QuakeIndex

mining explosion · reviewed by a seismologist

M 2.8ml

Minnesota

No: USGS classifies this as a mining explosion, not an earthquake. A magnitude 2.8 mining explosion was recorded in Minnesota, at 12:30 pm CST on 11 December 2020 (18:30 UTC), less than 1 km deep.

· 0.0 km deep · released about 480 lb of TNT

10 km30 km60 km120 km N St. Louis County 40 kmItasca County 45 kmCarlton County 97 kmAitkin County 99 kmKoochiching County 106 kmCass County 114 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 2.8 (ml)
Depth
0.0 km below the surface
Felt
no reports yet
Nearest
St. Louis County, 40 km ENE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2091 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 62 km (39 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.

Earthquakes near other towns within 30 km: Hibbing, Keewatin, Chisholm.

USGS catalogues this as mining explosion, not an earthquake.

How big was it?

This earthquake released about 480 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 32,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 22,000× the energy of this one
  3. Around the size people start to feel M 3.0 2× the energy of this one
  4. This earthquake M 2.8 about 480 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 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 47.4489, -93.0114. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
St. Louis County, MN 40 km (25 mi) ENE earthquakes near St. Louis County
Itasca County, MN 45 km (28 mi) W earthquakes near Itasca County
Carlton County, MN 97 km (61 mi) SSE earthquakes near Carlton County
Aitkin County, MN 99 km (62 mi) SSW earthquakes near Aitkin County
Koochiching County, MN 106 km (66 mi) NNW earthquakes near Koochiching County
Cass County, MN 114 km (71 mi) WSW earthquakes near Cass County

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

Aftershocks so far

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

  1. 3.2 8 km N of Parkville, Minnesota
  2. 2.7 6 km N of Parkville, Minnesota
  3. 2.9 5 km N of Mountain Iron, Minnesota
  4. 3.0 2 km NNW of Mountain Iron, Minnesota
  5. 3.0 5 km NNE of Virginia, Minnesota
  6. 2.9 5 km N of Parkville, Minnesota
  7. 3.0 0 km ENE of Parkville, Minnesota
  8. 3.0 4 km NE of Kinney, Minnesota
  9. 2.8 5 km NNE of Parkville, Minnesota
  10. 3.1 1 km NE of Eveleth, Minnesota
  11. 3.0 3 km W of Mountain Iron, Minnesota
  12. 3.0 5 km NNE of Mountain Iron, Minnesota
  13. 3.0 6 km NNE of Kinney, Minnesota
  14. 3.2 1 km NE of Virginia, Minnesota
  15. 3.1 3 km NE of Parkville, Minnesota

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.