QuakeIndex

mining explosion · reviewed by a seismologist

M 3.5ml

Earthquake near Lusk, WY

No earthquake was likely felt in Lusk in the 24 hours to 8:06 pm MST (03:06 UTC). The last one was M 2.6, 46 km (29 mi) WSW, at 3:31 am MDT on 28 May 2025, estimated intensity II (weak) in town. Every earthquake near Lusk

No: USGS classifies this as a mining explosion, not an earthquake. A magnitude 3.5 mining explosion was recorded 21 km (13 mi) west-southwest of Lusk, WY, at 4:07 pm MDT on 27 September 2019 (22:07 UTC), less than 1 km deep.

USGS: 9 km SW of Manville, Wyoming

4:07 pm MDT, Sep 27, 2019 · · 0.0 km deep · released about 2.7 tons of TNT

10 km30 km60 km120 km N Niobrara County 43 kmPlatte County 69 kmConverse County 73 kmGoshen County 76 kmSioux County 85 kmFall River County 112 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
4:07 pm MDT on 27 September 2019 ()
Where
21 km (13 mi) west-southwest of Lusk, WY · earthquakes near Lusk
Magnitude
M 3.5 (ml)
Depth
0.0 km below the surface
Felt
no reports yet
Nearest
Niobrara County, 43 km NNE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2518 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 306 km (190 mi) from the epicentre. In Lusk, 21 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.

USGS catalogues this as mining explosion, not an earthquake.

How big was it?

This earthquake released about 2.7 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.5 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 63,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 2,800× the energy of this one
  3. Magna, Utah 2020 M 5.7 2,000× the energy of this one
  4. This earthquake M 3.5 about 2.7 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 5.6× 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 42.7217, -104.7070. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Niobrara County, WY 43 km (26 mi) NNE earthquakes near Niobrara County
Platte County, WY 69 km (43 mi) SSW earthquakes near Platte County
Converse County, WY 73 km (45 mi) WNW earthquakes near Converse County
Goshen County, WY 76 km (47 mi) SSE earthquakes near Goshen County
Sioux County, NE 85 km (53 mi) ESE earthquakes near Sioux County
Fall River County, SD 112 km (70 mi) ENE earthquakes near Fall River County

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

Aftershocks so far

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

  1. 2.6 9 km ENE of Glendo, Wyoming
  2. 2.7 19 km ENE of Hartville, 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.