Earthquake · reviewed by a seismologist
M 2.1ml
Earthquake near Afton, WY
No earthquake was likely felt in Afton in the 24 hours to 10:29 pm MST (05:29 UTC). The last one was M 2.3, 14 km (9 mi) W, at 3:44 pm MDT on 19 May 2026, estimated intensity II (weak) in town. Every earthquake near Afton
This page: a magnitude 2.1 earthquake was recorded 9 km (6 mi) south of Afton, WY, at 2:50 pm MST on 8 February 2021 (21:50 UTC), 25 km deep.
USGS: 4 km NW of Smoot, Wyoming
- When
- 2:50 pm MST on 8 February 2021 ()
- Where
- 9 km (6 mi) south of Afton, WY · earthquakes near Afton
- Magnitude
- M 2.1 (ml)
- Depth
- 25 km below the surface
- Felt
- no reports yet
- Nearest
- Bear Lake County, 50 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 2100 days ago
Earthquake alerts for Afton, WY
Get a notification in this browser when USGS records an earthquake near Afton, 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 it was probably too small to be felt, even directly above it. In Afton, 9 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 44 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.1 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 340,000× the energy of this one
- Magna, Utah 2020 M 5.7 240,000× the energy of this one
- Around the size people start to feel M 3.0 22× the energy of this one
- This earthquake M 2.1 about 44 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 5.3 on 2017-09-02 — about 61,000 times the energy of this one.
Before 2016, the USGS record lists 3 earthquakes of M5 or more within 50 km:
- 5.8 4 km SSE of Auburn, Wyoming · 13 km N of this epicentre
- 5.3 Southeastern Idaho · 48 km NW of this epicentre
- 5.3 29 km WSW of Freedom, Idaho · 48 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 42.6463, -110.9530. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Bear Lake County, ID | 50 km (31 mi) | SW | earthquakes near Bear Lake County |
| Caribou County, ID | 51 km (32 mi) | WNW | earthquakes near Caribou County |
| Lincoln County, WY | 51 km (32 mi) | SSE | earthquakes near Lincoln County |
| Sublette County, WY | 86 km (53 mi) | E | earthquakes near Sublette County |
| Franklin County, ID | 89 km (55 mi) | SW | earthquakes near Franklin County |
| Bonneville County, ID | 99 km (62 mi) | NNW | earthquakes near Bonneville County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
57 earthquakes have been recorded within 50 km since this one.
- 3.0 18 km NNW of Taylor, Wyoming
- 2.6 18 km NNW of Taylor, Wyoming
- 1.8 18 km NNW of Taylor, Wyoming
- 3.6 17 km NNW of Taylor, Wyoming
- 1.7 southern Idaho
- 2.3 18 km NNW of Taylor, Wyoming
- 2.8 18 km NNW of Taylor, Wyoming
- 2.2 southern Idaho
- 1.6 12 km WNW of Fairview, Wyoming
- 1.8 7 km NW of Georgetown, Idaho
- 1.6 11 km ESE of Soda Springs, Idaho
- 1.6 southern Idaho
- 1.5 southern Idaho
- 1.7 19 km WSW of Fairview, Wyoming
- 2.3 10 km E of Soda Springs, Idaho
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.