Earthquake · reviewed by a seismologist
M 1.9ml
Earthquake near Afton, WY
No earthquake was likely felt in Afton in the 24 hours to 1:06 am MST (08:06 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 1.9 earthquake was recorded 8 km (5 mi) south-southeast of Afton, WY, at 11:52 am MDT on 11 July 2018 (17:52 UTC), 13 km deep.
USGS: 3 km NNE of Smoot, Wyoming
- When
- 11:52 am MDT on 11 July 2018 ()
- Where
- 8 km (5 mi) south-southeast of Afton, WY · earthquakes near Afton
- Magnitude
- M 1.9 (ml)
- Depth
- 13 km below the surface
- Felt
- no reports yet
- Nearest
- Lincoln County, 50 km SSE
- Nearest mapped fault
- Grand Valley fault, 1 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 3046 days ago
Earthquake alerts for Afton, WY
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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 9 km (6 mi) from the epicentre. In Afton, 8 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 25 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.0 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 600,000× the energy of this one
- Magna, Utah 2020 M 5.7 420,000× the energy of this one
- Around the size people start to feel M 3.0 38× the energy of this one
- This earthquake M 1.9 about 25 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 110,000 times the energy of this one.
Before 2016, the USGS record lists one earthquake of M5 or more within 50 km:
- 5.8 4 km SSE of Auburn, Wyoming · 13 km NNW 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 42.6525, -110.9048. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Lincoln County, WY | 50 km (31 mi) | SSE | earthquakes near Lincoln County |
| Bear Lake County, ID | 54 km (33 mi) | SW | earthquakes near Bear Lake County |
| Caribou County, ID | 54 km (34 mi) | WNW | earthquakes near Caribou County |
| Sublette County, WY | 82 km (51 mi) | E | earthquakes near Sublette County |
| Franklin County, ID | 92 km (57 mi) | SW | earthquakes near Franklin County |
| Bonneville County, ID | 101 km (63 mi) | NW | earthquakes near Bonneville 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.
- 1.7 3 km NW of Georgetown, Idaho
- 1.5 3 km N of Georgetown, Idaho
- 2.0 14 km ESE of Soda Springs, Idaho
- 1.8 13 km E of Soda Springs, Idaho
- 1.6 15 km E of Soda Springs, Idaho
- 2.4 18 km SW of Fairview, Wyoming
- 1.8 13 km NNW of Georgetown, Idaho
- 2.5 18 km W of Fairview, Wyoming
- 1.7 10 km NNW of Georgetown, Idaho
- 2.4 11 km NNW of Georgetown, Idaho
- 1.5 10 km NNW of Georgetown, Idaho
- 1.8 13 km NNW of Georgetown, Idaho
- 2.2 13 km NNW of Georgetown, Idaho
- 1.6 8 km NW of Georgetown, Idaho
- 1.6 14 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.