QuakeIndex

Earthquake · reviewed by a seismologist

M 2.4ml

Earthquake near Libby, MT

No earthquake was likely felt in Libby in the 24 hours to 3:33 pm MST (22:33 UTC). The last one was M 3.1, 31 km (19 mi) WSW, at 2:24 pm MST on 21 November 2025, estimated intensity II (weak) in town. Every earthquake near Libby

This page: a magnitude 2.4 earthquake was recorded 37 km (23 mi) south of Libby, MT, at 7:25 pm MDT on 2 August 2024 (01:25 UTC), 5.1 km deep.

USGS: 23 km ENE of Noxon, Montana

7:25 pm MDT, Aug 2, 2024 · · 5.1 km deep · released about 140 lb of TNT

10 km30 km60 km120 km N Sanders County 40 kmLincoln County 55 kmShoshone County 84 kmBonner County 90 kmKootenai County 100 kmMineral County 107 kmFlathead County 109 kmBoundary County 111 kmLake County 114 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
7:25 pm MDT on 2 August 2024 ()
Where
37 km (23 mi) south of Libby, MT · earthquakes near Libby
Montana today
every earthquake in Montana in the last 24 hours
Magnitude
M 2.4 (ml)
Depth
5.1 km below the surface
Felt
no reports yet
Nearest
Sanders County, 40 km SE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 830 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 21 km (13 mi) from the epicentre. In Libby, 37 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 140 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.4 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 110,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 78,000× the energy of this one
  3. Around the size people start to feel M 3.0 6.9× the energy of this one
  4. This earthquake M 2.4 about 140 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 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 48.0548, -115.4822. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Sanders County, MT 40 km (25 mi) SE earthquakes near Sanders County
Lincoln County, MT 55 km (34 mi) N earthquakes near Lincoln County
Shoshone County, ID 84 km (52 mi) SSW earthquakes near Shoshone County
Bonner County, ID 90 km (56 mi) WNW earthquakes near Bonner County
Kootenai County, ID 100 km (62 mi) WSW earthquakes near Kootenai County
Mineral County, MT 107 km (67 mi) SSE earthquakes near Mineral 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. 3.1 20 km N of Heron, Montana
  2. 1.7 21 km SSE of Happys Inn, 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.