QuakeIndex

Earthquake · reviewed by a seismologist

M 1.6ml

Earthquake near Belgrade, MT

No earthquake was likely felt in Belgrade in the 24 hours to 8:33 am MST (15:33 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 1.6 earthquake was recorded 38 km (24 mi) north-northwest of Belgrade, MT, at 8:08 am MST on 6 December 2021 (15:08 UTC), 11 km deep.

USGS: 6 km NW of Ponderosa Pines, Montana

52 km (32 mi) NW of Bozeman, MT

8:08 am MST, Dec 6, 2021 · · 11 km deep · released about 6.4 lb of TNT

Every earthquake near Belgrade Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Broadwater County 30 kmJefferson County 48 kmGallatin County 65 kmMeagher County 70 kmMadison County 90 kmSilver Bow County 96 kmPark County 97 kmSweet Grass County 119 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
8:08 am MST on 6 December 2021 ()
Where
38 km (24 mi) north-northwest of Belgrade, MT · earthquakes near Belgrade
Montana today
every earthquake in Montana in the last 24 hours
Magnitude
M 1.6 (ml)
Depth
11 km below the surface
Felt
no reports yet
Nearest
Broadwater County, 30 km N
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1801 days ago

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

At this magnitude and depth it was probably too small to be felt, even directly above it. In Belgrade, 38 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.

Earthquakes near other towns within 30 km: Three Forks, Manhattan, Townsend.

How big was it?

This earthquake released about 6.4 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.5 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 2,400,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,700,000× the energy of this one
  3. Around the size people start to feel M 3.0 150× the energy of this one
  4. This earthquake M 1.6 about 6.4 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 9,400 times the energy of this one.

Before 2016, the USGS record lists 6 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.6 The 1925 Clarkston Valley, Montana Earthquake · 6 km WNW of this epicentre
  2. 6.4 Clarkston Valley, Montana (Aftershock) · 6 km WNW of this epicentre
  3. 5.5 Clarkston Valley, Montana (Aftershock) · 6 km WNW of this epicentre
  4. 5.5 Clarkston Valley, Montana (Aftershock) · 6 km WNW of this epicentre
  5. 5.5 Clarkston Valley, Montana (Aftershock) · 6 km WNW 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 46.0668, -111.4380. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Broadwater County, MT 30 km (18 mi) N earthquakes near Broadwater County
Jefferson County, MT 48 km (30 mi) W earthquakes near Jefferson County
Gallatin County, MT 65 km (40 mi) SSE earthquakes near Gallatin County
Meagher County, MT 70 km (43 mi) NE earthquakes near Meagher County
Madison County, MT 90 km (56 mi) SSW earthquakes near Madison County
Silver Bow County, MT 96 km (60 mi) W earthquakes near Silver Bow County

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

Aftershocks so far

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

  1. 1.7 0 km SW of Three Forks, Montana
  2. 1.8 7 km W of Townsend, Montana
  3. 1.6 7 km W of Townsend, Montana
  4. 1.9 9 km W of Townsend, Montana
  5. 1.6 5 km SSW of Willow Creek, Montana
  6. 1.8 5 km NNW of Logan, Montana
  7. 1.6 Western Montana
  8. 1.6 3 km WSW of Ponderosa Pines, Montana
  9. 1.6 8 km W of Townsend, Montana
  10. 1.7 6 km WSW of Townsend, Montana
  11. 1.6 14 km ESE of Harrison, Montana
  12. 1.5 10 km WNW of Four Corners, Montana
  13. 1.6 5 km SE of Three Forks, Montana
  14. 1.6 5 km WSW of Logan, Montana
  15. 2.0 4 km NNW of Logan, 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.