QuakeIndex

Earthquake · reviewed by a seismologist

M 3.5ml

Earthquake near Three Forks, MT

No earthquake was likely felt in Three Forks in the 24 hours to 8:30 am MST (15:30 UTC). The last one was M 1.6, 7 km (5 mi) NE, at 4:03 pm MDT on 11 August 2026, estimated intensity II (weak) in town. Every earthquake near Three Forks

This page: a magnitude 3.5 earthquake was recorded 13 km (8 mi) west-southwest of Three Forks, MT, at 9:59 pm MST on 11 January 2017 (04:59 UTC), 18 km deep. 16 people have reported feeling it to USGS.

USGS: 5 km WNW of Willow Creek, Montana

53 km (33 mi) WNW of Bozeman, MT

9:59 pm MST, Jan 11, 2017 · · 18 km deep · released about 2.6 tons of TNT

Every earthquake near Three Forks Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Jefferson County 42 kmGallatin County 55 kmBroadwater County 57 kmMadison County 60 kmSilver Bow County 74 kmPark County 100 kmMeagher County 102 kmDeer Lodge County 115 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
9:59 pm MST on 11 January 2017 ()
Where
13 km (8 mi) west-southwest of Three Forks, MT · earthquakes near Three Forks
Montana today
every earthquake in Montana in the last 24 hours
Magnitude
M 3.5 (ml)
Depth
18 km below the surface
Felt
16 reports · strongest reported intensity IV
Measured shaking
intensity III (ShakeMap)
Nearest
Jefferson County, 42 km NW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2008 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 60 km (37 mi) from the epicentre. In Three Forks, 13 km away, the estimate is intensity III (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: Three Forks 13 km, intensity III · Manhattan 29 km, intensity II · Whitehall 31 km, intensity II · Belgrade 42 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 2.6 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.5 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 65,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 2,900× the energy of this one
  3. Magna, Utah 2020 M 5.7 2,100× the energy of this one
  4. This earthquake M 3.5 about 2.6 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 5.4× 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

The largest earthquake within 50 km since 2016 was M 4.0 on 2016-09-03 — about 6.5 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 · 30 km NNE of this epicentre
  2. 6.4 Clarkston Valley, Montana (Aftershock) · 30 km NNE of this epicentre
  3. 5.5 Clarkston Valley, Montana (Aftershock) · 30 km NNE of this epicentre
  4. 5.5 Clarkston Valley, Montana (Aftershock) · 30 km NNE of this epicentre
  5. 5.5 Clarkston Valley, Montana (Aftershock) · 30 km NNE 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 45.8420, -111.7045. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Jefferson County, MT 42 km (26 mi) NW earthquakes near Jefferson County
Gallatin County, MT 55 km (34 mi) SE earthquakes near Gallatin County
Broadwater County, MT 57 km (35 mi) NNE earthquakes near Broadwater County
Madison County, MT 60 km (37 mi) SSW earthquakes near Madison County
Silver Bow County, MT 74 km (46 mi) W earthquakes near Silver Bow County
Park County, MT 100 km (62 mi) ESE earthquakes near Park County

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

Aftershocks so far

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

  1. 2.3 7 km W of Willow Creek, Montana
  2. 2.4 6 km W of Willow Creek, Montana
  3. 1.6 13 km WNW of Whitehall, Montana
  4. 1.9 6 km NE of Logan, Montana
  5. 2.2 17 km S of Whitehall, Montana
  6. 1.6 17 km S of Whitehall, Montana
  7. 1.8 4 km W of Ponderosa Pines, Montana
  8. 1.9 17 km S of Whitehall, Montana
  9. 2.4 16 km WNW of Pony, Montana
  10. 1.8 17 km S of Whitehall, Montana
  11. 2.9 15 km S of Whitehall, Montana
  12. 3.3 17 km S of Whitehall, Montana
  13. 2.6 15 km SSE of Elkhorn, Montana
  14. 1.8 17 km S of Whitehall, Montana
  15. 3.3 17 km SSW of Whitehall, 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.