QuakeIndex

Earthquake · reviewed by a seismologist

M 2.1md

11km E of Groveland-Big Oak Flat, CA

· 38 km deep · released about 46 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Tuolumne County 24 kmMariposa County 32 kmCalaveras County 58 kmMadera County 75 kmAmador County 85 kmStanislaus County 86 kmMerced County 91 kmAlpine County 91 kmSan Joaquin County 105 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
38 km below the surface
Felt
no reports yet
Nearest
Tuolumne County, 24 km NNE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1854 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 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 37.8297, -120.0797. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Tuolumne County, CA 24 km (15 mi) SSW of here earthquakes near Tuolumne County
Mariposa County, CA 32 km (20 mi) NNW of here earthquakes near Mariposa County
Calaveras County, CA 58 km (36 mi) SE of here earthquakes near Calaveras County
Madera County, CA 75 km (46 mi) NNW of here earthquakes near Madera County
Amador County, CA 85 km (53 mi) SE of here earthquakes near Amador County
Stanislaus County, CA 86 km (54 mi) ENE of here earthquakes near Stanislaus County

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

Aftershocks so far

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

  1. 2.1 11 km SSW of Mariposa, CA
  2. 2.2 9 km NW of Chinese Camp, CA
  3. 2.2 11 km SSW of Mariposa, CA
  4. 1.6 8 km SSW of Mariposa, CA
  5. 2.2 10 km SSW of Mariposa, CA
  6. 2.1 20 km ENE of Mi-Wuk Village, CA
  7. 2.3 15 km SW of Mariposa, CA
  8. 2.4 9 km SSW of Mariposa, CA
  9. 2.4 7 km SSW of Mariposa, CA
  10. 2.3 10 km SSW of Mariposa, CA
  11. 2.3 10 km SSW of Mariposa, CA
  12. 2.0 10 km SSW of Mariposa, CA
  13. 2.3 11 km SSW of Mariposa, CA
  14. 2.8 10 km SSW of Mariposa, CA
  15. 2.0 9 km SSW of Mariposa, 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.

On USGS

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