QuakeIndex

Earthquake · reviewed by a seismologist

M 2.1md

3km WNW of Crockett, CA

· 7.8 km deep · released about 49 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Contra Costa County 30 kmSolano County 35 kmMarin County 44 kmNapa County 50 kmAlameda County 54 kmSan Mateo County 73 kmYolo County 75 kmSan Francisco County 78 kmSonoma 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
7.8 km below the surface
Felt
4 reports · strongest reported intensity IV
Nearest
Contra Costa County, 30 km ESE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1810 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage. 4 people have reported feeling it to USGS.

How big was it?

This earthquake released about 49 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 5.8 310,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 220,000× the energy of this one
  3. Around the size people start to feel M 3.0 19× the energy of this one
  4. This earthquake M 2.1 about 49 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 38.0600, -122.2448. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Contra Costa County, CA 30 km (19 mi) WNW of here earthquakes near Contra Costa County
Solano County, CA 35 km (22 mi) SW of here earthquakes near Solano County
Marin County, CA 44 km (27 mi) E of here earthquakes near Marin County
Napa County, CA 50 km (31 mi) S of here earthquakes near Napa County
Alameda County, CA 54 km (34 mi) NNW of here earthquakes near Alameda County
San Mateo County, CA 73 km (45 mi) N of here earthquakes near San Mateo County

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

Aftershocks so far

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

  1. 2.6 2km SW of Colma, CA
  2. 1.5 2km S of Alamo, CA
  3. 2.3 4km NE of Fairview, CA
  4. 1.6 2km NE of San Ramon, CA
  5. 1.9 1km NW of Danville, CA
  6. 1.7 1km WNW of Danville, CA
  7. 1.6 6km E of Vallejo, CA
  8. 1.9 6km E of Vallejo, CA
  9. 1.6 3km SE of Concord, CA
  10. 1.6 7km WSW of Lagunitas-Forest Knolls, CA
  11. 2.2 2km E of Pacheco, CA
  12. 2.5 4km N of San Leandro, CA
  13. 1.8 1km NE of San Ramon, CA
  14. 2.0 1km W of Kensington, CA
  15. 2.5 1km W of Kensington, 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 3,000 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.