QuakeIndex

Earthquake · reviewed by a seismologist

M 2.2md

Earthquake near Blackhawk, CA

Yes. A magnitude 2.2 earthquake was recorded 7 km (5 mi) E of Blackhawk, CA, at 9:34 pm PDT on 18 October 2016 (04:34 UTC), 12 km deep. 2 people have reported feeling it to USGS.

This was on 18 October 2016. The latest near Blackhawk: M 3.0 on 14 September 2026.

USGS: 7 km E of Blackhawk, California

12 km (7 mi) NE of San Ramon, CA · 59 km (37 mi) N of San Jose, CA

9:34 pm PDT, Oct 18, 2016 · · 12 km deep · released about 69 lb of TNT

Every earthquake near Blackhawk Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Contra Costa County 15 kmAlameda County 22 kmSolano County 50 kmSan Joaquin County 50 kmSan Mateo County 67 kmSanta Clara County 69 kmStanislaus County 78 kmSacramento County 81 kmMarin County 85 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
9:34 pm PDT on 18 October 2016 ()
Where
7 km (5 mi) E of Blackhawk, CA · earthquakes near Blackhawk
Magnitude
M 2.2 (md)
Depth
12 km below the surface
Felt
2 reports · strongest reported intensity II
Nearest
Contra Costa County, 15 km NW
Nearest mapped fault
Greenville fault, 1 km from its surface trace — near is not the same as on
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3531 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth, people at rest would likely notice it out to about 14 km (9 mi) from the epicentre. In Blackhawk, 7 km away, the estimate is intensity II (weak). Estimated from magnitude, depth and distance with the intensity equation USGS Did You Feel It? uses; felt reports, where there are any, are the measurement.

Likely felt in: Blackhawk 7 km, intensity II · Diablo 12 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 69 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.2 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 220,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 150,000× the energy of this one
  3. Around the size people start to feel M 3.0 14× the energy of this one
  4. This earthquake M 2.2 about 69 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.

For this area

No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.

Before 2016, the USGS record lists 6 earthquakes of M5 or more within 50 km; the five largest:

  1. 5.8 The 1980 Livermore, California Earthquake · 5 km ENE of this epicentre
  2. 5.7 15 km NE of East Foothills, California · 41 km SSE of this epicentre
  3. 5.5 6 km NNE of East Foothills, California · 44 km S of this epicentre
  4. 5.4 9 km NE of Livermore, California · 14 km SE of this epicentre
  5. 5.3 6 km E of East Foothills, California · 49 km S of this epicentre

Since 2016: the QuakeIndex catalogue (US, M1.5+), built from the USGS FDSN event service. Before 2016: USGS ComCat, M5+ from 1900. Distances are between epicentres. This is the record, not a forecast.

Where

Epicentre 37.8287, -121.8237. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Contra Costa County, CA 15 km (9 mi) NW earthquakes near Contra Costa County
Alameda County, CA 22 km (13 mi) SSW earthquakes near Alameda County
Solano County, CA 50 km (31 mi) NNW earthquakes near Solano County
San Joaquin County, CA 50 km (31 mi) ENE earthquakes near San Joaquin County
San Mateo County, CA 67 km (41 mi) SW earthquakes near San Mateo County
Santa Clara County, CA 69 km (43 mi) S earthquakes near Santa Clara County

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

Aftershocks so far

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

  1. 1.5 0 km NW of Concord, California
  2. 1.8 5 km NE of East Foothills, California
  3. 2.6 Northern California
  4. 2.1 6 km E of East Foothills, California
  5. 1.6 1 km S of Pacheco, California
  6. 2.2 1 km E of Pacheco, California
  7. 1.9 9 km S of Antioch, California
  8. 2.5 3 km NNW of Piedmont, California
  9. 1.7 20 km SE of Livermore, California
  10. 1.7 1 km E of North Gate, California
  11. 1.6 8 km NE of Milpitas, California
  12. 1.6 6 km ENE of East Foothills, California
  13. 1.8 9 km ENE of Blackhawk, California
  14. 1.7 5 km SW of Alamo, California
  15. 1.6 1 km SSW of Concord, California

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.

On USGS

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.