QuakeIndex

Earthquake · reviewed by a seismologist

M 1.7ml

45 km SSE of Mammoth, Wyoming

Yes. A magnitude 1.7 earthquake was recorded 45 km SSE of Mammoth, Wyoming, at 9:50 pm MDT on 3 July 2021 (03:50 UTC), 4.3 km deep.

· 4.3 km deep · released about 9.3 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Park County 65 kmTeton County 66 kmPark County 92 kmFremont County 99 kmGallatin County 115 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
Magnitude
M 1.7 (ml)
Depth
4.3 km below the surface
Felt
no reports yet
Nearest
Park County, 65 km ESE
Nearest mapped fault
Eagle Bay fault, 13 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 1954 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 11 km (7 mi) from the epicentre. 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 lists 12 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.5 14 km N of Madison Junction, Wyoming · 42 km WNW of this epicentre
  2. 6.3 22 km SW of Mammoth, Wyoming · 42 km WNW of this epicentre
  3. 6.0 21 km E of West Yellowstone, Montana · 36 km W of this epicentre
  4. 5.9 26 km SSE of Mammoth, Wyoming · 21 km NW of this epicentre
  5. 5.7 13 km SSW of Mammoth, Wyoming · 38 km NW 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 44.6387, -110.3870. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Park County, WY 65 km (40 mi) ESE earthquakes near Park County
Teton County, WY 66 km (41 mi) S earthquakes near Teton County
Park County, MT 92 km (57 mi) N earthquakes near Park County
Fremont County, ID 99 km (61 mi) WSW earthquakes near Fremont County
Gallatin County, MT 115 km (72 mi) NNW earthquakes near Gallatin County
Teton County, ID 118 km (73 mi) SW earthquakes near Teton County

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

Aftershocks so far

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

  1. 1.7 64 km ESE of West Yellowstone, Montana
  2. 2.2 64 km ESE of West Yellowstone, Montana
  3. 1.5 62 km ESE of West Yellowstone, Montana
  4. 1.6 63 km ESE of West Yellowstone, Montana
  5. 1.6 62 km ESE of West Yellowstone, Montana
  6. 1.8 63 km ESE of West Yellowstone, Montana
  7. 2.0 64 km ESE of West Yellowstone, Montana
  8. 1.6 63 km ESE of West Yellowstone, Montana
  9. 1.7 64 km ESE of West Yellowstone, Montana
  10. 2.4 65 km ESE of West Yellowstone, Montana
  11. 2.0 64 km ESE of West Yellowstone, Montana
  12. 1.5 63 km ESE of West Yellowstone, Montana
  13. 1.6 65 km SSE of Mammoth, Wyoming
  14. 2.1 64 km ESE of West Yellowstone, Montana
  15. 1.9 63 km ESE 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.