QuakeIndex

Earthquake · reviewed by a seismologist

M 2.1md

Earthquake near Thayer, MO

No earthquake was likely felt in Thayer in the 24 hours to 10:47 am CST (16:47 UTC). The last one was M 2.2, 30 km (18 mi) WSW, at 9:10 pm CST on 1 November 2026, estimated intensity II (weak) in town. Every earthquake near Thayer

This page: a magnitude 2.1 earthquake was recorded 12 km (7 mi) southwest of Thayer, MO, at 9:39 pm CDT on 9 August 2020 (02:39 UTC), 5.0 km deep.

USGS: 9 km SW of Mammoth Spring, Arkansas

9:39 pm CDT, Aug 9, 2020 · · 5.0 km deep · released about 51 lb of TNT

10 km30 km60 km120 km N Fulton County 18 kmSharp County 33 kmOregon County 34 kmHowell County 43 kmIzard County 47 kmRandolph County 55 kmBaxter County 65 kmLawrence County 65 kmRipley County 71 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
9:39 pm CDT on 9 August 2020 ()
Where
12 km (7 mi) southwest of Thayer, MO · earthquakes near Thayer
Magnitude
M 2.1 (md)
Depth
5.0 km below the surface
Felt
no reports yet
Nearest
Fulton County, 18 km WSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2283 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 30 km (19 mi) from the epicentre. In Thayer, 12 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.

Earthquakes near other towns within 30 km: Cherokee Village, Highland, Ash Flat, Horseshoe Bend.

How big was it?

This earthquake released about 51 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 5.8 300,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 210,000× the energy of this one
  3. Around the size people start to feel M 3.0 19× the energy of this one
  4. This earthquake M 2.1 about 51 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 36.4453, -91.6305. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Fulton County, AR 18 km (11 mi) WSW earthquakes near Fulton County
Sharp County, AR 33 km (21 mi) SSE earthquakes near Sharp County
Oregon County, MO 34 km (21 mi) NE earthquakes near Oregon County
Howell County, MO 43 km (27 mi) NNW earthquakes near Howell County
Izard County, AR 47 km (29 mi) SSW earthquakes near Izard County
Randolph County, AR 55 km (34 mi) ESE earthquakes near Randolph County

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

Aftershocks so far

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

  1. 2.2 7 km ENE of West Plains, Missouri
  2. 2.3 7 km SSW of Ravenden, Arkansas
  3. 2.1 9 km NNW of Ravenden Springs, Arkansas
  4. 1.8 2 km W of Imboden, Arkansas
  5. 2.2 6 km WNW of West Plains, Missouri
  6. 2.3 4 km SE of Franklin, Arkansas
  7. 2.0 3 km SSW of Imboden, Arkansas
  8. 3.1 4 km SSW of Imboden, Arkansas
  9. 2.1 18 km WNW of Maynard, Arkansas
  10. 2.3 6 km WSW of Ravenden, Arkansas
  11. 1.7 Missouri-Arkansas border region
  12. 1.7 2 km WSW of Imboden, Arkansas
  13. 2.1 2 km SE of Ravenden, Arkansas
  14. 1.9 3 km ESE of Ravenden, Arkansas
  15. 1.8 Missouri-Arkansas border region

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.