QuakeIndex

Earthquake · reviewed by a seismologist

M 2.6ml

Earthquake near Riverton, WY

No earthquake was likely felt in Riverton in the 24 hours to 10:35 pm MST (05:35 UTC). The last one was M 3.8, 54 km (34 mi) S, at 5:38 pm MST on 12 December 2025, estimated intensity II (weak) in town; 50 felt reports to USGS. Every earthquake near Riverton

This page: a magnitude 2.6 earthquake was recorded 37 km (23 mi) southeast of Riverton, WY, at 11:57 am MDT on 27 May 2025 (17:57 UTC), 5.0 km deep.

USGS: 37 km SE of Riverton, Wyoming

11:57 am MDT, May 27, 2025 · · 5.0 km deep · released about 240 lb of TNT

10 km30 km60 km120 km N Fremont County 54 kmNatrona County 105 kmHot Springs County 106 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
11:57 am MDT on 27 May 2025 ()
Where
37 km (23 mi) southeast of Riverton, WY · earthquakes near Riverton
Magnitude
M 2.6 (ml)
Depth
5.0 km below the surface
Felt
no reports yet
Nearest
Fremont County, 54 km WNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 457 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 23 km (14 mi) from the epicentre. In Riverton, 37 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 240 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.6 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 63,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 45,000× the energy of this one
  3. Around the size people start to feel M 3.0 4× the energy of this one
  4. This earthquake M 2.6 about 240 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 since 1900 lists no earthquake of M5 or more within 50 km.

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 42.8097, -108.0336. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Fremont County, WY 54 km (34 mi) WNW earthquakes near Fremont County
Natrona County, WY 105 km (65 mi) E earthquakes near Natrona County
Hot Springs County, WY 106 km (66 mi) NNW earthquakes near Hot Springs County
Washakie County, WY 122 km (76 mi) NNE earthquakes near Washakie County

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

Aftershocks so far

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

  1. 3.8 29 km E of Atlantic City, Wyoming
  2. 2.5 29 km ENE of Atlantic City, Wyoming
  3. 2.9 37 km NNE of Jeffrey City, 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.