QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8ml

Earthquake near Magna, UT

No earthquake was likely felt in Magna in the 24 hours to 4:27 pm MST (23:27 UTC). The last one was M 2.2, 6 km (3 mi) ENE, at 8:46 am MDT on 17 June 2026, estimated intensity II (weak) in town; 28 felt reports to USGS. Every earthquake near Magna

This page: a magnitude 1.8 earthquake was recorded 18 km (11 mi) north-northwest of Magna, UT, at 7:23 pm MDT on 18 August 2021 (01:23 UTC), 3.0 km deep.

USGS: 18 km NNW of Magna, Utah

24 km (15 mi) WNW of Salt Lake City, UT

7:23 pm MDT, Aug 18, 2021 · · 3.0 km deep · released about 14 lb of TNT

Every earthquake near Magna Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Davis County 20 kmSalt Lake County 31 kmWeber County 53 kmMorgan County 58 kmTooele County 90 kmUtah County 93 kmSummit County 103 kmCache County 104 kmWasatch County 105 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
7:23 pm MDT on 18 August 2021 ()
Where
18 km (11 mi) north-northwest of Magna, UT · earthquakes near Magna
Magnitude
M 1.8 (ml)
Depth
3.0 km below the surface
Felt
no reports yet
Nearest
Davis County, 20 km N
Nearest mapped fault
Great Salt Lake fault, 2 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 1912 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 13 km (8 mi) from the epicentre. In Magna, 18 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: North Salt Lake, West Valley City, West Bountiful, Woods Cross, Stansbury park, Bountiful.

How big was it?

This earthquake released about 14 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,100,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 760,000× the energy of this one
  3. Around the size people start to feel M 3.0 68× the energy of this one
  4. This earthquake M 1.8 about 14 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

The largest earthquake within 50 km since 2016 was M 5.7 on 2020-03-18 — about 760,000 times the energy of this one.

Before 2016, the USGS record lists 2 earthquakes of M5 or more within 50 km:

  1. 5.3 Near Salt Lake City, Utah · 37 km ESE of this epicentre
  2. 5.0 1 km NE of Magna, Utah · 18 km SSE 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 40.8588, -112.1903. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Davis County, UT 20 km (12 mi) N earthquakes near Davis County
Salt Lake County, UT 31 km (19 mi) SE earthquakes near Salt Lake County
Weber County, UT 53 km (33 mi) NNE earthquakes near Weber County
Morgan County, UT 58 km (36 mi) ENE earthquakes near Morgan County
Tooele County, UT 90 km (56 mi) WSW earthquakes near Tooele County
Utah County, UT 93 km (58 mi) SSE earthquakes near Utah 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. 1.6 5 km NE of Magna, Utah
  2. 1.8 13 km ESE of Centerville, Utah
  3. 1.8 3 km WSW of Bluffdale, Utah
  4. 1.5 9 km S of Morgan, Utah
  5. 1.6 9 km S of Morgan, Utah
  6. 1.8 1 km SE of Bluffdale, Utah
  7. 1.7 3 km ENE of Magna, Utah
  8. 1.6 2 km SE of North Salt Lake, Utah
  9. 1.5 6 km NE of Magna, Utah
  10. 2.6 15 km NNW of Summit Park, Utah
  11. 1.7 5 km ENE of Magna, Utah
  12. 2.5 5 km ENE of Magna, Utah
  13. 2.3 3 km S of Bluffdale, Utah
  14. 1.6 3 km S of Bluffdale, Utah
  15. 1.5 3 km S of Bluffdale, 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.