QuakeIndex

Earthquake · reviewed by a seismologist

M 1.9md

Earthquake near Arbuckle, CA

No earthquake was likely felt in Arbuckle in the 24 hours to 10:20 am PST (18:20 UTC). The last one was M 4.0, 94 km (58 mi) NW, at 5:01 am PDT on 28 October 2026, estimated intensity II (weak) in town; 14 felt reports to USGS. Every earthquake near Arbuckle

This page: a magnitude 1.9 earthquake was recorded 6 km (4 mi) southwest of Arbuckle, CA, at 8:40 am PST on 11 November 2021 (16:40 UTC), 27 km deep.

USGS: 6km SW of Arbuckle, CA

72 km (45 mi) NW of Sacramento, CA · 43 km (27 mi) WSW of Yuba City, CA

8:40 am PST, Nov 11, 2021 · · 27 km deep · released about 24 lb of TNT

10 km30 km60 km120 km N Colusa County 25 kmSutter County 35 kmYolo County 38 kmNapa County 56 kmLake County 57 kmYuba County 73 kmGlenn County 74 kmSolano County 80 kmSonoma County 87 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
8:40 am PST on 11 November 2021 ()
Where
6 km (4 mi) southwest of Arbuckle, CA · earthquakes near Arbuckle
Magnitude
M 1.9 (md)
Depth
27 km below the surface
Felt
no reports yet
Nearest
Colusa County, 25 km NNW
Nearest mapped fault
Great Valley thrust fault system, 8 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 1826 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 Arbuckle, 6 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: Dunnigan, Williams, Colusa.

How big was it?

This earthquake released about 24 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 5.8 640,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 450,000× the energy of this one
  3. Around the size people start to feel M 3.0 40× the energy of this one
  4. This earthquake M 1.9 about 24 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 38.9787, -122.1048. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Colusa County, CA 25 km (15 mi) NNW earthquakes near Colusa County
Sutter County, CA 35 km (22 mi) E earthquakes near Sutter County
Yolo County, CA 38 km (23 mi) SSE earthquakes near Yolo County
Napa County, CA 56 km (35 mi) SSW earthquakes near Napa County
Lake County, CA 57 km (36 mi) WNW earthquakes near Lake County
Yuba County, CA 73 km (45 mi) ENE earthquakes near Yuba County

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

Aftershocks so far

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

  1. 1.5 13km ESE of Hidden Valley Lake, CA
  2. 1.7 1km SE of Clearlake, CA
  3. 1.6 3km WNW of Lower Lake, CA
  4. 1.9 4km WNW of Lower Lake, CA
  5. 2.2 4km W of Lower Lake, CA
  6. 1.9 11km ENE of Hidden Valley Lake, CA
  7. 1.6 19km ENE of Clearlake Oaks, CA
  8. 1.7 14km E of Angwin, CA
  9. 1.5 15km E of Angwin, CA
  10. 1.6 13km ESE of Hidden Valley Lake, CA
  11. 2.0 12km ESE of Hidden Valley Lake, CA
  12. 1.9 12km ESE of Hidden Valley Lake, CA
  13. 2.0 12km ESE of Hidden Valley Lake, CA
  14. 1.7 17km E of Angwin, CA
  15. 2.2 15km ENE of Angwin, 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.