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 5:58 pm PST (01:58 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 42 km (26 mi) east-northeast of Willits, CA, at 8:38 pm PDT on 31 August 2016 (03:38 UTC), 1.9 km deep.

USGS: 29 km NE of Potter Valley, California

8:38 pm PDT, Aug 31, 2016 · · 1.9 km deep · released about 6.8 lb of TNT

10 km30 km60 km120 km N Glenn County 43 kmMendocino County 49 kmLake County 49 kmColusa County 69 kmTehama County 87 kmButte County 111 kmSonoma County 112 kmSutter 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
8:38 pm PDT on 31 August 2016 ()
Where
42 km (26 mi) east-northeast of Willits, CA · earthquakes near Willits
Magnitude
M 1.6 (md)
Depth
1.9 km below the surface
Felt
no reports yet
Nearest
Glenn County, 43 km E
Nearest mapped fault
Bartlett Springs fault system, 9 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 3561 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, 42 km away, the estimate is intensity I (not felt). 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.

How big was it?

This earthquake released about 6.8 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 2,200,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,600,000× the energy of this one
  3. Around the size people start to feel M 3.0 140× the energy of this one
  4. This earthquake M 1.6 about 6.8 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 190,000 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 · 49 km SSW 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 39.5297, -122.8918. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Glenn County, CA 43 km (27 mi) E earthquakes near Glenn County
Mendocino County, CA 49 km (30 mi) WSW earthquakes near Mendocino County
Lake County, CA 49 km (30 mi) SSE earthquakes near Lake County
Colusa County, CA 69 km (43 mi) SE earthquakes near Colusa County
Tehama County, CA 87 km (54 mi) NE earthquakes near Tehama County
Butte County, CA 111 km (69 mi) E earthquakes near Butte 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. 1.7 5 km E of Covelo, California
  2. 1.5 20 km NNE of Upper Lake, California
  3. 1.8 17 km NE of Willits, California
  4. 1.7 7 km NNE of Brooktrails, California
  5. 1.5 18 km NE of Upper Lake, California
  6. 1.6 19 km NNE of Upper Lake, California
  7. 1.5 20 km NNE of Upper Lake, California
  8. 1.6 21 km E of Potter Valley, California
  9. 2.0 8 km SSE of Laytonville, California
  10. 1.7 18 km NE of Upper Lake, California
  11. 1.6 18 km NE of Upper Lake, California
  12. 1.8 18 km NNE of Upper Lake, California
  13. 1.8 17 km NNE of Upper Lake, California
  14. 2.2 20 km E of Potter Valley, California
  15. 2.1 20 km NNE of Upper Lake, California

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.