QuakeIndex

Earthquake · reviewed by a seismologist

M 2.3md

14km S of Groveland-Big Oak Flat, CA

· 25 km deep · released about 85 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Mariposa County 32 kmTuolumne County 40 kmCalaveras County 60 kmMadera County 70 kmStanislaus County 71 kmMerced County 73 kmAmador County 89 kmSan Joaquin County 95 kmAlpine County 107 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 2.3 (md)
Depth
25 km below the surface
Felt
3 reports · strongest reported intensity II
Nearest
Mariposa County, 32 km ESE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2524 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage. 3 people have reported feeling it to USGS.

How big was it?

This earthquake released about 85 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.3 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 180,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 130,000× the energy of this one
  3. Around the size people start to feel M 3.0 11× the energy of this one
  4. This earthquake M 2.3 about 85 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 37.7210, -120.2202. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Mariposa County, CA 32 km (20 mi) WNW of here earthquakes near Mariposa County
Tuolumne County, CA 40 km (25 mi) SW of here earthquakes near Tuolumne County
Calaveras County, CA 60 km (37 mi) SSE of here earthquakes near Calaveras County
Madera County, CA 70 km (44 mi) NW of here earthquakes near Madera County
Stanislaus County, CA 71 km (44 mi) ENE of here earthquakes near Stanislaus County
Merced County, CA 73 km (46 mi) NE of here earthquakes near Merced County

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

Aftershocks so far

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

  1. 2.1 19km SSW of Mariposa, CA
  2. 2.0 17km SSW of Bootjack, CA
  3. 2.5 18km SSW of Mariposa, CA
  4. 1.5 14km SSW of Mariposa, CA
  5. 2.1 11km E of Groveland-Big Oak Flat, CA
  6. 2.1 18km SSW of Mariposa, CA
  7. 1.9 1km SW of Mariposa, CA
  8. 1.6 14km SW of Bootjack, CA
  9. 2.1 12km WNW of Midpines, CA
  10. 2.1 14km NW of Midpines, CA
  11. 1.8 13km S of Mariposa, CA
  12. 2.6 14km S of Mariposa, CA
  13. 1.6 13km S of Mariposa, CA
  14. 1.6 19km SSW of Bootjack, CA
  15. 2.3 16km SSW of Bootjack, 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.