QuakeIndex

Earthquake · reviewed by a seismologist

M 2.8md

Earthquake near Harrison, AR

No earthquake was likely felt in Harrison in the 24 hours to 8:07 pm CST (02:07 UTC). The last one was M 5.0, 708 km (440 mi) W, at 5:21 am CDT on 23 July 2026, estimated intensity II (weak) in town; 499 felt reports to USGS. Every earthquake near Harrison

This page: a magnitude 2.8 earthquake was recorded 21 km (13 mi) east of Harrison, AR, at 5:54 am CST on 3 December 2021 (11:54 UTC), 4.6 km deep. 146 people have reported feeling it to USGS.

USGS: 2 km W of Pyatt, Arkansas

5:54 am CST, Dec 3, 2021 · · 4.6 km deep · released about 400 lb of TNT

10 km30 km60 km120 km N Marion County 18 kmBoone County 19 kmSearcy County 42 kmTaney County 47 kmNewton County 48 kmBaxter County 49 kmOzark County 58 kmCarroll County 60 kmStone County 76 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
5:54 am CST on 3 December 2021 ()
Where
21 km (13 mi) east of Harrison, AR · earthquakes near Harrison
Magnitude
M 2.8 (md)
Depth
4.6 km below the surface
Felt
146 reports · strongest reported intensity IV
Nearest
Marion County, 18 km E
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1733 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

At this magnitude and depth, people at rest would likely notice it out to about 59 km (37 mi) from the epicentre. In Harrison, 21 km away, the estimate is intensity III (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.

Likely felt in: Harrison 21 km, intensity III. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 400 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 38,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 27,000× the energy of this one
  3. Around the size people start to feel M 3.0 2.4× the energy of this one
  4. This earthquake M 2.8 about 400 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 36.2478, -92.8773. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Marion County, AR 18 km (11 mi) E earthquakes near Marion County
Boone County, AR 19 km (12 mi) WNW earthquakes near Boone County
Searcy County, AR 42 km (26 mi) SSE earthquakes near Searcy County
Taney County, MO 47 km (29 mi) NNW earthquakes near Taney County
Newton County, AR 48 km (30 mi) SW earthquakes near Newton County
Baxter County, AR 49 km (31 mi) E earthquakes near Baxter County

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

Aftershocks so far

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

  1. 2.1 13 km E of South Lead Hill, Arkansas
  2. 2.4 3 km E of Yellville, Arkansas
  3. 2.1 2 km E of Mountain Home, Arkansas
  4. 1.7 7 km WSW of Bull Shoals, Arkansas
  5. 2.1 7 km S of Jasper, Arkansas
  6. 2.4 4 km E of Diamond City, Arkansas
  7. 2.1 6 km ESE of Pontiac, Missouri
  8. 2.2 14 km NE of Pelsor, Arkansas
  9. 2.3 14 km NE of Pelsor, Arkansas
  10. 2.4 14 km NE of Pelsor, Arkansas
  11. 2.0 14 km ENE of South Lead Hill, Arkansas
  12. 2.2 14 km E of South Lead Hill, Arkansas
  13. 1.9 13 km ENE of South Lead Hill, Arkansas
  14. 2.4 14 km E of South Lead Hill, Arkansas
  15. 1.9 14 km E of South Lead Hill, 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.