QuakeIndex

Earthquake · reviewed by a seismologist

M 2.3ml

Earthquake near Townsend, MT

No earthquake was likely felt in Townsend in the 24 hours to 7:14 am MST (14:14 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 2.3 earthquake was recorded 19 km (12 mi) south-southwest of Townsend, MT, at 4:43 am MST on 28 December 2019 (11:43 UTC), 9.9 km deep.

USGS: 2 km SW of Radersburg, Montana

4:43 am MST, Dec 28, 2019 · · 9.9 km deep · released about 94 lb of TNT

Every earthquake near Townsend Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Broadwater County 21 kmJefferson County 32 kmMeagher County 72 kmGallatin County 83 kmSilver Bow County 84 kmMadison County 97 kmDeer Lodge County 115 kmPark County 118 kmLewis and Clark 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
4:43 am MST on 28 December 2019 ()
Where
19 km (12 mi) south-southwest of Townsend, MT · earthquakes near Townsend
Montana today
every earthquake in Montana in the last 24 hours
Magnitude
M 2.3 (ml)
Depth
9.9 km below the surface
Felt
no reports yet
Nearest
Broadwater County, 21 km NE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2510 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 18 km (11 mi) from the epicentre. In Townsend, 19 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 94 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.3 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 160,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 110,000× the energy of this one
  3. Around the size people start to feel M 3.0 10× the energy of this one
  4. This earthquake M 2.3 about 94 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 4.2 on 2019-08-16 — about 640 times the energy of this one.

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 · 16 km SE of this epicentre
  2. 6.4 Clarkston Valley, Montana (Aftershock) · 16 km SE of this epicentre
  3. 6.1 The 1935 Helena, Montana Earthquakes (Mainshock) · 46 km N of this epicentre
  4. 5.9 The 1935 Helena, Montana Earthquakes (Largest Aftershock) · 43 km NNW of this epicentre
  5. 5.5 Clarkston Valley, Montana (Aftershock) · 16 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 46.1783, -111.6533. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Broadwater County, MT 21 km (13 mi) NE earthquakes near Broadwater County
Jefferson County, MT 32 km (20 mi) W earthquakes near Jefferson County
Meagher County, MT 72 km (45 mi) NE earthquakes near Meagher County
Gallatin County, MT 83 km (51 mi) SSE earthquakes near Gallatin County
Silver Bow County, MT 84 km (52 mi) WSW earthquakes near Silver Bow County
Madison County, MT 97 km (60 mi) SSW earthquakes near Madison County

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

Aftershocks so far

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

  1. 1.6 4 km NNW of Logan, Montana
  2. 1.8 Western Montana
  3. 2.4 2 km SW of Ponderosa Pines, Montana
  4. 2.0 11 km SSW of Radersburg, Montana
  5. 1.6 2 km ENE of Manhattan, Montana
  6. 1.6 6 km WSW of Townsend, Montana
  7. 2.0 3 km WNW of Manhattan, Montana
  8. 2.3 2 km W of Manhattan, Montana
  9. 1.7 8 km S of Ponderosa Pines, Montana
  10. 1.7 1 km SE of South Hills, Montana
  11. 1.6 6 km W of Townsend, Montana
  12. 1.8 4 km S of Radersburg, Montana
  13. 2.5 7 km WNW of Willow Creek, Montana
  14. 2.1 6 km ENE of Toston, Montana
  15. 1.7 5 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.