QuakeIndex

Earthquake · reviewed by a seismologist

M 1.6md

Earthquake near Willits, CA

No earthquake was likely felt in Willits in the 24 hours to 8:29 pm PST (04:29 UTC). The last one was M 1.5, 9 km (5 mi) ESE, at 10:30 pm PST on 2 November 2026, estimated intensity II (weak) in town. Every earthquake near Willits

This page: a magnitude 1.6 earthquake was recorded 4 km (3 mi) southeast of Willits, CA, at 3:04 pm PDT on 8 August 2019 (22:04 UTC), less than 1 km deep.

USGS: 4km SE of Willits, CA

3:04 pm PDT, Aug 8, 2019 · · -0.7 km deep · released about 7.3 lb of TNT

10 km30 km60 km120 km N Mendocino County 12 kmLake County 58 kmGlenn County 82 kmColusa County 96 kmSonoma County 101 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
3:04 pm PDT on 8 August 2019 ()
Where
4 km (3 mi) southeast of Willits, CA · earthquakes near Willits
Magnitude
M 1.6 (md)
Depth
-0.7 km below the surface
Felt
no reports yet
Nearest
Mendocino County, 12 km WNW
Nearest mapped fault
Maacama fault, under 1 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 2646 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 11 km (7 mi) from the epicentre. In Willits, 4 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: Willits 4 km, intensity II · Brooktrails 9 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 7.3 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 2,100,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,500,000× 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 7.3 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 5.1 on 2016-08-10 — about 180,000 times the energy of this one.

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

  1. 5.2 6 km ESE of Talmage, California · 35 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 39.3848, -123.3188. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Mendocino County, CA 12 km (7 mi) WNW earthquakes near Mendocino County
Lake County, CA 58 km (36 mi) ESE earthquakes near Lake County
Glenn County, CA 82 km (51 mi) ENE earthquakes near Glenn County
Colusa County, CA 96 km (60 mi) ESE earthquakes near Colusa County
Sonoma County, CA 101 km (63 mi) SSE earthquakes near Sonoma County
Tehama County, CA 124 km (77 mi) NE 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.

  1. 1.8 23km WNW of Alder Springs, CA
  2. 1.6 16km NE of Upper Lake, CA
  3. 1.7 8km NE of Upper Lake, CA
  4. 1.7 6km NW of North Lakeport, CA
  5. 1.9 6km SW of Upper Lake, CA
  6. 1.6 6km SW of Upper Lake, CA
  7. 2.3 16km SSW of Willits, CA
  8. 2.6 9km ESE of Redwood Valley, CA
  9. 2.3 14km SW of Laytonville, CA
  10. 2.1 6km N of Lake Pillsbury, CA
  11. 2.1 12km SE of Talmage, CA
  12. 2.7 12km SE of Talmage, CA
  13. 2.2 9km ESE of Redwood Valley, CA
  14. 1.9 4km NW of Redwood Valley, CA
  15. 1.9 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.