QuakeIndex

Earthquake · reviewed by a seismologist

M 1.7ml

Earthquake near Townsend, MT

No earthquake was likely felt in Townsend in the 24 hours to 10:07 pm MST (05:07 UTC). The last one was M 1.7, 9 km (5 mi) W, at 2:32 pm MDT on 15 October 2026, estimated intensity II (weak) in town. Every earthquake near Townsend

This page: a magnitude 1.7 earthquake was recorded 10 km (6 mi) east-northeast of Townsend, MT, at 2:57 am MST on 25 December 2018 (09:57 UTC), less than 1 km deep.

USGS: 10 km ENE of Townsend, Montana

2:57 am MST, Dec 25, 2018 · · -2.6 km deep · released about 9.3 lb of TNT

Every earthquake near Townsend Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Broadwater County 8 kmMeagher County 44 kmJefferson County 57 kmGallatin County 95 kmCascade County 107 kmSilver Bow County 110 kmJudith Basin County 112 kmLewis and Clark County 113 kmWheatland 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
2:57 am MST on 25 December 2018 ()
Where
10 km (6 mi) east-northeast of Townsend, MT · earthquakes near Townsend
Montana today
every earthquake in Montana in the last 24 hours
Magnitude
M 1.7 (ml)
Depth
-2.6 km below the surface
Felt
no reports yet
Nearest
Broadwater County, 8 km WSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2880 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 12 km (7 mi) from the epicentre. In Townsend, 10 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: Townsend 10 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 9.3 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 1,600,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,100,000× the energy of this one
  3. Around the size people start to feel M 3.0 100× the energy of this one
  4. This earthquake M 1.7 about 9.3 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 8 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.6 The 1925 Clarkston Valley, Montana Earthquake · 32 km SSW of this epicentre
  2. 6.4 Clarkston Valley, Montana (Aftershock) · 32 km SSW of this epicentre
  3. 6.1 The 1935 Helena, Montana Earthquakes (Mainshock) · 32 km NW of this epicentre
  4. 5.9 The 1935 Helena, Montana Earthquakes (Largest Aftershock) · 40 km WNW of this epicentre
  5. 5.5 Clarkston Valley, Montana (Aftershock) · 32 km SSW 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 46.3587, -111.3985. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Broadwater County, MT 8 km (5 mi) WSW earthquakes near Broadwater County
Meagher County, MT 44 km (28 mi) NE earthquakes near Meagher County
Jefferson County, MT 57 km (35 mi) WSW earthquakes near Jefferson County
Gallatin County, MT 95 km (59 mi) S earthquakes near Gallatin County
Cascade County, MT 107 km (66 mi) N earthquakes near Cascade County
Silver Bow County, MT 110 km (68 mi) WSW earthquakes near Silver Bow 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. 1.6 7 km NNW of Logan, Montana
  2. 1.6 6 km WSW of Townsend, Montana
  3. 1.6 6 km W of Townsend, Montana
  4. 1.5 4 km SW of The Silos, Montana
  5. 1.9 14 km SW of Radersburg, Montana
  6. 1.6 6 km W of Townsend, Montana
  7. 1.6 7 km WSW of Townsend, Montana
  8. 1.9 30 km NE of Winston, Montana
  9. 1.6 5 km NNW of Logan, Montana
  10. 1.5 7 km W of Townsend, Montana
  11. 1.5 7 km SSW of The Silos, Montana
  12. 1.9 6 km SSW of The Silos, Montana
  13. 1.6 7 km NE of Three Forks, Montana
  14. 2.5 10 km NNE of Toston, Montana
  15. 1.7 7 km W of Townsend, 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.