QuakeIndex

Earthquake · reviewed by a seismologist

M 2.0md

Earthquake near Calistoga, CA

No earthquake was likely felt in Calistoga in the 24 hours to 7:46 am PST (15:46 UTC). The last one was M 3.0, 33 km (21 mi) NW, at 11:06 pm PDT on 14 October 2026, estimated intensity II (weak) in town; 1 felt report to USGS. Every earthquake near Calistoga

This page: a magnitude 2.0 earthquake was recorded 7 km (4 mi) west of Calistoga, CA, at 10:13 pm PDT on 23 August 2021 (05:13 UTC), 7.5 km deep. 8 people have reported feeling it to USGS.

USGS: 7km W of Calistoga, CA

14 km (9 mi) NNE of Santa Rosa, CA

10:13 pm PDT, Aug 23, 2021 · · 7.5 km deep · released about 29 lb of TNT

10 km30 km60 km120 km N Sonoma County 24 kmNapa County 30 kmMarin County 58 kmLake County 60 kmYolo County 67 kmSolano County 71 kmColusa County 77 kmContra Costa County 95 kmSutter County 98 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
10:13 pm PDT on 23 August 2021 ()
Where
7 km (4 mi) west of Calistoga, CA · earthquakes near Calistoga
Magnitude
M 2.0 (md)
Depth
7.5 km below the surface
Felt
8 reports · strongest reported intensity III
Nearest
Sonoma County, 24 km WSW
Nearest mapped fault
Maacama fault, 2 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 1903 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 14 km (9 mi) from the epicentre. In Calistoga, 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.

Likely felt in: Calistoga 7 km, intensity II · Windsor 14 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 29 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.0 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 520,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 370,000× the energy of this one
  3. Around the size people start to feel M 3.0 33× the energy of this one
  4. This earthquake M 2.0 about 29 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 34,000 times the energy of this one.

Before 2016, the USGS record lists 3 earthquakes of M5 or more within 50 km:

  1. 6.0 The 2014 South Napa, California Earthquake · 50 km SE of this epicentre
  2. 5.3 3 km E of Bloomfield, California · 31 km SSW of this epicentre
  3. 5.3 Northern California · 31 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 38.5685, -122.6575. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Sonoma County, CA 24 km (15 mi) WSW earthquakes near Sonoma County
Napa County, CA 30 km (18 mi) ESE earthquakes near Napa County
Marin County, CA 58 km (36 mi) S earthquakes near Marin County
Lake County, CA 60 km (38 mi) N earthquakes near Lake County
Yolo County, CA 67 km (41 mi) E earthquakes near Yolo County
Solano County, CA 71 km (44 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 6km NW of The Geysers, CA
  2. 1.7 6km NW of The Geysers, CA
  3. 1.7 3km SW of Anderson Springs, CA
  4. 2.6 3km NW of The Geysers, CA
  5. 1.6 10km NE of Healdsburg, CA
  6. 1.8 3km SE of Larkfield-Wikiup, CA
  7. 1.5 0km WNW of The Geysers, CA
  8. 2.0 9km WNW of The Geysers, CA
  9. 1.5 5km NW of The Geysers, CA
  10. 1.6 2km NW of Anderson Springs, CA
  11. 2.4 5km WNW of The Geysers, CA
  12. 1.8 3km ENE of The Geysers, CA
  13. 1.6 10km WNW of Calistoga, CA
  14. 2.5 5km NW of The Geysers, CA
  15. 1.7 6km WNW of Cobb, 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.