QuakeIndex

Earthquake · reviewed by a seismologist

M 3.3ml

Earthquake near Dillon, MT

No earthquake was likely felt in Dillon in the 24 hours to 3:31 pm MST (22:31 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 3.3 earthquake was recorded 41 km (26 mi) southwest of Dillon, MT, at 1:15 pm MST on 22 January 2017 (20:15 UTC), 1.1 km deep. 4 people have reported feeling it to USGS.

USGS: 41 km SW of Dillon, Montana

1:15 pm MST, Jan 22, 2017 · · 1.1 km deep · released about 1.4 tons of TNT

10 km30 km60 km120 km N Beaverhead County 21 kmLemhi County 67 kmClark County 94 kmMadison County 96 kmSilver Bow County 106 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
1:15 pm MST on 22 January 2017 ()
Where
41 km (26 mi) southwest of Dillon, MT · earthquakes near Dillon
Montana today
every earthquake in Montana in the last 24 hours
Magnitude
M 3.3 (ml)
Depth
1.1 km below the surface
Felt
4 reports · strongest reported intensity IV
Nearest
Beaverhead County, 21 km NNE
Nearest mapped fault
Red Rock fault, 15 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 2009 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 52 km (32 mi) from the epicentre. In Dillon, 41 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 41 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 1.4 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.3 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 120,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 5,400× the energy of this one
  3. Magna, Utah 2020 M 5.7 3,800× the energy of this one
  4. This earthquake M 3.3 about 1.4 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 2.9× 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 lists 2 earthquakes of M5 or more within 50 km:

  1. 5.1 19 km NW of Lima, Montana · 32 km SE of this epicentre
  2. 5.1 22 km NW of Lima, Montana · 29 km SE 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 44.9768, -113.0393. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Beaverhead County, MT 21 km (13 mi) NNE earthquakes near Beaverhead County
Lemhi County, ID 67 km (42 mi) W earthquakes near Lemhi County
Clark County, ID 94 km (58 mi) SE earthquakes near Clark County
Madison County, MT 96 km (60 mi) ENE earthquakes near Madison County
Silver Bow County, MT 106 km (66 mi) NNE earthquakes near Silver Bow County
Custer County, ID 124 km (77 mi) SW earthquakes near Custer County

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

Aftershocks so far

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

  1. 2.2 26 km ENE of Leadore, Idaho
  2. 2.4 32 km ENE of Leadore, Idaho
  3. 1.6 32 km ENE of Leadore, Idaho
  4. 2.4 7 km WNW of Dillon, Montana
  5. 1.6 12 km SSE of Dillon, Montana
  6. 2.2 10 km SSE of Dillon, Montana
  7. 1.6 26 km ENE of Leadore, Idaho
  8. 1.7 29 km WSW of Dillon, Montana
  9. 1.7 28 km WSW of Dillon, Montana
  10. 2.0 28 km WSW of Dillon, Montana
  11. 2.3 33 km WNW of Lima, Montana
  12. 1.7 8 km SSW of Dillon, MT
  13. 1.8 19 km W of Lima, Montana
  14. 2.2 24 km NNE of Lima, Montana
  15. 1.6 30 km NNW of Lima, 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.