QuakeIndex

Earthquake · reviewed by a seismologist

M 2.1md

6km WNW of Dublin, CA

· 6.7 km deep · released about 44 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Alameda County 11 kmContra Costa County 21 kmSan Mateo County 49 kmSolano County 60 kmSanta Clara County 62 kmSan Joaquin County 67 kmMarin County 75 kmSanta Cruz County 80 kmStanislaus 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 2.1 (md)
Depth
6.7 km below the surface
Felt
18 reports · strongest reported intensity II
Nearest
Alameda County, 11 km SE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1948 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage. 18 people have reported feeling it to USGS.

How big was it?

This earthquake released about 44 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 5.8 340,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 240,000× the energy of this one
  3. Around the size people start to feel M 3.0 22× the energy of this one
  4. This earthquake M 2.1 about 44 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 37.7295, -121.9897. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Alameda County, CA 11 km (7 mi) NW of here earthquakes near Alameda County
Contra Costa County, CA 21 km (13 mi) S of here earthquakes near Contra Costa County
San Mateo County, CA 49 km (30 mi) NE of here earthquakes near San Mateo County
Solano County, CA 60 km (37 mi) S of here earthquakes near Solano County
Santa Clara County, CA 62 km (39 mi) NNW of here earthquakes near Santa Clara County
San Joaquin County, CA 67 km (42 mi) WSW of here earthquakes near San Joaquin 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. 2.1 8km ENE of Alum Rock, CA
  2. 2.0 1km NNW of Pleasant Hill, CA
  3. 2.1 15km ENE of Alum Rock, CA
  4. 2.4 5km SE of Portola Valley, CA
  5. 1.6 9km WSW of Mountain House, CA
  6. 1.5 2km ESE of Berkeley, CA
  7. 1.9 11km NE of Milpitas, CA
  8. 1.5 4km E of Moraga, CA
  9. 2.2 4km NNE of Blackhawk, CA
  10. 2.5 4km NNE of Blackhawk, CA
  11. 2.0 4km NE of Blackhawk, CA
  12. 1.9 4km SSW of Colma, CA
  13. 1.5 16km SSE of Livermore, CA
  14. 1.6 9km WSW of Mountain House, CA
  15. 2.3 2km WNW of Concord, 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 3,300 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.