QuakeIndex

Earthquake · reviewed by a seismologist

M 1.5ml

Earthquake near Four Corners, MT

No earthquake was likely felt in Four Corners in the 24 hours to 6:59 pm MST (01:59 UTC). The last one was M 3.0, 15 km (9 mi) N, at 7:42 am MDT on 1 June 2024, estimated intensity II (weak) in town; 20 felt reports to USGS. Every earthquake near Four Corners

This page: a magnitude 1.5 earthquake was recorded 10 km (6 mi) west of Four Corners, MT, at 7:44 am MDT on 29 August 2023 (13:44 UTC), 13 km deep.

USGS: 10 km WNW of Four Corners, Montana

20 km (13 mi) W of Bozeman, MT

7:44 am MDT, Aug 29, 2023 · · 13 km deep · released about 5.9 lb of TNT

Every earthquake near Four Corners Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Gallatin County 19 kmMadison County 59 kmPark County 64 kmBroadwater County 76 kmJefferson County 78 kmMeagher County 108 kmSweet Grass County 108 kmSilver Bow County 108 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
7:44 am MDT on 29 August 2023 ()
Where
10 km (6 mi) west of Four Corners, MT · earthquakes near Four Corners
Montana today
every earthquake in Montana in the last 24 hours
Magnitude
M 1.5 (ml)
Depth
13 km below the surface
Felt
no reports yet
Nearest
Gallatin County, 19 km SE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1167 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth it was probably too small to be felt, even directly above it. In Four Corners, 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.

Earthquakes near other towns within 30 km: Belgrade, Bozeman, Manhattan.

How big was it?

This earthquake released about 5.9 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.5 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 2,500,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,800,000× the energy of this one
  3. Around the size people start to feel M 3.0 160× the energy of this one
  4. This earthquake M 1.5 about 5.9 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 10,000 times the energy of this one.

Before 2016, the USGS record lists 5 earthquakes of M5 or more within 50 km:

  1. 6.6 The 1925 Clarkston Valley, Montana Earthquake · 49 km NNW of this epicentre
  2. 6.4 Clarkston Valley, Montana (Aftershock) · 49 km NNW of this epicentre
  3. 5.5 Clarkston Valley, Montana (Aftershock) · 49 km NNW of this epicentre
  4. 5.5 Clarkston Valley, Montana (Aftershock) · 49 km NNW of this epicentre
  5. 5.5 Clarkston Valley, Montana (Aftershock) · 49 km NNW 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 45.6563, -111.3143. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Gallatin County, MT 19 km (12 mi) SE earthquakes near Gallatin County
Madison County, MT 59 km (37 mi) SW earthquakes near Madison County
Park County, MT 64 km (40 mi) ESE earthquakes near Park County
Broadwater County, MT 76 km (47 mi) N earthquakes near Broadwater County
Jefferson County, MT 78 km (48 mi) NW earthquakes near Jefferson County
Meagher County, MT 108 km (67 mi) NNE earthquakes near Meagher County

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

Aftershocks so far

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

  1. 1.6 6 km NW of Logan, Montana
  2. 1.5 4 km NE of Three Forks, Montana
  3. 2.0 14 km ESE of Harrison, Montana
  4. 1.7 4 km SW of Churchill, Montana
  5. 1.9 9 km SSE of Harrison, Montana
  6. 1.8 15 km ESE of Harrison, Montana
  7. 2.4 16 km ESE of Harrison, Montana
  8. 2.5 16 km ESE of Harrison, Montana
  9. 2.4 17 km ESE of Harrison, Montana
  10. 1.6 6 km NE of Three Forks, Montana
  11. 1.6 2 km E of Churchill, Montana
  12. 2.1 6 km NE of Logan, Montana
  13. 2.1 13 km SSE of Pony, Montana
  14. 1.7 13 km S of Bozeman, Montana
  15. 1.8 6 km NE of Three Forks, 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.