QuakeIndex

Earthquake · reviewed by a seismologist

M 2.1md

6km NE of Penngrove, CA

· 6.4 km deep · released about 40 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Napa County 32 kmSonoma County 33 kmMarin County 34 kmSolano County 61 kmYolo County 73 kmContra Costa County 76 kmSan Francisco County 77 kmLake County 86 kmColusa County 99 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 2.1 (md)
Depth
6.4 km below the surface
Felt
no reports yet
Nearest
Napa County, 32 km NE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2943 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

How big was it?

This earthquake released about 40 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.1 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 380,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 270,000× the energy of this one
  3. Around the size people start to feel M 3.0 24× the energy of this one
  4. This earthquake M 2.1 about 40 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 38.3428, -122.6275. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Napa County, CA 32 km (20 mi) SW of here earthquakes near Napa County
Sonoma County, CA 33 km (20 mi) SE of here earthquakes near Sonoma County
Marin County, CA 34 km (21 mi) NNE of here earthquakes near Marin County
Solano County, CA 61 km (38 mi) W of here earthquakes near Solano County
Yolo County, CA 73 km (46 mi) WSW of here earthquakes near Yolo County
Contra Costa County, CA 76 km (47 mi) NW of here earthquakes near Contra Costa County

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

Aftershocks so far

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

  1. 2.7 2km NW of Crockett, CA
  2. 3.5 2km NW of Crockett, CA
  3. 1.7 10km SW of The Geysers, CA
  4. 1.6 3km SW of Anderson Springs, CA
  5. 1.5 8km SW of Calistoga, CA
  6. 2.4 2km E of The Geysers, CA
  7. 1.7 2km W of Anderson Springs, CA
  8. 1.7 8km ENE of Larkfield-Wikiup, CA
  9. 1.7 2km SSW of Anderson Springs, CA
  10. 1.6 4km NE of Vallejo, CA
  11. 1.5 4km NE of Saint Helena, CA
  12. 1.5 2km WSW of Anderson Springs, CA
  13. 1.8 9km SSW of Calistoga, CA
  14. 1.6 4km SSW of Anderson Springs, CA
  15. 2.1 12km E of Angwin, 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.