QuakeIndex

Earthquake · reviewed by a seismologist

M 3.3ml

28 km E of La Sal, Utah

Yes. A magnitude 3.3 earthquake was recorded 28 km E of La Sal, Utah, at 6:53 pm MST on 19 December 2020 (01:53 UTC), less than 1 km deep. 5 people have reported feeling it to USGS.

· 0.8 km deep · released about 1.4 tons of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N San Miguel County 52 kmMontrose County 59 kmDolores County 71 kmMesa County 92 kmGrand County 96 kmOuray County 100 kmSan Juan County 107 kmMontezuma County 108 kmDelta 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
Magnitude
M 3.3 (ml)
Depth
0.8 km below the surface
Felt
5 reports · strongest reported intensity II
Nearest
San Miguel County, 52 km SE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2084 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 53 km (33 mi) from the epicentre. 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.

How big was it?

This earthquake released about 1.4 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.3 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 120,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 5,400× the energy of this one
  3. Magna, Utah 2020 M 5.7 3,800× the energy of this one
  4. This earthquake M 3.3 about 1.4 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 2.9× more

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

The largest earthquake within 50 km since 2016 was M 4.5 on 2019-03-04 — about 59 times the energy of this one.

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 38.2767, -108.9220. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
San Miguel County, CO 52 km (33 mi) SE earthquakes near San Miguel County
Montrose County, CO 59 km (37 mi) ENE earthquakes near Montrose County
Dolores County, CO 71 km (44 mi) SSE earthquakes near Dolores County
Mesa County, CO 92 km (57 mi) NNE earthquakes near Mesa County
Grand County, UT 96 km (60 mi) NW earthquakes near Grand County
Ouray County, CO 100 km (62 mi) E earthquakes near Ouray County

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

Aftershocks so far

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

  1. 1.5 26 km ESE of La Sal, Utah
  2. 2.0 29 km E of La Sal, Utah
  3. 1.6 28 km ESE of La Sal, Utah
  4. 2.1 28 km E of La Sal, Utah
  5. 2.2 28 km E of La Sal, Utah
  6. 2.0 28 km E of La Sal, Utah
  7. 2.1 28 km E of La Sal, Utah
  8. 1.6 30 km E of La Sal, Utah
  9. 1.5 29 km E of La Sal, Utah
  10. 1.5 29 km E of La Sal, Utah
  11. 2.1 20 km WSW of Naturita, Colorado
  12. 1.7 28 km E of La Sal, Utah
  13. 2.3 29 km E of La Sal, UT
  14. 1.9 28 km E of La Sal, Utah
  15. 1.7 28 km E of La Sal, 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.