Earthquake · reviewed by a seismologist
M 3.0mb_lg
8 km E of Agar, South Dakota
- When
- Magnitude
- M 3.0 (mb_lg)
- Depth
- 5.0 km below the surface
- Felt
- no reports yet
- Nearest
- Sully County, 19 km SW
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 3239 days ago
This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.
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.
Where
Epicentre 44.8394, -99.9628. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction | |
|---|---|---|---|
| Sully County, SD | 19 km (12 mi) | NE of here | earthquakes near Sully County |
| Potter County, SD | 24 km (15 mi) | S of here | earthquakes near Potter County |
| Hughes County, SD | 51 km (31 mi) | N of here | earthquakes near Hughes County |
| Hyde County, SD | 51 km (32 mi) | NW of here | earthquakes near Hyde County |
| Walworth County, SD | 66 km (41 mi) | S of here | earthquakes near Walworth County |
| Faulk County, SD | 68 km (43 mi) | WSW of here | earthquakes near Faulk County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
No further earthquakes have 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.