QuakeIndex

Earthquake · reviewed by a seismologist

M 3.3mw

2 km ENE of Angwin, California

· 6.1 km deep · released about 1.2 tons of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Napa County 12 kmSonoma County 45 kmYolo County 46 kmSolano County 55 kmLake County 65 kmMarin County 66 kmColusa County 68 kmSutter County 80 kmContra Costa County 84 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
Magnitude
M 3.3 (mw)
Depth
6.1 km below the surface
Felt
133 reports · strongest reported intensity III
Nearest
Napa County, 12 km SE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3271 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 133 people have reported feeling it to USGS.

How big was it?

This earthquake released about 1.2 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.3 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 140,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 6,200× the energy of this one
  3. Magna, Utah 2020 M 5.7 4,400× the energy of this one
  4. This earthquake M 3.3 about 1.2 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 2.5× 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.

Where

Epicentre 38.5840, -122.4187. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Napa County, CA 12 km (7 mi) NW of here earthquakes near Napa County
Sonoma County, CA 45 km (28 mi) E of here earthquakes near Sonoma County
Yolo County, CA 46 km (29 mi) WSW of here earthquakes near Yolo County
Solano County, CA 55 km (34 mi) NW of here earthquakes near Solano County
Lake County, CA 65 km (40 mi) SSE of here earthquakes near Lake County
Marin County, CA 66 km (41 mi) NNE of here earthquakes near Marin 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. 1.6 1km NNW of The Geysers, CA
  2. 3.5 5 km WSW of Cobb, California
  3. 2.5 12 km ENE of Cloverdale, California
  4. 1.6 2km NW of The Geysers, CA
  5. 1.8 1km SSW of Anderson Springs, CA
  6. 1.9 3 km W of Cobb, California
  7. 1.8 4km WNW of The Geysers, CA
  8. 1.5 3km W of Cobb, CA
  9. 1.7 1km NNW of The Geysers, CA
  10. 1.9 14 km WSW of Esparto, California
  11. 2.7 3 km W of Cobb, California
  12. 1.7 2km NNW of The Geysers, CA
  13. 2.2 4 km WNW of Cobb, California
  14. 1.5 5 km S of Cobb, California
  15. 1.5 7 km WSW 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.

For this area

The largest earthquake within 50 km in our catalogue was M 5.0 on 2016-12-14 — it released about 410 times the energy of this one.

From the QuakeIndex catalogue, built from the USGS FDSN event service.

On USGS

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.