QuakeIndex

Earthquake · reviewed by a seismologist

M 1.7ml

Earthquake near Dillon, MT

No earthquake was likely felt in Dillon in the 24 hours to 4:45 pm MST (23:45 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 1.7 earthquake was recorded 29 km (18 mi) west-southwest of Dillon, MT, at 11:21 am MST on 13 November 2018 (18:21 UTC), 8.0 km deep.

USGS: 28 km WSW of Dillon, Montana

11:21 am MST, Nov 13, 2018 · · 8.0 km deep · released about 11 lb of TNT

10 km30 km60 km120 km N Beaverhead County 7 kmLemhi County 75 kmMadison County 86 kmSilver Bow County 92 kmClark County 101 kmDeer Lodge County 112 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
11:21 am MST on 13 November 2018 ()
Where
29 km (18 mi) west-southwest of Dillon, MT · earthquakes near Dillon
Montana today
every earthquake in Montana in the last 24 hours
Magnitude
M 1.7 (ml)
Depth
8.0 km below the surface
Felt
no reports yet
Nearest
Beaverhead County, 7 km NE
Nearest mapped fault
Red Rock fault, 20 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 2922 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, 29 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 11 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.7 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,300,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 930,000× the energy of this one
  3. Around the size people start to feel M 3.0 83× the energy of this one
  4. This earthquake M 1.7 about 11 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

No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.

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

  1. 5.6 16 km N of Dillon, Montana · 40 km NE of this epicentre
  2. 5.1 19 km NW of Lima, Montana · 40 km SSE of this epicentre
  3. 5.1 22 km NW of Lima, Montana · 37 km SSE 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 45.0938, -112.9590. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Beaverhead County, MT 7 km (4 mi) NE earthquakes near Beaverhead County
Lemhi County, ID 75 km (47 mi) WSW earthquakes near Lemhi County
Madison County, MT 86 km (53 mi) ENE earthquakes near Madison County
Silver Bow County, MT 92 km (57 mi) NNE earthquakes near Silver Bow County
Clark County, ID 101 km (63 mi) SSE earthquakes near Clark County
Deer Lodge County, MT 112 km (70 mi) N earthquakes near Deer Lodge County

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

Aftershocks so far

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

  1. 1.7 17 km ESE of Dillon, Montana
  2. 1.7 36 km SSE of Wisdom, Montana
  3. 2.0 28 km SW of Dillon, Montana
  4. 1.6 16 km ESE of Dillon, Montana
  5. 1.5 17 km ESE of Dillon, Montana
  6. 1.8 20 km NW of Lima, Montana
  7. 1.8 17 km NNE of Dillon, Montana
  8. 2.2 31 km WSW of Dillon, Montana
  9. 1.8 29 km ENE of Leadore, Idaho
  10. 2.4 38 km SE of Wisdom, Montana
  11. 1.7 17 km NNE of Dillon, Montana
  12. 2.3 17 km N of Dillon, Montana
  13. 1.6 15 km N of Leadore, Idaho
  14. 1.6 36 km WSW of Dillon, Montana
  15. 1.7 29 km SW of Dillon, 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.