QuakeIndex

mining explosion · reviewed by a seismologist

M 3.2ml

Earthquake near Sheridan, WY

USGS: 33 km WSW of Birney, Montana

1:57 pm MDT, Mar 15, 2021 · · 0.0 km deep · released about 1,900 lb of TNT

Every earthquake near Sheridan Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Sheridan County 44 kmBig Horn County 55 kmPowder River County 107 kmRosebud County 112 kmBig Horn County 113 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
1:57 pm MDT on 15 March 2021 ()
Where
43 km (27 mi) N of Sheridan, WY · earthquakes near Sheridan
Magnitude
M 3.2 (ml)
Depth
0.0 km below the surface
Felt
no reports yet
Nearest
Sheridan County, 44 km S
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1955 days ago

A magnitude 3.2 earthquake was recorded 43 km (27 mi) N of Sheridan, WY, at 1:57 pm MDT on 15 March 2021 (19:57 UTC). This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

USGS catalogues this as mining explosion, not an earthquake.

How big was it?

This earthquake released about 1,900 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.2 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 180,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 7,900× the energy of this one
  3. Magna, Utah 2020 M 5.7 5,600× the energy of this one
  4. This earthquake M 3.2 about 1,900 lb of TNT
  5. Around the size people start to feel M 3.0 this one released 2× 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

No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.

Before 2016, the USGS record since 1900 lists no earthquake of M5 or more within 50 km.

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 45.1785, -106.8898. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Sheridan County, WY 44 km (27 mi) S earthquakes near Sheridan County
Big Horn County, MT 55 km (34 mi) WNW earthquakes near Big Horn County
Powder River County, MT 107 km (67 mi) ENE earthquakes near Powder River County
Rosebud County, MT 112 km (70 mi) N earthquakes near Rosebud County
Big Horn County, WY 113 km (70 mi) SW earthquakes near Big Horn County
Treasure County, MT 120 km (75 mi) NNW earthquakes near Treasure County

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

Aftershocks so far

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

  1. 2.7 32 km NE of Ranchester, Wyoming
  2. 3.4 30 km NE of Ranchester, Wyoming
  3. 2.8 31 km NE of Ranchester, Wyoming
  4. 3.4 30 km NE of Ranchester, Wyoming
  5. 2.7 31 km NNE of Sheridan, Wyoming
  6. 3.3 23 km WSW of Birney, Montana
  7. 3.4 31 km NNE of Ranchester, Wyoming
  8. 3.0 32 km SW of Birney, Montana
  9. 3.0 33 km SW of Birney, Montana
  10. 2.9 32 km SSW of Birney, Montana
  11. 2.9 17 km WSW of Birney, Montana
  12. 2.9 34 km SW of Birney, Montana
  13. 2.9 30 km SW of Birney, Montana
  14. 3.2 31 km WSW of Birney, Montana
  15. 2.6 33 km WSW of Birney, Montana

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.