QuakeIndex

Earthquake · reviewed by a seismologist

M 2.2ml

Earthquake near West Yellowstone, MT

No earthquake was likely felt in West Yellowstone in the 24 hours to 8:26 am MST (15:26 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 2.2 earthquake was recorded 28 km (17 mi) east-northeast of West Yellowstone, MT, at 9:55 pm MDT on 29 August 2018 (03:55 UTC), 5.0 km deep.

USGS: 22 km SSW of Mammoth, Wyoming

9:55 pm MDT, Aug 29, 2018 · · 5.0 km deep · released about 52 lb of TNT

Every earthquake near West Yellowstone Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Park County 78 kmFremont County 83 kmTeton County 87 kmGallatin County 87 kmPark County 100 kmMadison County 107 kmTeton County 118 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
9:55 pm MDT on 29 August 2018 ()
Where
28 km (17 mi) east-northeast of West Yellowstone, MT · earthquakes near West Yellowstone
Magnitude
M 2.2 (ml)
Depth
5.0 km below the surface
Felt
no reports yet
Nearest
Park County, 78 km NNE
Nearest mapped fault
Red Canyon fault, 17 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 2995 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 17 km (11 mi) from the epicentre. In West Yellowstone, 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 52 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.2 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 290,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 200,000× the energy of this one
  3. Around the size people start to feel M 3.0 18× the energy of this one
  4. This earthquake M 2.2 about 52 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 since 2016 was M 4.4 on 2017-06-16 — about 2,000 times the energy of this one.

Before 2016, the USGS record lists 12 earthquakes of M5 or more within 50 km; the five largest:

  1. 7.2 The 1959 Hebgen Lake, Montana Earthquake · 32 km W of this epicentre
  2. 6.5 14 km N of Madison Junction, Wyoming · 8 km WSW of this epicentre
  3. 6.3 22 km SW of Mammoth, Wyoming · 7 km WNW of this epicentre
  4. 6.0 21 km E of West Yellowstone, Montana · 15 km SSW of this epicentre
  5. 5.9 26 km SSE of Mammoth, Wyoming · 15 km ESE of this epicentre

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 44.7820, -110.7910. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Park County, MT 78 km (49 mi) NNE earthquakes near Park County
Fremont County, ID 83 km (52 mi) SW earthquakes near Fremont County
Teton County, WY 87 km (54 mi) SSE earthquakes near Teton County
Gallatin County, MT 87 km (54 mi) NNW earthquakes near Gallatin County
Park County, WY 100 km (62 mi) ESE earthquakes near Park County
Madison County, MT 107 km (66 mi) NW earthquakes near Madison County

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

Aftershocks so far

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

  1. 2.3 47 km SSE of Mammoth, Wyoming
  2. 1.9 48 km SSE of Mammoth, Wyoming
  3. 2.0 47 km SSE of Mammoth, Wyoming
  4. 2.0 48 km SSE of Mammoth, Wyoming
  5. 2.2 47 km SSE of Mammoth, Wyoming
  6. 1.6 47 km SSE of Mammoth, Wyoming
  7. 1.7 47 km SSE of Mammoth, Wyoming
  8. 1.7 48 km SSE of Mammoth, Wyoming
  9. 2.7 47 km SSE of Mammoth, Wyoming
  10. 1.8 47 km SSE of Mammoth, Wyoming
  11. 1.7 47 km SSE of Mammoth, Wyoming
  12. 1.7 47 km SSE of Mammoth, Wyoming
  13. 1.6 Wyoming
  14. 2.2 10 km NE of West Yellowstone, Montana
  15. 1.6 12 km NE of West Yellowstone, 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.