QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8ml

Earthquake near Libby, MT

No earthquake was likely felt in Libby in the 24 hours to 1:23 pm MST (20:23 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 1.8 earthquake was recorded 28 km (17 mi) north-northwest of Libby, MT, at 8:31 pm MST on 31 January 2025 (03:31 UTC), 5.8 km deep.

USGS: 15 km SE of Sylvanite, Montana

8:31 pm MST, Jan 31, 2025 · · 5.8 km deep · released about 14 lb of TNT

10 km30 km60 km120 km N Lincoln County 21 kmBoundary County 61 kmBonner County 73 kmSanders County 104 kmPend Oreille County 111 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
8:31 pm MST on 31 January 2025 ()
Where
28 km (17 mi) north-northwest of Libby, MT · earthquakes near Libby
Montana today
every earthquake in Montana in the last 24 hours
Magnitude
M 1.8 (ml)
Depth
5.8 km below the surface
Felt
no reports yet
Nearest
Lincoln County, 21 km ESE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 648 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 Libby, 28 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 14 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,100,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 760,000× the energy of this one
  3. Around the size people start to feel M 3.0 68× the energy of this one
  4. This earthquake M 1.8 about 14 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 48.6117, -115.7335. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Lincoln County, MT 21 km (13 mi) ESE earthquakes near Lincoln County
Boundary County, ID 61 km (38 mi) WNW earthquakes near Boundary County
Bonner County, ID 73 km (46 mi) WSW earthquakes near Bonner County
Sanders County, MT 104 km (64 mi) SSE earthquakes near Sanders County
Pend Oreille County, WA 111 km (69 mi) W earthquakes near Pend Oreille County
Kootenai County, ID 126 km (78 mi) SW earthquakes near Kootenai 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. 1.9 19 km NE of Troy, 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.