QuakeIndex

Earthquake · reviewed by a seismologist

M 3.1ml

Earthquake near Mammoth Lakes, CA

No earthquake was likely felt in Mammoth Lakes in the 24 hours to 3:36 pm PST (23:36 UTC). The last one was M 2.9, 26 km (16 mi) SSE, at 3:54 am PDT on 24 October 2026, estimated intensity II (weak) in town. Every earthquake near Mammoth Lakes

This page: a magnitude 3.1 earthquake was recorded 46 km (29 mi) northeast of Mammoth Lakes, CA, at 3:33 pm PDT on 21 March 2021 (22:33 UTC), 6.2 km deep. 4 people have reported feeling it to USGS.

USGS: 39km NNE of Toms Place, CA

3:33 pm PDT, Mar 21, 2021 · · 6.2 km deep · released about 1,300 lb of TNT

Every earthquake near Mammoth Lakes Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Mono County 28 kmMineral County 70 kmEsmeralda County 82 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
3:33 pm PDT on 21 March 2021 ()
Where
46 km (29 mi) northeast of Mammoth Lakes, CA · earthquakes near Mammoth Lakes
Magnitude
M 3.1 (ml)
Depth
6.2 km below the surface
Felt
4 reports · strongest reported intensity II
Measured shaking
intensity III (ShakeMap)
Nearest
Mono County, 28 km W
Nearest mapped fault
White Mountains fault, 5 km from its surface trace — near is not the same as on
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1557 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

At this magnitude and depth, people at rest would likely notice it out to about 40 km (25 mi) from the epicentre. In Mammoth Lakes, 46 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 1,300 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.1 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 270,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 12,000× the energy of this one
  3. Magna, Utah 2020 M 5.7 8,500× the energy of this one
  4. This earthquake M 3.1 about 1,300 lb of TNT
  5. Around the size people start to feel M 3.0 this one released 1.3× more

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 5.2 on 2020-04-11 — about 1,700 times the energy of this one.

Before 2016, the USGS record lists 58 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.4 The 1986 Chalfant Valley, California Earthquake · 41 km SSE of this epicentre
  2. 6.3 The 1934 Excelsior Mountains, Nevada Earthquake · 46 km NNE of this epicentre
  3. 6.2 9 km SW of Aspen Springs, California · 49 km SSW of this epicentre
  4. 6.1 Near Tonopah Junction, Nevada · 50 km ENE of this epicentre
  5. 6.1 11 km WNW of Aspen Springs, California · 42 km SW 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 37.8967, -118.5543. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Mono County, CA 28 km (18 mi) W earthquakes near Mono County
Mineral County, NV 70 km (43 mi) N earthquakes near Mineral County
Esmeralda County, NV 82 km (51 mi) E earthquakes near Esmeralda County
Mariposa County, CA 125 km (77 mi) WSW earthquakes near Mariposa County
Madera County, CA 130 km (81 mi) SW earthquakes near Madera County
Alpine County, CA 135 km (84 mi) NW earthquakes near Alpine County

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

Aftershocks so far

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

  1. 1.6 38km NNE of Toms Place, CA
  2. 1.8 31km SSW of Qualeys Camp, NV
  3. 1.6 25 km S of Mina, Nevada
  4. 1.6 29 km N of Dyer, Nevada
  5. 2.1 41km NNE of Toms Place, CA
  6. 1.5 26 km SSW of Mina, Nevada
  7. 1.6 7 km NE of Lee Vining, California
  8. 1.7 California-Nevada border region
  9. 1.6 38km NNE of Toms Place, CA
  10. 1.6 39km NNE of Toms Place, CA
  11. 1.9 40km NNE of Toms Place, CA
  12. 1.7 39km NNE of Toms Place, CA
  13. 2.1 27 km SSW of Mina, Nevada
  14. 2.8 39km NNE of Toms Place, CA
  15. 2.8 28 km SSW of Mina, Nevada

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.