QuakeIndex

mining explosion · reviewed by a seismologist

M 2.7ml

Earthquake near Gillette, WY

No earthquake was likely felt in Gillette in the 24 hours to 3:49 pm MST (22:49 UTC). The last one was M 3.4, 45 km (28 mi) SSE, at 2:13 pm MDT on 6 July 2026, estimated intensity II (weak) in town. Every earthquake near Gillette

No: USGS classifies this as a mining explosion, not an earthquake. A magnitude 2.7 mining explosion was recorded 5 km (3 mi) west of Gillette, WY, at 4:48 pm MDT on 12 March 2023 (22:48 UTC), less than 1 km deep.

USGS: 5 km W of Gillette, Wyoming

4:48 pm MDT, Mar 12, 2023 · · 0.0 km deep · released about 340 lb of TNT

10 km30 km60 km120 km N Campbell County 12 kmJohnson County 86 kmCrook County 86 kmWeston County 94 kmSheridan County 117 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
4:48 pm MDT on 12 March 2023 ()
Where
5 km (3 mi) west of Gillette, WY · earthquakes near Gillette
Magnitude
M 2.7 (ml)
Depth
0.0 km below the surface
Felt
no reports yet
Nearest
Campbell County, 12 km SSE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1271 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 25 km (16 mi) from the epicentre. In Gillette, 5 km away, the estimate is intensity III (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.

Earthquakes near other towns within 30 km: Antelope Valley-Crestview, Sleepy Hollow.

USGS catalogues this as mining explosion, not an earthquake.

How big was it?

This earthquake released about 340 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.7 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 45,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 32,000× the energy of this one
  3. Around the size people start to feel M 3.0 2.8× the energy of this one
  4. This earthquake M 2.7 about 340 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

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

Before 2016, the USGS record lists one earthquake of M5 or more within 50 km:

  1. 5.0 37 km W of Gillette, Wyoming · 32 km WSW 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 44.2936, -105.5711. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Campbell County, WY 12 km (8 mi) SSE earthquakes near Campbell County
Johnson County, WY 86 km (53 mi) WSW earthquakes near Johnson County
Crook County, WY 86 km (54 mi) ENE earthquakes near Crook County
Weston County, WY 94 km (59 mi) ESE earthquakes near Weston County
Sheridan County, WY 117 km (73 mi) WNW earthquakes near Sheridan County

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

Aftershocks so far

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

  1. 3.4 21 km NE of Wright, Wyoming
  2. 2.9 0 km W of Antelope Valley-Crestview, Wyoming
  3. 3.0 4 km NNW of Sleepy Hollow, Wyoming
  4. 2.8 4 km ESE of Gillette, Wyoming
  5. 3.1 18 km SSE of Sleepy Hollow, Wyoming
  6. 3.0 8 km E of Sleepy Hollow, Wyoming
  7. 2.9 26 km S of Antelope Valley-Crestview, Wyoming
  8. 2.7 20 km SSE of Antelope Valley-Crestview, Wyoming
  9. 2.9 19 km N of Gillette, Wyoming
  10. 2.6 6 km NE of Gillette, Wyoming
  11. 3.2 20 km SSE of Antelope Valley-Crestview, Wyoming
  12. 2.9 17 km NNE of Wright, Wyoming
  13. 2.4 7 km SSE of Antelope Valley-Crestview, Wyoming
  14. 2.6 6 km NW of Gillette, Wyoming
  15. 2.7 29 km NE of Wright, 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

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.