QuakeIndex

Earthquake · reviewed by a seismologist

M 2.0md

7km SE of Blackhawk, CA

· 20 km deep · released about 26 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Alameda County 16 kmContra Costa County 18 kmSan Joaquin County 53 kmSolano County 55 kmSan Mateo County 62 kmSanta Clara County 64 kmStanislaus County 78 kmMarin County 85 kmSacramento County 86 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 2.0 (md)
Depth
20 km below the surface
Felt
3 reports · strongest reported intensity II
Nearest
Alameda County, 16 km SSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2329 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage. 3 people have reported feeling it to USGS.

How big was it?

This earthquake released about 26 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.0 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 580,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 410,000× the energy of this one
  3. Around the size people start to feel M 3.0 36× the energy of this one
  4. This earthquake M 2.0 about 26 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 37.7827, -121.8392. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Alameda County, CA 16 km (10 mi) NNE of here earthquakes near Alameda County
Contra Costa County, CA 18 km (11 mi) SSE of here earthquakes near Contra Costa County
San Joaquin County, CA 53 km (33 mi) WSW of here earthquakes near San Joaquin County
Solano County, CA 55 km (34 mi) S of here earthquakes near Solano County
San Mateo County, CA 62 km (39 mi) NE of here earthquakes near San Mateo County
Santa Clara County, CA 64 km (40 mi) NNW of here earthquakes near Santa Clara County

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

Aftershocks so far

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

  1. 2.5 11km SSW of Brentwood, CA
  2. 2.6 11km ENE of Milpitas, CA
  3. 1.8 9km NNE of Milpitas, CA
  4. 2.2 10km NE of Milpitas, CA
  5. 2.3 9km NE of Blackhawk, CA
  6. 2.2 6km E of Alum Rock, CA
  7. 1.8 1km WNW of Kensington, CA
  8. 1.8 7km N of Orinda, CA
  9. 1.9 5km ENE of Vallejo, CA
  10. 1.5 4km WSW of Brentwood, CA
  11. 2.1 10km SW of Brentwood, CA
  12. 1.5 1km SSE of Pleasanton, CA
  13. 1.6 14km SE of Livermore, CA
  14. 1.9 2km NNE of Alameda, CA
  15. 1.9 1km NW of Pleasant Hill, 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 5,600 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.