
- Did you feel it? Report it to USGS — reports go to USGS, not to us
- ShakeMap for this event, when USGS has produced one
QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.