Earthquake · reviewed by a seismologist
M 2.8ml
Earthquake near Greybull, WY
No earthquake was likely felt in Greybull in the 24 hours to 5:28 am MST (12:28 UTC). The last one was M 2.8, 24 km (15 mi) E, at 12:57 am MDT on 23 March 2023, estimated intensity II (weak) in town. Every earthquake near Greybull
This page: a magnitude 2.8 earthquake was recorded 24 km (15 mi) east of Greybull, WY, at 12:57 am MDT on 23 March 2023 (06:57 UTC), 11 km deep.
USGS: 8 km S of Shell, Wyoming
- When
- 12:57 am MDT on 23 March 2023 ()
- Where
- 24 km (15 mi) east of Greybull, WY · earthquakes near Greybull
- Magnitude
- M 2.8 (ml)
- Depth
- 11 km below the surface
- Felt
- no reports yet
- Nearest
- Big Horn County, 20 km WNW
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 1265 days ago
Earthquake alerts for Greybull, 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 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 25 km (16 mi) from the epicentre. In Greybull, 24 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: Basin.
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.
- Mineral, Virginia 2011 M 5.8 32,000× the energy of this one
- Magna, Utah 2020 M 5.7 22,000× the energy of this one
- Around the size people start to feel M 3.0 2× the energy of this one
- 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
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 44.4600, -107.7618. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Big Horn County, WY | 20 km (12 mi) | WNW | earthquakes near Big Horn County |
| Washakie County, WY | 65 km (40 mi) | S | earthquakes near Washakie County |
| Sheridan County, WY | 78 km (49 mi) | ENE | earthquakes near Sheridan County |
| Hot Springs County, WY | 98 km (61 mi) | SSW | earthquakes near Hot Springs County |
| Johnson County, WY | 104 km (65 mi) | ESE | earthquakes near Johnson County |
| Big Horn County, MT | 107 km (67 mi) | N | earthquakes near Big Horn County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
1 earthquake has been recorded within 50 km since this one.
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.