QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8md

9km ENE of Napa, CA

· 8.0 km deep · released about 17 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Napa County 22 kmSolano County 23 kmYolo County 46 kmContra Costa County 51 kmMarin County 58 kmSonoma County 67 kmSacramento County 75 kmAlameda County 80 kmSutter County 89 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 1.8 (md)
Depth
8.0 km below the surface
Felt
no reports yet
Nearest
Napa County, 22 km NNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2852 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 17 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 900,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 640,000× the energy of this one
  3. Around the size people start to feel M 3.0 57× the energy of this one
  4. This earthquake M 1.8 about 17 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 38.3360, -122.1910. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Napa County, CA 22 km (14 mi) SSE of here earthquakes near Napa County
Solano County, CA 23 km (14 mi) WNW of here earthquakes near Solano County
Yolo County, CA 46 km (28 mi) SSW of here earthquakes near Yolo County
Contra Costa County, CA 51 km (32 mi) NNW of here earthquakes near Contra Costa County
Marin County, CA 58 km (36 mi) ENE of here earthquakes near Marin County
Sonoma County, CA 67 km (42 mi) ESE of here earthquakes near Sonoma County

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

Aftershocks so far

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

  1. 1.8 8km W of Yountville, CA
  2. 3.7 6km SSW of Yountville, CA
  3. 2.1 1km N of Pacheco, CA
  4. 2.0 1km N of Pacheco, CA
  5. 1.8 13km E of Yountville, CA
  6. 1.5 1km N of Vine Hill, CA
  7. 2.0 2km W of Green Valley, CA
  8. 2.1 1km N of Vine Hill, CA
  9. 2.0 8km ENE of Angwin, CA
  10. 1.5 3km S of Crockett, CA
  11. 1.9 5km ENE of Angwin, CA
  12. 1.8 3km S of Angwin, CA
  13. 1.7 1km WSW of Angwin, CA
  14. 2.3 5km ENE of Kenwood, CA
  15. 1.7 4km W of Yountville, 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.