QuakeIndex

Earthquake · reviewed by a seismologist

M 1.6ml

Earthquake near Dillon, MT

No earthquake was likely felt in Dillon in the 24 hours to 9:48 am MST (16:48 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 1.6 earthquake was recorded 30 km (19 mi) southeast of Dillon, MT, at 11:31 pm MDT on 28 October 2019 (05:31 UTC), 5.0 km deep.

USGS: 30 km SE of Dillon, Montana

11:31 pm MDT, Oct 28, 2019 · · 5.0 km deep · released about 7.6 lb of TNT

Every earthquake near Dillon Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Beaverhead County 43 kmMadison County 48 kmClark County 82 kmSilver Bow County 100 kmGallatin County 109 kmFremont County 113 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
11:31 pm MDT on 28 October 2019 ()
Where
30 km (19 mi) southeast of Dillon, MT · earthquakes near Dillon
Montana today
every earthquake in Montana in the last 24 hours
Magnitude
M 1.6 (ml)
Depth
5.0 km below the surface
Felt
no reports yet
Nearest
Beaverhead County, 43 km WNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2570 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 10 km (6 mi) from the epicentre. In Dillon, 30 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 7.6 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.6 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 2,000,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,400,000× the energy of this one
  3. Around the size people start to feel M 3.0 130× the energy of this one
  4. This earthquake M 1.6 about 7.6 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 4.6 on 2019-04-09 — about 32,000 times the energy of this one.

Before 2016, the USGS record lists 3 earthquakes of M5 or more within 50 km:

  1. 5.6 16 km N of Dillon, Montana · 43 km NNW of this epicentre
  2. 5.1 19 km NW of Lima, Montana · 41 km SW of this epicentre
  3. 5.1 22 km NW of Lima, Montana · 43 km SW 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 45.0250, -112.3612. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Beaverhead County, MT 43 km (27 mi) WNW earthquakes near Beaverhead County
Madison County, MT 48 km (30 mi) NE earthquakes near Madison County
Clark County, ID 82 km (51 mi) S earthquakes near Clark County
Silver Bow County, MT 100 km (62 mi) NNW earthquakes near Silver Bow County
Gallatin County, MT 109 km (67 mi) ENE earthquakes near Gallatin County
Fremont County, ID 113 km (70 mi) SE earthquakes near Fremont County

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

Aftershocks so far

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

  1. 1.7 17 km ESE of Dillon, Montana
  2. 1.8 7 km W of Sheridan, Montana
  3. 1.6 3 km ENE of Lima, Montana
  4. 1.5 18 km ESE of Dillon, Montana
  5. 2.7 23 km ESE of Dillon, Montana
  6. 1.6 23 km ESE of Dillon, Montana
  7. 2.6 16 km NE of Lima, Montana
  8. 1.8 46 km NNE of Spencer, Idaho
  9. 1.7 17 km ESE of Dillon, Montana
  10. 1.7 6 km E of Lima, Montana
  11. 1.6 24 km SSW of Virginia City, Montana
  12. 2.0 28 km SW of Dillon, Montana
  13. 1.6 16 km ESE of Dillon, Montana
  14. 1.7 8 km E of Lima, Montana
  15. 1.6 7 km E 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.