QuakeIndex

Earthquake · reviewed by a seismologist

M 1.6ml

31 km ESE of Mammoth, Wyoming

Yes. A magnitude 1.6 earthquake was recorded 31 km ESE of Mammoth, Wyoming, at 11:08 pm MDT on 23 August 2025 (05:08 UTC), 14 km deep.

· 14 km deep · released about 6.4 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Park County 70 kmPark County 71 kmTeton County 90 kmGallatin County 98 kmCarbon County 111 kmSweet Grass County 111 kmFremont County 115 kmStillwater County 117 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
Magnitude
M 1.6 (ml)
Depth
14 km below the surface
Felt
no reports yet
Nearest
Park County, 70 km NNW
Nearest mapped fault
Mirror Plateau faults, 2 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 443 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. 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 6.4 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.5 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 2,400,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,700,000× the energy of this one
  3. Around the size people start to feel M 3.0 150× the energy of this one
  4. This earthquake M 1.6 about 6.4 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 4.2 on 2022-05-11 — about 10,000 times the energy of this one.

Before 2016, the USGS record lists 11 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.5 14 km N of Madison Junction, Wyoming · 45 km WSW of this epicentre
  2. 6.3 22 km SW of Mammoth, Wyoming · 42 km W of this epicentre
  3. 6.0 21 km E of West Yellowstone, Montana · 46 km WSW of this epicentre
  4. 5.9 26 km SSE of Mammoth, Wyoming · 24 km WSW of this epicentre
  5. 5.7 13 km SSW of Mammoth, Wyoming · 33 km W 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 44.8515, -110.3370. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Park County, MT 70 km (43 mi) NNW earthquakes near Park County
Park County, WY 71 km (44 mi) SE earthquakes near Park County
Teton County, WY 90 km (56 mi) S earthquakes near Teton County
Gallatin County, MT 98 km (61 mi) NW earthquakes near Gallatin County
Carbon County, MT 111 km (69 mi) ENE earthquakes near Carbon County
Sweet Grass County, MT 111 km (69 mi) NNE earthquakes near Sweet Grass County

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

Aftershocks so far

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

  1. 2.1 23 km SSW of Mammoth, Wyoming
  2. 1.6 33 km E of West Yellowstone, Montana
  3. 3.2 22 km SSW of Mammoth, Wyoming
  4. 1.8 33 km E of West Yellowstone, Montana
  5. 3.1 23 km SSW of Mammoth, Wyoming
  6. 2.0 33 km E of West Yellowstone, Montana
  7. 1.9 33 km S of Mammoth, Wyoming
  8. 1.7 33 km E of West Yellowstone, Montana
  9. 2.5 33 km E of West Yellowstone, Montana
  10. 1.5 23 km SSW of Mammoth, Wyoming
  11. 1.7 23 km SSW of Mammoth, Wyoming
  12. 1.9 23 km SSW of Mammoth, Wyoming
  13. 1.6 23 km SSW of Mammoth, Wyoming
  14. 2.1 23 km SSW of Mammoth, Wyoming
  15. 1.8 23 km SSW of Mammoth, Wyoming

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.