mining explosion · reviewed by a seismologist
M 3.2ml
Earthquake near Sheridan, WY
No earthquake was likely felt in Sheridan in the 24 hours to 3:03 pm MST (22:03 UTC). The last one was M 3.5, 40 km (25 mi) N, at 10:02 am MDT on 29 May 2026, estimated intensity II (weak) in town. Every earthquake near Sheridan
No: USGS classifies this as a mining explosion, not an earthquake. A magnitude 3.2 mining explosion was recorded 50 km (31 mi) north of Sheridan, WY, at 12:08 pm MDT on 23 August 2023 (18:08 UTC), less than 1 km deep.
USGS: 31 km WSW of Birney, Montana
- When
- 12:08 pm MDT on 23 August 2023 ()
- Where
- 50 km (31 mi) north of Sheridan, WY · earthquakes near Sheridan
- Montana today
- every earthquake in Montana in the last 24 hours
- Magnitude
- M 3.2 (ml)
- Depth
- 0.0 km below the surface
- Felt
- no reports yet
- Nearest
- Big Horn County, 51 km WNW
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 1110 days ago
Earthquake alerts for Sheridan, WY
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Not a warning. An alert comes after USGS publishes a quake, usually minutes after the shaking. For early warning use ShakeAlert, through your phone's Wireless Emergency Alerts or the MyShake app.
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 47 km (29 mi) from the epicentre. In Sheridan, 50 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.
Likely felt in: Lame Deer 46 km, intensity II. Estimated for each town centre; each link is that town's own record.
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.
- Northridge, California 1994 M 6.7 180,000× the energy of this one
- Mineral, Virginia 2011 M 5.8 7,900× the energy of this one
- Magna, Utah 2020 M 5.7 5,600× the energy of this one
- This earthquake M 3.2 about 1,900 lb of TNT
- 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 45.2453, -106.9061. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Big Horn County, MT | 51 km (32 mi) | WNW | earthquakes near Big Horn County |
| Sheridan County, WY | 52 km (32 mi) | S | earthquakes near Sheridan County |
| Rosebud County, MT | 105 km (65 mi) | N | earthquakes near Rosebud County |
| Powder River County, MT | 107 km (67 mi) | E | earthquakes near Powder River County |
| Treasure County, MT | 113 km (70 mi) | NNW | earthquakes near Treasure County |
| Big Horn County, WY | 117 km (73 mi) | SW | earthquakes near Big Horn County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
49 earthquakes have been recorded within 50 km since this one.
- 3.5 30 km NNE of Ranchester, Wyoming
- 3.5 31 km NE of Ranchester, Wyoming
- 2.6 29 km NE of Ranchester, Wyoming
- 2.6 26 km ENE of Ranchester, Wyoming
- 3.4 33 km NE of Ranchester, Wyoming
- 3.1 28 km NE of Ranchester, Wyoming
- 2.6 17 km NE of Ranchester, Wyoming
- 3.5 31 km NE of Ranchester, Wyoming
- 2.8 33 km NNE of Sheridan, Wyoming
- 3.5 33 km NE of Ranchester, Wyoming
- 2.9 28 km ENE of Ranchester, Wyoming
- 2.9 29 km NNE of Sheridan, Wyoming
- 3.0 31 km NNE of Sheridan, Wyoming
- 3.2 28 km NE of Ranchester, Wyoming
- 3.3 31 km NE of Ranchester, Wyoming
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
- The official USGS event page — the source of record for every value above
- Did you feel it? Report it to USGS — reports go to USGS, not to us
- ShakeMap for this event, when USGS has produced one
QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.