QuakeIndex

Earthquake · reviewed by a seismologist

M 1.5md

Earthquake near Angwin, CA

No earthquake was likely felt in Angwin in the 24 hours to 7:32 am PST (15:32 UTC). The last one was M 1.6, in Angwin, at 11:57 pm PDT on 10 October 2026, estimated intensity II (weak) in town. Every earthquake near Angwin

This page: a magnitude 1.5 earthquake was recorded 3 km (2 mi) north-northwest of Angwin, CA, at 6:07 am PST on 10 February 2023 (14:07 UTC), less than 1 km deep.

USGS: 3km NNW of Angwin, CA

91 km (57 mi) N of San Francisco, CA · 27 km (17 mi) NE of Santa Rosa, CA

6:07 am PST, Feb 10, 2023 · · -0.0 km deep · released about 5.9 lb of TNT

10 km30 km60 km120 km N Napa County 16 kmSonoma County 41 kmYolo County 50 kmSolano County 59 kmLake County 61 kmMarin County 66 kmColusa County 67 kmSutter County 82 kmContra Costa County 88 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
6:07 am PST on 10 February 2023 ()
Where
3 km (2 mi) north-northwest of Angwin, CA · earthquakes near Angwin
Magnitude
M 1.5 (md)
Depth
-0.0 km below the surface
Felt
no reports yet
Nearest
Napa County, 16 km SE
Nearest mapped fault
Hunting Creek-Berryessa fault system, 11 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 1370 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 10 km (6 mi) from the epicentre. In Angwin, 3 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: Angwin 3 km, intensity II · Calistoga 10 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 5.9 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.5 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 2,500,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,800,000× the energy of this one
  3. Around the size people start to feel M 3.0 160× the energy of this one
  4. This earthquake M 1.5 about 5.9 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 170,000 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 · 45 km SSE of this epicentre
  2. 5.3 3 km E of Bloomfield, California · 43 km SW of this epicentre
  3. 5.3 Northern California · 44 km SW 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 38.6002, -122.4692. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Napa County, CA 16 km (10 mi) SE earthquakes near Napa County
Sonoma County, CA 41 km (25 mi) WSW earthquakes near Sonoma County
Yolo County, CA 50 km (31 mi) E earthquakes near Yolo County
Solano County, CA 59 km (37 mi) SE earthquakes near Solano County
Lake County, CA 61 km (38 mi) NNW earthquakes near Lake County
Marin County, CA 66 km (41 mi) SSW earthquakes near Marin County

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

Aftershocks so far

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

  1. 3.3 8km NW of The Geysers, CA
  2. 2.0 7km WNW of The Geysers, CA
  3. 2.1 8km NW of The Geysers, CA
  4. 1.7 8km NW of The Geysers, CA
  5. 2.0 8km NW of The Geysers, CA
  6. 2.9 5km WNW of The Geysers, CA
  7. 1.5 5km WNW of The Geysers, CA
  8. 2.2 3km SE of The Geysers, CA
  9. 1.6 7km W of Cobb, CA
  10. 1.8 7km WNW of Cobb, CA
  11. 1.5 2km NNE of The Geysers, CA
  12. 1.6 7km WNW of Cobb, CA
  13. 1.6 8km WNW of The Geysers, CA
  14. 1.8 8km W of Cobb, CA
  15. 2.2 1km NE 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.