QuakeIndex

Earthquake · reviewed by a seismologist

M 1.9ml

Earthquake near Dillon, MT

No earthquake was likely felt in Dillon in the 24 hours to 9:58 am MST (16:58 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 1.9 earthquake was recorded 48 km (30 mi) east-northeast of Dillon, MT, at 12:57 pm MDT on 29 April 2023 (18:57 UTC), 5.6 km deep.

USGS: 8 km ESE of Sheridan, Montana

12:57 pm MDT, Apr 29, 2023 · · 5.6 km deep · released about 22 lb of TNT

10 km30 km60 km120 km N Madison County 18 kmSilver Bow County 69 kmBeaverhead County 70 kmGallatin County 74 kmJefferson County 79 kmDeer Lodge County 111 kmBroadwater County 111 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
12:57 pm MDT on 29 April 2023 ()
Where
48 km (30 mi) east-northeast of Dillon, MT · earthquakes near Dillon
Montana today
every earthquake in Montana in the last 24 hours
Magnitude
M 1.9 (ml)
Depth
5.6 km below the surface
Felt
no reports yet
Nearest
Madison County, 18 km SE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1290 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth, people at rest would likely notice it out to about 14 km (9 mi) from the epicentre. In Dillon, 48 km away, the estimate is intensity I (not felt). 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.

How big was it?

This earthquake released about 22 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.9 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 680,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 480,000× the energy of this one
  3. Around the size people start to feel M 3.0 43× the energy of this one
  4. This earthquake M 1.9 about 22 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

The largest earthquake within 50 km since 2016 was M 4.0 on 2016-09-03 — about 1,500 times the energy of this one.

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

  1. 5.6 16 km N of Dillon, Montana · 41 km W 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 45.4185, -112.0977. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Madison County, MT 18 km (11 mi) SE earthquakes near Madison County
Silver Bow County, MT 69 km (43 mi) NW earthquakes near Silver Bow County
Beaverhead County, MT 70 km (43 mi) WSW earthquakes near Beaverhead County
Gallatin County, MT 74 km (46 mi) E earthquakes near Gallatin County
Jefferson County, MT 79 km (49 mi) N earthquakes near Jefferson County
Deer Lodge County, MT 111 km (69 mi) NW earthquakes near Deer Lodge County

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

Aftershocks so far

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

  1. 1.5 29 km SE of Virginia City, Montana
  2. 1.5 14 km E of Dillon, Montana
  3. 2.7 12 km E of Dillon, Montana
  4. 2.5 13 km E of Dillon, Montana
  5. 4.1 11 km E of Dillon, Montana
  6. 1.6 28 km S of Ennis, Montana
  7. 2.4 18 km NNE of Twin Bridges, Montana
  8. 1.6 34 km S of Virginia City, Montana
  9. 1.5 28 km SE of Virginia City, Montana
  10. 1.5 18 km W of Pony, Montana
  11. 2.2 11 km NNE of Dillon, Montana
  12. 2.5 13 km SSE of Harrison, Montana
  13. 1.5 11 km N of Ennis, Montana
  14. 1.5 15 km SSE of Pony, Montana
  15. 2.0 3 km WNW of Pony, 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.