QuakeIndex

Earthquake · reviewed by a seismologist

M 3.5mw

13km E of Angwin, CA

· 9.3 km deep · released about 2.3 tons of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Napa County 6 kmYolo County 38 kmSolano County 45 kmSonoma County 54 kmMarin County 68 kmColusa County 69 kmLake County 72 kmSutter County 75 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
Magnitude
M 3.5 (mw)
Depth
9.3 km below the surface
Felt
73 reports · strongest reported intensity IV
Measured shaking
intensity IV (ShakeMap)
Nearest
Napa County, 6 km SSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1906 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 73 people have reported feeling it to USGS.

How big was it?

This earthquake released about 2.3 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.5 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 72,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 3,200× the energy of this one
  3. Magna, Utah 2020 M 5.7 2,300× the energy of this one
  4. This earthquake M 3.5 about 2.3 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 4.9× 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 38.5575, -122.3060. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Napa County, CA 6 km (4 mi) NNE of here earthquakes near Napa County
Yolo County, CA 38 km (23 mi) WSW of here earthquakes near Yolo County
Solano County, CA 45 km (28 mi) NW of here earthquakes near Solano County
Sonoma County, CA 54 km (34 mi) E of here earthquakes near Sonoma County
Marin County, CA 68 km (42 mi) NE of here earthquakes near Marin County
Colusa County, CA 69 km (43 mi) S of here earthquakes near Colusa 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. 2.1 1km NW of The Geysers, CA
  2. 2.3 5km NNE of Windsor, CA
  3. 1.6 1km N of The Geysers, CA
  4. 2.2 4km WNW of The Geysers, CA
  5. 1.8 4km NW of The Geysers, CA
  6. 2.0 4km N of Larkfield-Wikiup, CA
  7. 1.9 7km SE of Lower Lake, CA
  8. 1.9 3km SE of The Geysers, CA
  9. 1.7 3km SE of The Geysers, CA
  10. 1.6 2km NNE of The Geysers, CA
  11. 1.8 3km WNW of The Geysers, CA
  12. 1.7 3km WNW of Cobb, CA
  13. 1.8 2km S of Angwin, CA
  14. 2.0 3km NNW of The Geysers, CA
  15. 1.7 10km ENE of Hidden Valley Lake, 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.

For this area

The largest earthquake within 50 km in our catalogue was M 4.2 on 2018-01-18 — it released about 14 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.