QuakeIndex

Earthquake · reviewed by a seismologist

M 2.8ml

Earthquake near Star Valley Ranch, WY

No earthquake was likely felt in Star Valley Ranch in the 24 hours to 7:43 am MST (14:43 UTC). The last one was M 3.8, 75 km (47 mi) SSW, at 5:05 am MDT on 15 May 2026, estimated intensity II (weak) in town; 29 felt reports to USGS. Every earthquake near Star Valley Ranch

This page: a magnitude 2.8 earthquake was recorded 18 km (11 mi) northeast of Star Valley Ranch, WY, at 8:39 am MDT on 26 October 2023 (14:39 UTC), 5.0 km deep.

USGS: 18 km NE of Star Valley Ranch, Wyoming

8:39 am MDT, Oct 26, 2023 · · 5.0 km deep · released about 480 lb of TNT

10 km30 km60 km120 km N Caribou County 70 kmSublette County 77 kmBonneville County 78 kmTeton County 85 kmLincoln County 93 kmBear Lake County 98 kmMadison County 107 kmTeton County 113 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
8:39 am MDT on 26 October 2023 ()
Where
18 km (11 mi) northeast of Star Valley Ranch, WY · earthquakes near Star Valley Ranch
Magnitude
M 2.8 (ml)
Depth
5.0 km below the surface
Felt
no reports yet
Nearest
Caribou County, 70 km WSW
Nearest mapped fault
Greys River fault, 10 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 1042 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

At this magnitude and depth, people at rest would likely notice it out to about 27 km (17 mi) from the epicentre. In Star Valley Ranch, 18 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.

Likely felt in: Star Valley Ranch 18 km, intensity II · Hoback 24 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 480 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 32,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 22,000× the energy of this one
  3. Around the size people start to feel M 3.0 2× the energy of this one
  4. This earthquake M 2.8 about 480 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 4.8 on 2016-08-27 — about 1,000 times the energy of this one.

Before 2016, the USGS record lists 2 earthquakes of M5 or more within 50 km:

  1. 5.8 4 km SSE of Auburn, Wyoming · 38 km SSW of this epicentre
  2. 5.3 Southeastern Idaho · 43 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 43.0677, -110.7730. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Caribou County, ID 70 km (44 mi) WSW earthquakes near Caribou County
Sublette County, WY 77 km (48 mi) ESE earthquakes near Sublette County
Bonneville County, ID 78 km (48 mi) WNW earthquakes near Bonneville County
Teton County, ID 85 km (53 mi) NNW earthquakes near Teton County
Lincoln County, WY 93 km (58 mi) S earthquakes near Lincoln County
Bear Lake County, ID 98 km (61 mi) SSW earthquakes near Bear Lake County

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

Aftershocks so far

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

  1. 1.7 11 km W of Bondurant, Wyoming
  2. 2.2 12 km ESE of South Park, Wyoming
  3. 2.0 9 km ESE of Alpine Northeast, Wyoming
  4. 2.3 3 km NNE of Star Valley Ranch, Wyoming
  5. 2.8 5 km NE of Star Valley Ranch, Wyoming
  6. 1.7 5 km N of Alpine Northeast, Wyoming
  7. 2.2 12 km NNW of Alpine Northeast, Wyoming
  8. 1.7 19 km NW of Bondurant, Wyoming
  9. 2.4 11 km E of Jackson, Wyoming
  10. 2.0 16 km ENE of Etna, Wyoming
  11. 2.9 14 km E of Jackson, Wyoming
  12. 2.9 14 km E of Jackson, Wyoming
  13. 3.9 15 km E of Jackson, Wyoming
  14. 2.7 10 km W of Fairview, Wyoming
  15. 3.0 7 km W of Thayne, 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.