QuakeIndex

Earthquake · reviewed by a seismologist

M 2.5md

12km ESE of Angwin, CA

· 8.2 km deep · released about 140 lb of TNT

10 km30 km60 km120 km N Napa County 3 kmYolo County 39 kmSolano County 44 kmSonoma County 53 kmMarin County 65 kmColusa County 72 kmLake County 74 kmContra Costa County 76 kmSutter 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 2.5 (md)
Depth
8.2 km below the surface
Felt
8 reports · strongest reported intensity III
Nearest
Napa County, 3 km SSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2353 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage. 8 people have reported feeling it to USGS.

How big was it?

This earthquake released about 140 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.5 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 110,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 75,000× the energy of this one
  3. Around the size people start to feel M 3.0 6.7× the energy of this one
  4. This earthquake M 2.5 about 140 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.

Where

Epicentre 38.5347, -122.3173. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Napa County, CA 3 km (2 mi) NNE of here earthquakes near Napa County
Yolo County, CA 39 km (25 mi) WSW of here earthquakes near Yolo County
Solano County, CA 44 km (28 mi) NW of here earthquakes near Solano County
Sonoma County, CA 53 km (33 mi) E of here earthquakes near Sonoma County
Marin County, CA 65 km (41 mi) NE of here earthquakes near Marin County
Colusa County, CA 72 km (45 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

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

  1. 1.8 6km NE of Penngrove, CA
  2. 1.5 6km ENE of Vallejo, CA
  3. 2.6 2km NNW of The Geysers, CA
  4. 1.8 14km E of Angwin, CA
  5. 1.6 15km E of Angwin, CA
  6. 2.1 2km N of The Geysers, CA
  7. 2.1 3km W of Anderson Springs, CA
  8. 1.7 8km ENE of Lower Lake, CA
  9. 2.8 2km SE of The Geysers, CA
  10. 2.0 1km E of The Geysers, CA
  11. 2.1 10km ESE of Hidden Valley Lake, CA
  12. 2.7 2km NE of The Geysers, CA
  13. 1.9 2km SW of Cobb, CA
  14. 2.1 6km WSW of Glen Ellen, CA
  15. 1.5 5km E of Vallejo, 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 450 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.