QuakeIndex

Earthquake · reviewed by a seismologist

M 2.9mb_lg

7 km NNE of Buffalo Gap, South Dakota

· 7.5 km deep · released about 680 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Custer County 22 kmFall River County 42 kmPennington County 61 kmOglala Lakota County 61 kmDawes County 94 kmLawrence County 99 kmWeston County 110 kmNiobrara County 112 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
Magnitude
M 2.9 (mb_lg)
Depth
7.5 km below the surface
Felt
1 report · strongest reported intensity III
Nearest
Custer County, 22 km NW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 765 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 1 person has reported feeling it to USGS.

How big was it?

This earthquake released about 680 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.9 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 22,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 16,000× the energy of this one
  3. Around the size people start to feel M 3.0 1.4× the energy of this one
  4. This earthquake M 2.9 about 680 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 43.5511, -103.2585. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Custer County, SD 22 km (14 mi) SE of here earthquakes near Custer County
Fall River County, SD 42 km (26 mi) NNE of here earthquakes near Fall River County
Pennington County, SD 61 km (38 mi) SW of here earthquakes near Pennington County
Oglala Lakota County, SD 61 km (38 mi) WNW of here earthquakes near Oglala Lakota County
Dawes County, NE 94 km (58 mi) N of here earthquakes near Dawes County
Lawrence County, SD 99 km (61 mi) SSE of here earthquakes near Lawrence 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.

  1. 3.6 7 km W of Fairburn, South Dakota

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.