QuakeIndex

Earthquake · reviewed by a seismologist

M 2.1md

7 km NNW of Bayview-Montalvin, CA

· 6.9 km deep · released about 40 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Marin County 34 kmContra Costa County 39 kmSolano County 43 kmNapa County 50 kmAlameda County 61 kmSan Francisco County 70 kmSonoma County 71 kmSan Mateo County 72 kmYolo County 79 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
6.9 km below the surface
Felt
no reports yet
Nearest
Marin County, 34 km W
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 789 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 38.0615, -122.3610. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Marin County, CA 34 km (21 mi) E of here earthquakes near Marin County
Contra Costa County, CA 39 km (24 mi) WNW of here earthquakes near Contra Costa County
Solano County, CA 43 km (27 mi) WSW of here earthquakes near Solano County
Napa County, CA 50 km (31 mi) S of here earthquakes near Napa County
Alameda County, CA 61 km (38 mi) NW of here earthquakes near Alameda County
San Francisco County, CA 70 km (43 mi) ENE 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

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

  1. 1.9 1 km WNW of Kensington, CA
  2. 2.5 1 km ESE of Pacheco, CA
  3. 2.0 7 km WSW of Glen Ellen, CA
  4. 1.9 2 km NW of Alamo, CA
  5. 1.6 4 km SW of Clayton, CA
  6. 1.9 2 km NW of Alamo, CA
  7. 1.6 2 km NW of Alamo, CA
  8. 1.7 3 km SW of Clayton, CA
  9. 1.6 1 km ENE of Danville, CA
  10. 1.6 7 km ESE of Santa Venetia, CA
  11. 1.5 6 km ENE of Vallejo, CA
  12. 1.6 5 km SSE of Napa, CA
  13. 1.6 9 km SE of Clayton, CA
  14. 2.4 1 km NNE of Oakland, CA
  15. 2.1 8 km N of Green Valley, 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 4.5 on 2019-10-15 — it released about 3,700 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.