QuakeIndex

Earthquake · reviewed by a seismologist

M 2.1md

Arizona

Yes. A magnitude 2.1 earthquake was recorded in Arizona, 15 km (9 mi) SSE of St. George, UT, at 6:51 am MST on 9 January 2021 (13:51 UTC), 19 km deep.

15 km (9 mi) SSE of St. George, UT

· 19 km deep · released about 40 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Washington County 34 kmIron County 107 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
19 km below the surface
Felt
no reports yet
Nearest
Washington County, 34 km N
Nearest mapped fault
Washington fault, 1 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 2132 days ago

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

At this magnitude and depth it was probably too small to be felt, even directly above it. 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: Saint George, Washington, Santa Clara, Ivins.

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.

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 2 earthquakes of M5 or more within 50 km:

  1. 6.3 Near Pine Valley, Utah · 49 km N of this epicentre
  2. 5.9 3 km SSE of Washington, Utah · 16 km N 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 36.9573, -113.5020. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Washington County, UT 34 km (21 mi) N earthquakes near Washington County
Iron County, UT 107 km (67 mi) N earthquakes near Iron County

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

Aftershocks so far

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

  1. 1.7 1 km NW of Toquerville, Utah
  2. 1.8 13 km SSW of Saint George, Utah
  3. 1.9 11 km ESE of Pine Valley, Utah
  4. 2.9 10 km SSE of Washington, Utah
  5. 1.7 14 km NE of Beaver Dam, Arizona
  6. 1.7 13 km NE of Beaver Dam, Arizona
  7. 2.3 10 km N of Beaver Dam, Arizona
  8. 1.6 10 km W of Ivins, Utah
  9. 1.6 16 km SW of Apple Valley, Utah
  10. 2.1 14 km NNE of Beaver Dam, Arizona
  11. 1.8 14 km NNE of Beaver Dam, Arizona
  12. 1.6 18 km WSW of Santa Clara, Utah
  13. 1.7 13 km SSW of Saint George, Utah
  14. 1.5 14 km N of Beaver Dam, Arizona
  15. 1.9 13 km S of Saint George, 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.