QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8md

4km E of Penngrove, CA

· 7.7 km deep · released about 15 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Marin County 30 kmNapa County 34 kmSonoma County 36 kmSolano County 59 kmContra Costa County 73 kmSan Francisco County 74 kmYolo County 75 kmLake County 90 kmAlameda County 96 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
7.7 km below the surface
Felt
no reports yet
Nearest
Marin County, 30 km SSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2753 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 15 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 1,000,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 710,000× the energy of this one
  3. Around the size people start to feel M 3.0 63× the energy of this one
  4. This earthquake M 1.8 about 15 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 38.3062, -122.6195. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Marin County, CA 30 km (19 mi) NNE of here earthquakes near Marin County
Napa County, CA 34 km (21 mi) SW of here earthquakes near Napa County
Sonoma County, CA 36 km (22 mi) SE of here earthquakes near Sonoma County
Solano County, CA 59 km (37 mi) W of here earthquakes near Solano County
Contra Costa County, CA 73 km (45 mi) NW of here earthquakes near Contra Costa County
San Francisco County, CA 74 km (46 mi) NNE of here earthquakes near San Francisco County

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

Aftershocks so far

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

  1. 1.7 4km ESE of American Canyon, CA
  2. 1.5 2km W of Crockett, CA
  3. 2.0 5km WSW of Yountville, CA
  4. 1.9 4km NE of Vallejo, CA
  5. 1.5 3km ESE of Rodeo, CA
  6. 1.6 5km SSW of Glen Ellen, CA
  7. 2.5 10km ESE of Black Point-Green Point, CA
  8. 1.9 10km ESE of Black Point-Green Point, CA
  9. 1.9 7km N of Kenwood, CA
  10. 2.6 10km NNE of Napa, CA
  11. 2.9 4km N of Rodeo, CA
  12. 1.6 10km ESE of Black Point-Green Point, CA
  13. 2.5 9km ESE of Black Point-Green Point, CA
  14. 2.8 9km ESE of Black Point-Green Point, CA
  15. 2.2 6km SE of Calistoga, 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.