QuakeIndex

Earthquake · reviewed by a seismologist

M 2.7ml

Earthquake near Dillon, MT

No earthquake was likely felt in Dillon in the 24 hours to 2:43 pm MST (21:43 UTC). The last one was M 2.0, 14 km (9 mi) N, at 2:45 pm MDT on 7 May 2026, estimated intensity II (weak) in town. Every earthquake near Dillon

This page: a magnitude 2.7 earthquake was recorded 24 km (15 mi) east-southeast of Dillon, MT, at 11:11 pm MST on 23 February 2021 (06:11 UTC), 7.2 km deep.

USGS: 23 km ESE of Dillon, Montana

11:11 pm MST, Feb 23, 2021 · · 7.2 km deep · released about 340 lb of TNT

10 km30 km60 km120 km N Madison County 39 kmBeaverhead County 43 kmSilver Bow County 86 kmClark County 96 kmGallatin County 101 kmJefferson County 110 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
11:11 pm MST on 23 February 2021 ()
Where
24 km (15 mi) east-southeast of Dillon, MT · earthquakes near Dillon
Montana today
every earthquake in Montana in the last 24 hours
Magnitude
M 2.7 (ml)
Depth
7.2 km below the surface
Felt
no reports yet
Nearest
Madison County, 39 km ENE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2017 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 24 km (15 mi) from the epicentre. In Dillon, 24 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: Dillon 24 km, intensity II. Estimated for each town centre; each link is that town's own record.

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. 5.6 16 km N of Dillon, Montana · 31 km NW 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 45.1530, -112.3505. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Madison County, MT 39 km (24 mi) ENE earthquakes near Madison County
Beaverhead County, MT 43 km (26 mi) W earthquakes near Beaverhead County
Silver Bow County, MT 86 km (53 mi) NNW earthquakes near Silver Bow County
Clark County, ID 96 km (60 mi) S earthquakes near Clark County
Gallatin County, MT 101 km (63 mi) ENE earthquakes near Gallatin County
Jefferson County, MT 110 km (69 mi) NNE earthquakes near Jefferson County

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

Aftershocks so far

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

  1. 1.8 3 km NNW of Alder, Montana
  2. 1.9 23 km SSE of Dillon, Montana
  3. 1.9 17 km N of Dillon, Montana
  4. 2.3 34 km S of Virginia City, Montana
  5. 1.9 8 km ESE of Sheridan, Montana
  6. 1.8 14 km N of Dillon, Montana
  7. 1.6 41 km S of Virginia City, Montana
  8. 2.1 32 km S of Virginia City, Montana
  9. 2.3 13 km NNE of Dillon, Montana
  10. 1.6 26 km NW of Lima, Montana
  11. 2.1 47 km ENE of Lima, Montana
  12. 2.0 33 km NNW of Lima, Montana
  13. 1.5 3 km ESE of Twin Bridges, Montana
  14. 2.7 26 km SSE of Virginia City, Montana
  15. 2.1 17 km NNE of Dillon, 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.