QuakeIndex

Earthquake · reviewed by a seismologist

M 1.6ml

Earthquake near West Yellowstone, MT

No earthquake was likely felt in West Yellowstone in the 24 hours to 7:44 am MST (14:44 UTC). The last one was M 2.8, 11 km (7 mi) NNW, at 1:21 am MDT on 8 September 2026, estimated intensity II (weak) in town. Every earthquake near West Yellowstone

This page: a magnitude 1.6 earthquake was recorded 9 km (6 mi) north-northwest of West Yellowstone, MT, at 8:56 pm MDT on 20 August 2020 (02:56 UTC), 12 km deep.

USGS: Idaho-Montana border region

8:56 pm MDT, Aug 20, 2020 · · 12 km deep · released about 9 lb of TNT

Every earthquake near West Yellowstone Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Fremont County 65 kmGallatin County 86 kmMadison County 90 kmPark County 93 kmTeton County 95 kmTeton County 109 kmClark County 109 kmMadison 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
8:56 pm MDT on 20 August 2020 ()
Where
9 km (6 mi) north-northwest of West Yellowstone, MT · earthquakes near West Yellowstone
Magnitude
M 1.6 (ml)
Depth
12 km below the surface
Felt
no reports yet
Nearest
Fremont County, 65 km SSW
Nearest mapped fault
Red Canyon fault, 4 km from its surface trace — near is not the same as on
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2273 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 West Yellowstone, 9 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 9 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.6 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,700,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,200,000× the energy of this one
  3. Around the size people start to feel M 3.0 110× the energy of this one
  4. This earthquake M 1.6 about 9 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 in our catalogue was M 4.4 on 2017-06-16 — about 12,000 times the energy of this one.

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 44.7408, -111.1285. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Fremont County, ID 65 km (40 mi) SSW earthquakes near Fremont County
Gallatin County, MT 86 km (54 mi) N earthquakes near Gallatin County
Madison County, MT 90 km (56 mi) NW earthquakes near Madison County
Park County, MT 93 km (58 mi) NNE earthquakes near Park County
Teton County, WY 95 km (59 mi) SE earthquakes near Teton County
Teton County, ID 109 km (68 mi) S earthquakes near Teton County

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

Aftershocks so far

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

  1. 1.6 13 km SE of West Yellowstone, Montana
  2. 1.6 23 km WNW of Hebgen Lake Estates, Montana
  3. 2.0 22 km WNW of Hebgen Lake Estates, Montana
  4. 1.6 26 km SSE of West Yellowstone, Montana
  5. 2.2 1 km SSW of West Yellowstone, Montana
  6. 2.1 1 km SSW of West Yellowstone, Montana
  7. 2.3 1 km SW of West Yellowstone, Montana
  8. 1.5 29 km E of West Yellowstone, Montana
  9. 2.0 31 km E of West Yellowstone, Montana
  10. 1.8 30 km E of West Yellowstone, Montana
  11. 1.7 31 km E of West Yellowstone, Montana
  12. 1.5 8 km ENE of Hebgen Lake Estates, Montana
  13. 1.6 8 km E of Hebgen Lake Estates, Montana
  14. 1.9 22 km WNW of Hebgen Lake Estates, Montana
  15. 1.7 7 km E of Hebgen Lake Estates, 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.