QuakeIndex

Earthquake · reviewed by a seismologist

M 2.1md

1km WNW of Kensington, CA

· 4.4 km deep · released about 47 lb of TNT

10 km30 km60 km120 km N Contra Costa County 30 kmMarin County 43 kmAlameda County 45 kmSolano County 50 kmSan Mateo County 56 kmNapa County 66 kmSan Francisco County 68 kmSonoma County 88 kmSan Joaquin County 90 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
4.4 km below the surface
Felt
43 reports · strongest reported intensity III
Nearest
Contra Costa County, 30 km E
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1419 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage. 43 people have reported feeling it to USGS.

How big was it?

This earthquake released about 47 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 5.8 320,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 230,000× the energy of this one
  3. Around the size people start to feel M 3.0 20× the energy of this one
  4. This earthquake M 2.1 about 47 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 37.9133, -122.2937. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Contra Costa County, CA 30 km (19 mi) W of here earthquakes near Contra Costa County
Marin County, CA 43 km (26 mi) ESE of here earthquakes near Marin County
Alameda County, CA 45 km (28 mi) NW of here earthquakes near Alameda County
Solano County, CA 50 km (31 mi) SW of here earthquakes near Solano County
San Mateo County, CA 56 km (35 mi) N of here earthquakes near San Mateo County
Napa County, CA 66 km (41 mi) S of here earthquakes near Napa County

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

Aftershocks so far

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

  1. 1.6 2km S of San Ramon, CA
  2. 1.9 3km E of Hayward, CA
  3. 2.0 2km ESE of Berkeley, CA
  4. 1.7 5km SE of Point Reyes Station, CA
  5. 1.5 6km WNW of Sunol, CA
  6. 2.2 4km WSW of Colma, CA
  7. 1.8 5km WSW of Colma, CA
  8. 1.8 2km SE of Pacheco, CA
  9. 1.5 2km SE of Pacheco, CA
  10. 1.7 2km N of San Leandro, CA
  11. 1.5 8km SSW of Brentwood, CA
  12. 2.0 2km NE of Danville, CA
  13. 1.9 2km W of Diablo, CA
  14. 1.9 2km NE of Danville, CA
  15. 1.7 9km NE of Blackhawk, 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 3,100 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.