QuakeIndex

Earthquake · reviewed by a seismologist

M 2.6ml

Earthquake near Richfield, UT

No earthquake was likely felt in Richfield in the 24 hours to 11:29 pm MST (06:29 UTC). The last one was M 3.2, 34 km (21 mi) W, at 8:35 am MDT on 22 April 2026, estimated intensity II (weak) in town; 6 felt reports to USGS. Every earthquake near Richfield

This page: a magnitude 2.6 earthquake was recorded 23 km (14 mi) southeast of Richfield, UT, at 9:07 pm MST on 13 December 2021 (04:07 UTC), 3.7 km deep. 2 people have reported feeling it to USGS.

USGS: 12 km N of Koosharem, Utah

9:07 pm MST, Dec 13, 2021 · · 3.7 km deep · released about 240 lb of TNT

10 km30 km60 km120 km N Sevier County 16 kmPiute County 38 kmSanpete County 88 kmWayne County 89 kmGarfield County 97 kmEmery County 111 kmMillard County 113 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
9:07 pm MST on 13 December 2021 ()
Where
23 km (14 mi) southeast of Richfield, UT · earthquakes near Richfield
Magnitude
M 2.6 (ml)
Depth
3.7 km below the surface
Felt
2 reports · strongest reported intensity IV
Nearest
Sevier County, 16 km NNE
Nearest mapped fault
Annabella graben faults, 14 km from its surface trace — near is not the same as on
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1722 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 23 km (14 mi) from the epicentre. In Richfield, 23 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.

Likely felt in: Monroe 19 km, intensity II · Richfield 23 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 240 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.6 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 63,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 45,000× the energy of this one
  3. Around the size people start to feel M 3.0 4× the energy of this one
  4. This earthquake M 2.6 about 240 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 lists 4 earthquakes of M5 or more within 50 km:

  1. 6.6 Near Marysvale, Utah · 45 km WSW of this epicentre
  2. 5.2 0 km SSW of Central Valley, Utah · 19 km WNW of this epicentre
  3. 5.2 25 km SE of Salina, Utah · 34 km NE of this epicentre
  4. 5.0 10 km NE of Marysvale, Utah · 24 km WSW of this epicentre

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 38.6260, -111.9030. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Sevier County, UT 16 km (10 mi) NNE earthquakes near Sevier County
Piute County, UT 38 km (23 mi) SSW earthquakes near Piute County
Sanpete County, UT 88 km (55 mi) NNE earthquakes near Sanpete County
Wayne County, UT 89 km (55 mi) ESE earthquakes near Wayne County
Garfield County, UT 97 km (60 mi) SSE earthquakes near Garfield County
Emery County, UT 111 km (69 mi) ENE earthquakes near Emery County

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

Aftershocks so far

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

  1. 1.6 11 km E of Kingston, Utah
  2. 1.5 4 km SE of Aurora, Utah
  3. 1.5 5 km SE of Aurora, Utah
  4. 1.6 27 km WSW of Emery, Utah
  5. 1.7 10 km NNW of Junction, Utah
  6. 1.7 27 km SW of Emery, Utah
  7. 1.9 6 km S of Joseph, Utah
  8. 2.0 29 km SW of Emery, Utah
  9. 2.0 16 km W of Marysvale, Utah
  10. 1.5 17 km W of Marysvale, Utah
  11. 1.9 7 km S of Kanosh, Utah
  12. 1.8 5 km WSW of Richfield, Utah
  13. 1.8 4 km WNW of Joseph, Utah
  14. 1.5 9 km SSE of Joseph, Utah
  15. 2.0 7 km SSE of Joseph, Utah

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.