QuakeIndex

Earthquake · reviewed by a seismologist

M 2.1ml

Earthquake near Belgrade, MT

No earthquake was likely felt in Belgrade in the 24 hours to 10:35 am MST (17:35 UTC). The last one was M 1.6, 8 km (5 mi) WSW, at 4:23 pm MDT on 28 September 2025, estimated intensity II (weak) in town. Every earthquake near Belgrade

This page: a magnitude 2.1 earthquake was recorded 50 km (31 mi) southwest of Belgrade, MT, at 1:54 pm MDT on 5 September 2023 (19:54 UTC), less than 1 km deep.

USGS: 17 km NNE of Ennis, Montana

53 km (33 mi) WSW of Bozeman, MT

1:54 pm MDT, Sep 5, 2023 · · 0.0 km deep · released about 43 lb of TNT

10 km30 km60 km120 km N Madison County 27 kmGallatin County 40 kmJefferson County 76 kmSilver Bow County 88 kmPark County 89 kmBroadwater County 93 kmBeaverhead County 103 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
1:54 pm MDT on 5 September 2023 ()
Where
50 km (31 mi) southwest of Belgrade, MT · earthquakes near Belgrade
Montana today
every earthquake in Montana in the last 24 hours
Magnitude
M 2.1 (ml)
Depth
0.0 km below the surface
Felt
no reports yet
Nearest
Madison County, 27 km SW
Nearest mapped fault
Madison fault, 8 km from its surface trace — near is not the same as on
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1028 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 17 km (11 mi) from the epicentre. In Belgrade, 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.

How big was it?

This earthquake released about 43 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.1 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 350,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 250,000× the energy of this one
  3. Around the size people start to feel M 3.0 22× the energy of this one
  4. This earthquake M 2.1 about 43 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 4.2 on 2019-08-16 — about 1,400 times the energy of this one.

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 45.4990, -111.6792. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Madison County, MT 27 km (17 mi) SW earthquakes near Madison County
Gallatin County, MT 40 km (25 mi) E earthquakes near Gallatin County
Jefferson County, MT 76 km (47 mi) NNW earthquakes near Jefferson County
Silver Bow County, MT 88 km (55 mi) WNW earthquakes near Silver Bow County
Park County, MT 89 km (55 mi) E earthquakes near Park County
Broadwater County, MT 93 km (58 mi) N earthquakes near Broadwater 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. 2.1 13 km SSE of Pony, Montana
  2. 1.9 21 km S of Ennis, Montana
  3. 1.6 28 km SE of Virginia City, Montana
  4. 1.8 6 km NE of Three Forks, Montana
  5. 2.0 11 km S of Ennis, Montana
  6. 1.5 28 km S of Ennis, Montana
  7. 2.3 3 km NNW of Pony, Montana
  8. 2.0 2 km NNW of Pony, Montana
  9. 1.6 29 km SSE of Virginia City, Montana
  10. 2.4 8 km SSE of Pony, Montana
  11. 1.5 28 km SE of Virginia City, Montana
  12. 1.5 28 km S of Ennis, Montana
  13. 2.0 4 km ESE of Three Forks, Montana
  14. 2.4 7 km NW of Willow Creek, Montana
  15. 2.0 7 km SE 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.