QuakeIndex

Earthquake · reviewed by a seismologist

M 1.7md

Earthquake near Seeley Lake, MT

No earthquake was likely felt in Seeley Lake in the 24 hours to 1:08 am MST (08:08 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 1.7 earthquake was recorded 35 km (22 mi) northeast of Seeley Lake, MT, at 8:34 pm MDT on 17 April 2018 (02:34 UTC), 21 km deep.

USGS: 34 km NE of Seeley Lake, Montana

8:34 pm MDT, Apr 17, 2018 · · 21 km deep · released about 9.3 lb of TNT

10 km30 km60 km120 km N Powell County 63 kmLewis and Clark County 65 kmMissoula County 69 kmLake County 76 kmTeton County 80 kmGranite County 113 kmPondera County 116 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
8:34 pm MDT on 17 April 2018 ()
Where
35 km (22 mi) northeast of Seeley Lake, MT · earthquakes near Seeley Lake
Montana today
every earthquake in Montana in the last 24 hours
Magnitude
M 1.7 (md)
Depth
21 km below the surface
Felt
no reports yet
Nearest
Powell County, 63 km SSE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3130 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, 35 km away, the estimate is intensity I (not felt). 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 9.3 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.7 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,600,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,100,000× the energy of this one
  3. Around the size people start to feel M 3.0 100× the energy of this one
  4. This earthquake M 1.7 about 9.3 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 47.3940, -113.1482. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Powell County, MT 63 km (39 mi) SSE earthquakes near Powell County
Lewis and Clark County, MT 65 km (41 mi) ESE earthquakes near Lewis and Clark County
Missoula County, MT 69 km (43 mi) SW earthquakes near Missoula County
Lake County, MT 76 km (47 mi) WNW earthquakes near Lake County
Teton County, MT 80 km (50 mi) NE earthquakes near Teton County
Granite County, MT 113 km (70 mi) S earthquakes near Granite County

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

Aftershocks so far

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

  1. 2.3 Western 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. 2.7 19 km ENE of Seeley Lake, Montana
  6. 2.4 26 km ENE of Seeley Lake, Montana
  7. 2.5 19 km NW of Lincoln, Montana
  8. 2.3 16 km E of Ovando, Montana
  9. 2.2 26 km ESE of Condon, Montana
  10. 1.5 26 km ESE of Condon, Montana
  11. 2.8 35 km WSW of Augusta, Montana
  12. 2.5 39 km NNE of Ovando, Montana
  13. 3.3 40 km NE of Seeley Lake, Montana
  14. 2.7 20 km ENE of Seeley Lake, Montana
  15. 1.8 29 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.