mining explosion · reviewed by a seismologist
M 3.0ml
27 km NNE of Jeffrey City, Wyoming
- When
- Magnitude
- M 3.0 (ml)
- Depth
- 0.0 km below the surface
- Felt
- 2 reports · strongest reported intensity III
- Nearest
- Fremont County, 78 km WNW
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 1799 days ago
A magnitude 3.0 earthquake was recorded 27 km NNE of Jeffrey City, Wyoming at 04:19 UTC on 2021-08-17. 2 people have reported feeling it to USGS. This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.
USGS catalogues this as mining explosion, not an earthquake.
How big was it?
This earthquake released about 950 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.0 would have released about 32 times as much.
- Northridge, California 1994 M 6.7 350,000× the energy of this one
- Mineral, Virginia 2011 M 5.8 16,000× the energy of this one
- Magna, Utah 2020 M 5.7 11,000× the energy of this one
- This earthquake M 3.0 about 950 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 42.7407, -107.7558. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Fremont County, WY | 78 km (48 mi) | WNW | earthquakes near Fremont County |
| Natrona County, WY | 85 km (53 mi) | ENE | earthquakes near Natrona County |
| Hot Springs County, WY | 122 km (76 mi) | NNW | earthquakes near Hot Springs County |
| Carbon County, WY | 134 km (83 mi) | SSE | earthquakes near Carbon County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
4 earthquakes have been recorded within 50 km since this one.
- 2.9 37 km NNE of Jeffrey City, Wyoming
- 2.6 37 km SE of Riverton, Wyoming
- 2.5 44 km SE of Shoshoni, Wyoming
- 2.6 35 km ESE of Shoshoni, 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.