QuakeIndex

Earthquake · reviewed by a seismologist

M 1.9md

Earthquake near Williams, CA

No earthquake was likely felt in Williams in the 24 hours to 7:56 am PST (15:56 UTC). The last one was M 4.0, 79 km (49 mi) WNW, at 5:01 am PDT on 28 October 2026, estimated intensity II (weak) in town; 14 felt reports to USGS. Every earthquake near Williams

This page: a magnitude 1.9 earthquake was recorded 7 km (4 mi) east-southeast of Williams, CA, at 10:06 pm PDT on 20 August 2026 (05:06 UTC), 20 km deep. 1 person has reported feeling it to USGS.

USGS: 7 km ESE of Williams, CA

82 km (51 mi) NW of Sacramento, CA · 37 km (23 mi) W of Yuba City, CA

10:06 pm PDT, Aug 20, 2026 · · 20 km deep · released about 21 lb of TNT

10 km30 km60 km120 km N Colusa County 15 kmSutter County 34 kmYolo County 53 kmLake County 58 kmGlenn County 59 kmYuba County 64 kmButte County 71 kmNapa County 73 kmSolano County 97 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
10:06 pm PDT on 20 August 2026 ()
Where
7 km (4 mi) east-southeast of Williams, CA · earthquakes near Williams
Magnitude
M 1.9 (md)
Depth
20 km below the surface
Felt
1 report
Nearest
Colusa County, 15 km WNW
Nearest mapped fault
Great Valley thrust fault system, 17 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 72 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth it was probably too small to be felt, even directly above it. In Williams, 7 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: Colusa, Arbuckle, Maxwell, Sutter, Dunnigan.

How big was it?

This earthquake released about 21 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.9 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 710,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 500,000× the energy of this one
  3. Around the size people start to feel M 3.0 45× the energy of this one
  4. This earthquake M 1.9 about 21 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

No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.

Before 2016, the USGS record since 1900 lists no earthquake of M5 or more within 50 km.

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 39.1375, -122.0728. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Colusa County, CA 15 km (9 mi) WNW earthquakes near Colusa County
Sutter County, CA 34 km (21 mi) ESE earthquakes near Sutter County
Yolo County, CA 53 km (33 mi) SSE earthquakes near Yolo County
Lake County, CA 58 km (36 mi) W earthquakes near Lake County
Glenn County, CA 59 km (37 mi) NNW earthquakes near Glenn County
Yuba County, CA 64 km (40 mi) ENE earthquakes near Yuba County

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

Aftershocks so far

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

  1. 2.8 8 km E of Lower Lake, CA
  2. 2.2 7 km ESE of Lower Lake, CA
  3. 1.5 8 km ESE of Lower Lake, CA
  4. 2.1 7 km ESE of Lower Lake, CA
  5. 2.5 8 km E of Lower Lake, CA
  6. 2.0 5 km E of Williams, CA
  7. 1.5 11 km ENE of Hidden Valley Lake, 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.