QuakeIndex

Earthquake · reviewed by a seismologist

M 1.7md

Earthquake near Larkfield-Wikiup, CA

No earthquake was likely felt in Larkfield-Wikiup in the 24 hours to 11:30 am PST (19:30 UTC). The last one was M 1.9, 8 km (5 mi) ESE, at 2:01 pm PDT on 23 October 2026, estimated intensity II (weak) in town. Every earthquake near Larkfield-Wikiup

This page: a magnitude 1.7 earthquake was recorded 4 km (2 mi) north-northwest of Larkfield-Wikiup, CA, at 10:19 pm PST on 10 December 2021 (06:19 UTC), 9.0 km deep.

USGS: 4km NNW of Larkfield-Wikiup, CA

12 km (8 mi) NNW of Santa Rosa, CA

10:19 pm PST, Dec 10, 2021 · · 9.0 km deep · released about 9.3 lb of TNT

10 km30 km60 km120 km N Sonoma County 15 kmNapa County 38 kmMarin County 55 kmLake County 62 kmYolo County 76 kmSolano County 78 kmColusa County 83 kmSan Francisco County 94 kmContra Costa County 99 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
10:19 pm PST on 10 December 2021 ()
Where
4 km (2 mi) north-northwest of Larkfield-Wikiup, CA · earthquakes near Larkfield-Wikiup
Magnitude
M 1.7 (md)
Depth
9.0 km below the surface
Felt
no reports yet
Nearest
Sonoma County, 15 km W
Nearest mapped fault
Rodgers Creek 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 1793 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 8 km (5 mi) from the epicentre. In Larkfield-Wikiup, 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: Windsor 5 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 9.3 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.7 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,600,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,100,000× the energy of this one
  3. Around the size people start to feel M 3.0 100× the energy of this one
  4. This earthquake M 1.7 about 9.3 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 5.0 on 2016-12-14 — about 110,000 times the energy of this one.

Before 2016, the USGS record lists 2 earthquakes of M5 or more within 50 km:

  1. 5.3 3 km E of Bloomfield, California · 26 km S of this epicentre
  2. 5.3 Northern California · 26 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 38.5483, -122.7602. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Sonoma County, CA 15 km (9 mi) W earthquakes near Sonoma County
Napa County, CA 38 km (24 mi) E earthquakes near Napa County
Marin County, CA 55 km (34 mi) S earthquakes near Marin County
Lake County, CA 62 km (39 mi) N earthquakes near Lake County
Yolo County, CA 76 km (47 mi) ENE earthquakes near Yolo County
Solano County, CA 78 km (48 mi) ESE earthquakes near Solano County

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

Aftershocks so far

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

  1. 1.7 7km WNW of Cobb, CA
  2. 2.6 7km W of Cobb, CA
  3. 2.0 5km W of Yountville, CA
  4. 2.3 3km SW of Anderson Springs, CA
  5. 1.6 5km NW of The Geysers, CA
  6. 1.7 8km NW of The Geysers, CA
  7. 2.1 4km WNW of The Geysers, CA
  8. 2.3 7km W of Cobb, CA
  9. 1.7 2km WNW of Anderson Springs, CA
  10. 1.7 8km NW of The Geysers, CA
  11. 2.1 6km ENE of Kenwood, CA
  12. 2.1 3km SE of The Geysers, CA
  13. 1.8 8km WNW of Cobb, CA
  14. 1.6 1km ESE of The Geysers, CA
  15. 2.3 9km WNW of The Geysers, 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.