QuakeIndex

Earthquake · reviewed by a seismologist

M 2.1md

12 km ESE of Mammoth Spring, Arkansas

· 4.9 km deep · released about 40 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Oregon County 27 kmSharp County 30 kmFulton County 36 kmRandolph County 37 kmLawrence County 53 kmRipley County 54 kmHowell County 56 kmIzard County 59 kmCarter County 70 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 2.1 (md)
Depth
4.9 km below the surface
Felt
1 report · strongest reported intensity II
Nearest
Oregon County, 27 km N
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2128 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage. 1 person has reported feeling it to USGS.

How big was it?

This earthquake released about 40 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 5.8 380,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 270,000× the energy of this one
  3. Around the size people start to feel M 3.0 24× the energy of this one
  4. This earthquake M 2.1 about 40 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 36.4440, -91.4190. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Oregon County, MO 27 km (17 mi) S of here earthquakes near Oregon County
Sharp County, AR 30 km (19 mi) N of here earthquakes near Sharp County
Fulton County, AR 36 km (23 mi) E of here earthquakes near Fulton County
Randolph County, AR 37 km (23 mi) WNW of here earthquakes near Randolph County
Lawrence County, AR 53 km (33 mi) NNW of here earthquakes near Lawrence County
Ripley County, MO 54 km (33 mi) WSW of here earthquakes near Ripley County

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

Aftershocks so far

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

  1. 2.0 4 km SW of Powhatan, Arkansas
  2. 2.1 5 km N of Black Rock, Arkansas
  3. 1.6 8 km NW of Strawberry, Arkansas
  4. 1.8 3 km N of Black Rock, Arkansas
  5. 1.6 8 km WNW of Strawberry, Arkansas
  6. 2.3 5 km NNW of Strawberry, Arkansas
  7. 2.1 9 km NNW of Ravenden Springs, Arkansas
  8. 1.8 2 km W of Imboden, Arkansas
  9. 2.0 Missouri-Arkansas border region
  10. 2.0 2 km NNW of Black Rock, Arkansas
  11. 1.6 1 km WNW of Lynn, Arkansas
  12. 1.7 1 km WNW of Lynn, Arkansas
  13. 2.5 4 km SSW of Maynard, Arkansas
  14. 2.8 0.4 km ESE of Maynard, Arkansas
  15. 2.3 4 km SE of Franklin, Arkansas

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.