Earthquake · reviewed by a seismologist
M 1.6ml
Earthquake near Star Valley Ranch, WY
No earthquake was likely felt in Star Valley Ranch in the 24 hours to 9:10 am MST (16:10 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 1.6 earthquake was recorded 17 km (11 mi) north-northwest of Star Valley Ranch, WY, at 9:41 pm MDT on 28 July 2021 (03:41 UTC), 1.4 km deep.
USGS: 5 km SSW of Alpine, Wyoming
- When
- 9:41 pm MDT on 28 July 2021 ()
- Where
- 17 km (11 mi) north-northwest of Star Valley Ranch, WY · earthquakes near Star Valley Ranch
- Magnitude
- M 1.6 (ml)
- Depth
- 1.4 km below the surface
- Felt
- no reports yet
- Nearest
- Caribou County, 56 km SW
- Nearest mapped fault
- Grand Valley fault, 3 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 1931 days ago
Earthquake alerts for Star Valley Ranch, WY
Get a notification in this browser when USGS records an earthquake near Star Valley Ranch, WY. No account or email needed.
Alerts are on for .
Not a warning. An alert comes after USGS publishes a quake, usually minutes after the shaking. For early warning use ShakeAlert, through your phone's Wireless Emergency Alerts or the MyShake app.
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. In Star Valley Ranch, 17 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.
Earthquakes near other towns within 30 km: Hoback.
How big was it?
This earthquake released about 7.8 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.
- Mineral, Virginia 2011 M 5.8 1,900,000× the energy of this one
- Magna, Utah 2020 M 5.7 1,400,000× the energy of this one
- Around the size people start to feel M 3.0 120× the energy of this one
- This earthquake M 1.6 about 7.8 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 3 earthquakes of M5 or more within 50 km:
- 5.8 4 km SSE of Auburn, Wyoming · 40 km S of this epicentre
- 5.3 Southeastern Idaho · 25 km WSW of this epicentre
- 5.3 29 km WSW of Freedom, Idaho · 37 km SW 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 43.1180, -111.0315. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Caribou County, ID | 56 km (35 mi) | SW | earthquakes near Caribou County |
| Bonneville County, ID | 57 km (35 mi) | WNW | earthquakes near Bonneville County |
| Teton County, ID | 73 km (45 mi) | NNW | earthquakes near Teton County |
| Madison County, ID | 90 km (56 mi) | NW | earthquakes near Madison County |
| Bear Lake County, ID | 96 km (59 mi) | SSW | earthquakes near Bear Lake County |
| Sublette County, WY | 99 km (61 mi) | ESE | earthquakes near Sublette County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
54 earthquakes have been recorded within 50 km since this one.
- 2.6 12 km NE of Star Valley Ranch, Wyoming
- 2.2 11 km NE of Star Valley Ranch, Wyoming
- 2.6 13 km NE of Star Valley Ranch, Wyoming
- 2.4 Wyoming
- 2.3 11 km NE of Star Valley Ranch, Wyoming
- 2.1 27 km SSW of Irwin, Idaho
- 3.3 10 km W of Hoback, Wyoming
- 2.8 7 km WSW of Hoback, Wyoming
- 1.9 15 km W of Freedom, Idaho
- 3.3 13 km W of Freedom, Idaho
- 2.8 13 km W of Freedom, Idaho
- 2.3 12 km W of Fairview, Wyoming
- 1.6 12 km WNW of Fairview, Wyoming
- 2.4 6 km W of Hoback, Wyoming
- 1.7 4 km ENE of Hoback, 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
- The official USGS event page — the source of record for every value above
- Did you feel it? Report it to USGS — reports go to USGS, not to us
- ShakeMap for this event, when USGS has produced one
QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.