QuakeIndex

Earthquake · reviewed by a seismologist

M 2.3md

Earthquake near Oakhurst, CA

No earthquake was likely felt in Oakhurst in the 24 hours to 12:18 pm PST (20:18 UTC). The last one was M 5.7, 230 km (143 mi) NNE, at 6:29 pm PDT on 13 April 2026, estimated intensity II (weak) in town; 6,515 felt reports to USGS. Every earthquake near Oakhurst

This page: a magnitude 2.3 earthquake was recorded 29 km (18 mi) northeast of Oakhurst, CA, at 9:23 pm PDT on 18 August 2021 (04:23 UTC), 10 km deep.

USGS: 29km NE of Oakhurst, CA

86 km (53 mi) NNE of Fresno, CA

9:23 pm PDT, Aug 18, 2021 · · 10 km deep · released about 77 lb of TNT

10 km30 km60 km120 km N Madera County 44 kmMariposa County 47 kmMono County 66 kmTuolumne County 78 kmFresno County 84 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
9:23 pm PDT on 18 August 2021 ()
Where
29 km (18 mi) northeast of Oakhurst, CA · earthquakes near Oakhurst
Magnitude
M 2.3 (md)
Depth
10 km below the surface
Felt
no reports yet
Nearest
Madera County, 44 km SW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1907 days ago

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

At this magnitude and depth, people at rest would likely notice it out to about 16 km (10 mi) from the epicentre. In Oakhurst, 29 km away, the estimate is intensity II (weak). Estimated from magnitude, depth and distance with the intensity equation USGS Did You Feel It? uses; felt reports, where there are any, are the measurement.

How big was it?

This earthquake released about 77 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 5.8 200,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 140,000× the energy of this one
  3. Around the size people start to feel M 3.0 12× the energy of this one
  4. This earthquake M 2.3 about 77 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.

For this area

The largest earthquake within 50 km since 2016 was M 4.0 on 2020-04-05 — about 470 times the energy of this one.

Before 2016, the USGS record lists 9 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.0 7 km ENE of Mammoth Lakes, California · 48 km ENE of this epicentre
  2. 5.9 8 km NNE of Mammoth Lakes, California · 48 km ENE of this epicentre
  3. 5.9 11 km SE of Mammoth Lakes, California · 48 km ENE of this epicentre
  4. 5.7 14 km WSW of Aspen Springs, California · 45 km E of this epicentre
  5. 5.4 12 km SE of Mammoth Lakes, California · 46 km E of this epicentre

Since 2016: the QuakeIndex catalogue (US, M1.5+), built from the USGS FDSN event service. Before 2016: USGS ComCat, M5+ from 1900. Distances are between epicentres. This is the record, not a forecast.

Where

Epicentre 37.4835, -119.3895. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Madera County, CA 44 km (27 mi) SW earthquakes near Madera County
Mariposa County, CA 47 km (29 mi) WNW earthquakes near Mariposa County
Mono County, CA 66 km (41 mi) NE earthquakes near Mono County
Tuolumne County, CA 78 km (49 mi) NW earthquakes near Tuolumne County
Fresno County, CA 84 km (52 mi) SSW earthquakes near Fresno County
Merced County, CA 122 km (76 mi) WSW earthquakes near Merced County

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

Aftershocks so far

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

  1. 2.1 19km SE of Yosemite Valley, CA
  2. 1.8 20km SE of Yosemite Valley, CA
  3. 1.7 16km WSW of Toms Place, CA
  4. 2.3 17km WSW of Toms Place, CA
  5. 1.9 17km WSW of Toms Place, CA
  6. 2.5 16km WSW of Toms Place, CA
  7. 2.0 30km ENE of Shaver Lake, CA
  8. 1.6 17km WSW of Toms Place, CA
  9. 1.8 29km NE of Oakhurst, CA
  10. 1.6 17km WSW of Mammoth Lakes, CA
  11. 1.9 30km NE of Oakhurst, CA
  12. 2.4 17km WSW of Mammoth Lakes, CA
  13. 1.5 32km ENE of Shaver Lake, CA
  14. 1.6 7km ENE of Mammoth Lakes, CA
  15. 2.1 0km SW of Yosemite Lakes, 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.