QuakeIndex

mining explosion · reviewed by a seismologist

M 3.2ml

Earthquake near Chisholm, MN

No earthquake was likely felt in Chisholm in the 24 hours to 2:55 pm CST (20:55 UTC). The last one was M 2.8, 30 km (19 mi) ENE, at 12:23 pm CDT on 2 July 2026, estimated intensity III (weak) in town. Every earthquake near Chisholm

No: USGS classifies this as a mining explosion, not an earthquake. A magnitude 3.2 mining explosion was recorded 6 km (3 mi) east-northeast of Chisholm, MN, at 12:15 pm CDT on 22 July 2021 (17:15 UTC), less than 1 km deep.

USGS: 3 km NW of Buhl, Minnesota

12:15 pm CDT, Jul 22, 2021 · · 0.0 km deep · released about 1,900 lb of TNT

10 km30 km60 km120 km N St. Louis County 24 kmItasca County 60 kmCarlton County 102 kmLake County 106 kmKoochiching County 109 kmAitkin County 111 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
12:15 pm CDT on 22 July 2021 ()
Where
6 km (3 mi) east-northeast of Chisholm, MN · earthquakes near Chisholm
Magnitude
M 3.2 (ml)
Depth
0.0 km below the surface
Felt
no reports yet
Nearest
St. Louis County, 24 km ENE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1874 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 190 km (118 mi) from the epicentre. In Chisholm, 6 km away, the estimate is intensity IV (light). 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, Mountain Iron, Parkville, Virginia, Eveleth, Keewatin.

USGS catalogues this as mining explosion, not an earthquake.

How big was it?

This earthquake released about 1,900 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.2 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 180,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 7,900× the energy of this one
  3. Magna, Utah 2020 M 5.7 5,600× the energy of this one
  4. This earthquake M 3.2 about 1,900 lb of TNT
  5. Around the size people start to feel M 3.0 this one released 2× 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

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 47.5118, -92.8181. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
St. Louis County, MN 24 km (15 mi) ENE earthquakes near St. Louis County
Itasca County, MN 60 km (37 mi) W earthquakes near Itasca County
Carlton County, MN 102 km (63 mi) S earthquakes near Carlton County
Lake County, MN 106 km (66 mi) E earthquakes near Lake County
Koochiching County, MN 109 km (68 mi) NW earthquakes near Koochiching County
Aitkin County, MN 111 km (69 mi) SSW earthquakes near Aitkin County

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

Aftershocks so far

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

  1. 2.8 11 km NNE of Parkville, Minnesota
  2. 2.5 5 km NW of Biwabik, Minnesota
  3. 2.6 6 km NW of Mountain Iron, Minnesota
  4. 2.7 4 km NW of Leonidas, Minnesota
  5. 2.6 4 km NNE of Virginia, Minnesota
  6. 2.8 3 km ENE of Virginia, Minnesota
  7. 2.5 3 km NNW of Parkville, Minnesota
  8. 2.7 2 km NNE of Kinney, Minnesota
  9. 2.9 7 km S of Buhl, Minnesota
  10. 2.9 6 km NNE of Kinney, Minnesota
  11. 2.7 4 km NNW of Buhl, Minnesota
  12. 2.6 4 km NNW of Mountain Iron, Minnesota
  13. 3.0 3 km N of Kinney, Minnesota
  14. 2.8 0 km SSE of Parkville, Minnesota
  15. 2.9 2 km N 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.