QuakeIndex

Earthquake · reviewed by a seismologist

M 1.9md

2km SSW of Pleasant Hill, CA

· 12 km deep · released about 23 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Contra Costa County 10 kmAlameda County 34 kmSolano County 39 kmMarin County 61 kmSan Mateo County 64 kmNapa County 68 kmSan Joaquin County 70 kmYolo County 84 kmSacramento 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
Magnitude
M 1.9 (md)
Depth
12 km below the surface
Felt
no reports yet
Nearest
Contra Costa County, 10 km E
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2486 days ago

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

How big was it?

This earthquake released about 23 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.9 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 660,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 470,000× the energy of this one
  3. Around the size people start to feel M 3.0 42× the energy of this one
  4. This earthquake M 1.9 about 23 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 37.9323, -122.0648. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Contra Costa County, CA 10 km (6 mi) W of here earthquakes near Contra Costa County
Alameda County, CA 34 km (21 mi) NNW of here earthquakes near Alameda County
Solano County, CA 39 km (24 mi) SSW of here earthquakes near Solano County
Marin County, CA 61 km (38 mi) ESE of here earthquakes near Marin County
San Mateo County, CA 64 km (40 mi) NNE of here earthquakes near San Mateo County
Napa County, CA 68 km (42 mi) SSE of here earthquakes near Napa 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. 2.0 12km SW of Byron, CA
  2. 1.7 1km NE of Diablo, CA
  3. 2.1 1km NE of Diablo, CA
  4. 1.8 0km E of Diablo, CA
  5. 1.5 0km E of Diablo, CA
  6. 1.5 2km WNW of Concord, CA
  7. 1.7 3km ENE of San Ramon, CA
  8. 1.6 3km NNE of Green Valley, CA
  9. 1.9 2km SE of Pacheco, CA
  10. 1.7 5km NW of Sunol, CA
  11. 2.1 2km NW of Concord, CA
  12. 1.8 1km ESE of Pacheco, CA
  13. 1.9 2km NNE of San Ramon, CA
  14. 2.2 1km SW of Danville, CA
  15. 1.9 4km N of Diablo, 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 6,500 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.