QuakeIndex

Earthquake · reviewed by a seismologist

M 2.4ml

Earthquake near Salt Lake City, UT

USGS: 11 km SSW of Henefer, Utah

35 km (22 mi) ENE of Salt Lake City, UT · 34 km (21 mi) NE of Millcreek, UT

9:53 pm MDT, Sep 8, 2018 · · 8.7 km deep · released about 130 lb of TNT

10 km30 km60 km120 km N Morgan County 18 kmSalt Lake County 41 kmWeber County 46 kmSummit County 51 kmDavis County 54 kmWasatch County 74 kmRich County 83 kmUtah County 90 kmCache County 91 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
9:53 pm MDT on 8 September 2018 ()
Where
33 km (20 mi) NE of Salt Lake City, UT · earthquakes near Salt Lake City
Magnitude
M 2.4 (ml)
Depth
8.7 km below the surface
Felt
no reports yet
Nearest
Morgan County, 18 km N
Nearest mapped fault
Main Canyon fault, 5 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 2944 days ago

A magnitude 2.4 earthquake was recorded 33 km (20 mi) NE of Salt Lake City, UT, at 9:53 pm MDT on 8 September 2018 (03:53 UTC). This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

Earthquakes near other towns within 30 km: Coalville, Morgan, Summit Park, Silver Summit, Centerville, Snyderville.

How big was it?

This earthquake released about 130 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.4 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 120,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 83,000× the energy of this one
  3. Around the size people start to feel M 3.0 7.4× the energy of this one
  4. This earthquake M 2.4 about 130 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. 5.3 Near Salt Lake City, Utah · 32 km SW of this epicentre
  2. 5.0 1 km NE of Magna, Utah · 49 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 40.9268, -111.5697. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Morgan County, UT 18 km (11 mi) N earthquakes near Morgan County
Salt Lake County, UT 41 km (26 mi) SW earthquakes near Salt Lake County
Weber County, UT 46 km (29 mi) NW earthquakes near Weber County
Summit County, UT 51 km (32 mi) E earthquakes near Summit County
Davis County, UT 54 km (34 mi) WNW earthquakes near Davis County
Wasatch County, UT 74 km (46 mi) SSE earthquakes near Wasatch County

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

Aftershocks so far

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

  1. 2.0 6 km NE of Magna, Utah
  2. 2.0 5 km NE of Magna, Utah
  3. 1.9 7 km NNE of Magna, Utah
  4. 1.9 7 km NE of Magna, Utah
  5. 2.3 7 km NNE of Magna, Utah
  6. 3.5 5 km NNE of Magna, Utah
  7. 1.9 5 km NNE of Magna, Utah
  8. 2.0 6 km NNE of Magna, Utah
  9. 2.4 6 km NE of Magna, Utah
  10. 3.9 6 km NE of Magna, Utah
  11. 3.1 7 km NE of Magna, Utah
  12. 3.1 5 km NE of Magna, Utah
  13. 2.5 6 km NE of Magna, Utah
  14. 2.3 7 km NNE of Magna, Utah
  15. 3.7 4 km N of Magna, 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.