QuakeIndex

Earthquake · reviewed by a seismologist

M 1.9ml

Earthquake near Great Falls, MT

No earthquake was likely felt in Great Falls in the 24 hours to 2:18 am MST (09:18 UTC). The last one was M 3.7, 9 km (6 mi) NNW, at 7:40 am MDT on 18 September 2026, estimated intensity III (weak) in town; 176 felt reports to USGS. Every earthquake near Great Falls

This page: a magnitude 1.9 earthquake was recorded 12 km (8 mi) north-northeast of Great Falls, MT, at 10:45 pm MDT on 15 April 2026 (04:45 UTC), 2.6 km deep.

USGS: 9 km N of Black Eagle, Montana

12 km (8 mi) NNE of Great Falls, MT

10:45 pm MDT, Apr 15, 2026 · · 2.6 km deep · released about 24 lb of TNT

10 km30 km60 km120 km N Cascade County 33 kmChouteau County 69 kmTeton County 80 kmJudith Basin County 96 kmPondera County 99 kmLewis and Clark County 100 kmLiberty County 107 kmMeagher County 117 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
10:45 pm MDT on 15 April 2026 ()
Where
12 km (8 mi) north-northeast of Great Falls, MT · earthquakes near Great Falls
Montana today
every earthquake in Montana in the last 24 hours
Magnitude
M 1.9 (ml)
Depth
2.6 km below the surface
Felt
no reports yet
Nearest
Cascade County, 33 km SSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 208 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 15 km (9 mi) from the epicentre. In Great Falls, 12 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: Great Falls 12 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 24 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.9 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 640,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 450,000× the energy of this one
  3. Around the size people start to feel M 3.0 40× the energy of this one
  4. This earthquake M 1.9 about 24 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 2026-01-29 — about 2,500 times the energy of this one.

Before 2016, the USGS record since 1900 lists no earthquake of M5 or more within 50 km.

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 47.6085, -111.2610. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Cascade County, MT 33 km (21 mi) SSW earthquakes near Cascade County
Chouteau County, MT 69 km (43 mi) ENE earthquakes near Chouteau County
Teton County, MT 80 km (50 mi) WNW earthquakes near Teton County
Judith Basin County, MT 96 km (60 mi) SE earthquakes near Judith Basin County
Pondera County, MT 99 km (62 mi) NW earthquakes near Pondera County
Lewis and Clark County, MT 100 km (62 mi) WSW earthquakes near Lewis and Clark County

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

Aftershocks so far

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

  1. 3.7 7 km NNW of Black Eagle, Montana
  2. 2.4 9 km NNE of Black Eagle, 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.