QuakeIndex

Earthquake · reviewed by a seismologist

M 3.2mw

Earthquake near Angwin, CA

No earthquake was likely felt in Angwin in the 24 hours to 3:22 am PST (11:22 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 3.2 earthquake was recorded 14 km (9 mi) east of Angwin, CA, at 1:00 am PST on 11 February 2017 (09:00 UTC), 4.8 km deep. 5 people have reported feeling it to USGS.

USGS: 14 km E of Angwin, California

87 km (54 mi) N of San Francisco, CA · 29 km (18 mi) N of Napa, CA

1:00 am PST, Feb 11, 2017 · · 4.8 km deep · released about 1.1 tons of TNT

10 km30 km60 km120 km N Napa County 7 kmYolo County 36 kmSolano County 44 kmSonoma County 56 kmColusa County 69 kmMarin County 69 kmLake County 73 kmSutter County 73 kmContra Costa County 77 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
1:00 am PST on 11 February 2017 ()
Where
14 km (9 mi) east of Angwin, CA · earthquakes near Angwin
Magnitude
M 3.2 (mw)
Depth
4.8 km below the surface
Felt
5 reports · strongest reported intensity II
Nearest
Napa County, 7 km SSW
Nearest mapped fault
Hunting Creek-Berryessa fault system, 3 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 1787 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

At this magnitude and depth, people at rest would likely notice it out to about 48 km (30 mi) from the epicentre. In Angwin, 14 km away, the estimate is intensity III (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 14 km, intensity III · Calistoga 26 km, intensity II · Kenwood 28 km, intensity II · Napa 29 km, intensity II · Agua Caliente 31 km, intensity II · Vacaville 34 km, intensity II · Monument Hills 38 km, intensity II · Santa Rosa 39 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 1.1 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.2 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 150,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 6,900× the energy of this one
  3. Magna, Utah 2020 M 5.7 4,900× the energy of this one
  4. This earthquake M 3.2 about 1.1 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 2.3× more

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 lists 2 earthquakes of M5 or more within 50 km:

  1. 6.0 The 2014 South Napa, California Earthquake · 38 km S of this epicentre
  2. 5.4 South of Elmira, California · 44 km SE 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 38.5592, -122.2873. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Napa County, CA 7 km (4 mi) SSW earthquakes near Napa County
Yolo County, CA 36 km (22 mi) ENE earthquakes near Yolo County
Solano County, CA 44 km (28 mi) SE earthquakes near Solano County
Sonoma County, CA 56 km (35 mi) W earthquakes near Sonoma County
Colusa County, CA 69 km (43 mi) N earthquakes near Colusa County
Marin County, CA 69 km (43 mi) SW earthquakes near Marin County

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

Aftershocks so far

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

  1. 1.9 7 km S of Calistoga, California
  2. 1.9 4 km SW of Cobb, California
  3. 1.5 2 km E of Saint Helena, California
  4. 2.7 4 km S of Cobb, California
  5. 2.6 5 km SW of Cobb, California
  6. 1.6 6 km SW of Cobb, California
  7. 1.5 9 km S of Cobb, California
  8. 1.7 6 km S of Cobb, California
  9. 1.6 7 km W of Middletown, California
  10. 1.6 7 km W of Middletown, California
  11. 1.8 3 km S of Cobb, California
  12. 1.6 7 km S of Cobb, California
  13. 1.6 2 km S of Cobb, California
  14. 1.6 3 km S of Cobb, California
  15. 1.8 3 km SSW of Cobb, California

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.