QuakeIndex

Earthquake · reviewed by a seismologist

M 1.9md

8 km SW of Mountain House, CA

· 17 km deep · released about 24 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Alameda County 29 kmSan Joaquin County 37 kmContra Costa County 37 kmStanislaus County 56 kmSanta Clara County 57 kmSolano County 67 kmSan Mateo County 77 kmSacramento County 83 kmSanta Cruz County 88 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
17 km below the surface
Felt
no reports yet
Nearest
Alameda County, 29 km WSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 534 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 24 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 5.8 640,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 450,000× the energy of this one
  3. Around the size people start to feel M 3.0 40× the energy of this one
  4. This earthquake M 1.9 about 24 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 37.7307, -121.5998. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Alameda County, CA 29 km (18 mi) ENE of here earthquakes near Alameda County
San Joaquin County, CA 37 km (23 mi) SW of here earthquakes near San Joaquin County
Contra Costa County, CA 37 km (23 mi) SE of here earthquakes near Contra Costa County
Stanislaus County, CA 56 km (35 mi) WNW of here earthquakes near Stanislaus County
Santa Clara County, CA 57 km (36 mi) N of here earthquakes near Santa Clara County
Solano County, CA 67 km (41 mi) SSE of here earthquakes near Solano County

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

Aftershocks so far

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

  1. 1.7 5 km WSW of Antioch, CA
  2. 2.0 6 km SSE of Moraga, CA
  3. 1.6 6 km SW of Clayton, CA
  4. 1.6 1 km NNW of Pleasant Hill, CA
  5. 1.9 1 km E of Hayward, CA
  6. 2.0 9 km ENE of Milpitas, CA
  7. 1.9 14 km SE of Alum Rock, CA
  8. 1.7 11 km ESE of Alum Rock, CA
  9. 1.9 11 km SSE of Livermore, CA
  10. 2.0 2 km SSE of Danville, CA
  11. 1.6 3 km SW of Clayton, CA
  12. 1.7 3 km SW of Clayton, CA
  13. 1.6 2 km NNW of Walnut Creek, CA
  14. 2.5 2 km NW of Walnut Creek, CA
  15. 1.9 3 km ESE of Hayward, 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 5.1 on 2022-10-25 — it released about 50,000 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.