QuakeIndex

Earthquake · reviewed by a seismologist

M 1.9ml

Earthquake near Seeley Lake, MT

No earthquake was likely felt in Seeley Lake in the 24 hours to 3:39 pm MST (22:39 UTC). The last one was M 3.1, 26 km (16 mi) ESE, at 8:34 pm MDT on 4 October 2026, estimated intensity II (weak) in town; 4 felt reports to USGS. Every earthquake near Seeley Lake

This page: a magnitude 1.9 earthquake was recorded 32 km (20 mi) northeast of Seeley Lake, MT, at 11:31 pm MDT on 7 September 2018 (05:31 UTC), 21 km deep.

USGS: 32 km NE of Seeley Lake, Montana

11:31 pm MDT, Sep 7, 2018 · · 21 km deep · released about 21 lb of TNT

10 km30 km60 km120 km N Powell County 58 kmLewis and Clark County 62 kmMissoula County 67 kmLake County 79 kmTeton County 83 kmGranite County 108 kmPondera County 120 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
11:31 pm MDT on 7 September 2018 ()
Where
32 km (20 mi) northeast of Seeley Lake, MT · earthquakes near Seeley Lake
Montana today
every earthquake in Montana in the last 24 hours
Magnitude
M 1.9 (ml)
Depth
21 km below the surface
Felt
no reports yet
Nearest
Powell County, 58 km SSE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2986 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 Seeley Lake, 32 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 21 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 5.8 710,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 500,000× the energy of this one
  3. Around the size people start to feel M 3.0 45× the energy of this one
  4. This earthquake M 1.9 about 21 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 47.3462, -113.1355. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Powell County, MT 58 km (36 mi) SSE earthquakes near Powell County
Lewis and Clark County, MT 62 km (39 mi) ESE earthquakes near Lewis and Clark County
Missoula County, MT 67 km (42 mi) WSW earthquakes near Missoula County
Lake County, MT 79 km (49 mi) WNW earthquakes near Lake County
Teton County, MT 83 km (51 mi) NE earthquakes near Teton County
Granite County, MT 108 km (67 mi) SSW earthquakes near Granite County

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

Aftershocks so far

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

  1. 1.8 11 km W of Lincoln, Montana
  2. 2.3 13 km WNW of Lincoln, Montana
  3. 2.5 18 km N of Ovando, Montana
  4. 2.1 18 km WNW of Lincoln, Montana
  5. 2.5 8 km NW of Lincoln, Montana
  6. 2.7 19 km ENE of Seeley Lake, Montana
  7. 2.4 26 km ENE of Seeley Lake, Montana
  8. 2.5 19 km NW of Lincoln, Montana
  9. 2.3 16 km E of Ovando, Montana
  10. 2.2 26 km ESE of Condon, Montana
  11. 1.5 26 km ESE of Condon, Montana
  12. 2.8 35 km WSW of Augusta, Montana
  13. 2.5 39 km NNE of Ovando, Montana
  14. 3.3 40 km NE of Seeley Lake, Montana
  15. 2.7 20 km ENE of Seeley Lake, 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.