QuakeIndex

Earthquake · reviewed by a seismologist

M 2.1mb_lg

Earthquake near Hot Springs, SD

No earthquake was likely felt in Hot Springs in the 24 hours to 8:03 pm MST (03:03 UTC). The last one was M 3.6, 31 km (19 mi) NNE, at 8:14 pm MST on 8 March 2025, estimated intensity III (weak) in town; 7 felt reports to USGS. Every earthquake near Hot Springs

This page: a magnitude 2.1 earthquake was recorded 17 km (11 mi) northeast of Hot Springs, SD, at 2:49 am MDT on 1 August 2022 (08:49 UTC), 11 km deep. 4 people have reported feeling it to USGS.

USGS: 3 km N of Buffalo Gap, South Dakota

2:49 am MDT, Aug 1, 2022 · · 11 km deep · released about 43 lb of TNT

10 km30 km60 km120 km N Custer County 22 kmFall River County 38 kmOglala Lakota County 64 kmPennington County 66 kmDawes County 92 kmLawrence County 100 kmNiobrara County 107 kmWeston County 108 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
2:49 am MDT on 1 August 2022 ()
Where
17 km (11 mi) northeast of Hot Springs, SD · earthquakes near Hot Springs
Magnitude
M 2.1 (mb_lg)
Depth
11 km below the surface
Felt
4 reports · strongest reported intensity III
Nearest
Custer County, 22 km NW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1492 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth, people at rest would likely notice it out to about 26 km (16 mi) from the epicentre. In Hot Springs, 17 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 43 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.1 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 350,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 250,000× the energy of this one
  3. Around the size people start to feel M 3.0 22× the energy of this one
  4. This earthquake M 2.1 about 43 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 43.5265, -103.3082. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Custer County, SD 22 km (13 mi) NW earthquakes near Custer County
Fall River County, SD 38 km (23 mi) SSW earthquakes near Fall River County
Oglala Lakota County, SD 64 km (40 mi) ESE earthquakes near Oglala Lakota County
Pennington County, SD 66 km (41 mi) NE earthquakes near Pennington County
Dawes County, NE 92 km (57 mi) S earthquakes near Dawes County
Lawrence County, SD 100 km (62 mi) NNW earthquakes near Lawrence County

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

Aftershocks so far

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

  1. 3.6 7 km W of Fairburn, South Dakota
  2. 2.9 7 km NNE of Buffalo Gap, 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.