QuakeIndex

chemical explosion · reviewed by a seismologist

M 2.1md

8km WSW of Mountain House, CA

· -0.3 km deep · released about 46 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Alameda County 27 kmContra Costa County 33 kmSan Joaquin County 37 kmStanislaus County 59 kmSanta Clara County 60 kmSolano County 63 kmSan Mateo County 75 kmSacramento County 81 kmSanta Cruz 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
-0.3 km below the surface
Felt
1 report · strongest reported intensity II
Nearest
Alameda County, 27 km WSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2631 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage. 1 person has reported feeling it to USGS.

USGS catalogues this as chemical explosion, not an earthquake.

How big was it?

This earthquake released about 46 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 5.8 330,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 230,000× the energy of this one
  3. Around the size people start to feel M 3.0 21× the energy of this one
  4. This earthquake M 2.1 about 46 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 37.7565, -121.6325. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Alameda County, CA 27 km (17 mi) ENE of here earthquakes near Alameda County
Contra Costa County, CA 33 km (21 mi) ESE of here earthquakes near Contra Costa County
San Joaquin County, CA 37 km (23 mi) WSW of here earthquakes near San Joaquin County
Stanislaus County, CA 59 km (37 mi) WNW of here earthquakes near Stanislaus County
Santa Clara County, CA 60 km (37 mi) N of here earthquakes near Santa Clara County
Solano County, CA 63 km (39 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

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

  1. 2.2 4km N of Dublin, CA
  2. 2.8 4km N of Dublin, CA
  3. 1.8 4km NNE of Dublin, CA
  4. 1.6 4km NNE of Dublin, CA
  5. 2.6 4km NNE of Dublin, CA
  6. 1.6 3km SW of Clayton, CA
  7. 2.3 3km NE of Orinda, CA
  8. 1.6 4km N of Dublin, CA
  9. 1.6 4km NNE of Dublin, CA
  10. 1.6 4km NNE of Dublin, CA
  11. 2.0 4km N of Dublin, CA
  12. 1.9 4km N of Dublin, CA
  13. 1.8 4km NNE of Dublin, CA
  14. 1.7 4km N of Dublin, CA
  15. 2.0 4km N of Dublin, 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 4.1 on 2017-10-10 — it released about 900 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.