QuakeIndex

mining explosion · reviewed by a seismologist

M 2.3ml

Earthquake near Ishpeming, MI

No earthquake was likely felt in Ishpeming in the 24 hours to 1:01 pm EST (18:01 UTC). The last one was M 2.6, 12 km (8 mi) SSW, at 12:48 pm EDT on 2 June 2021, estimated intensity III (weak) in town. Every earthquake near Ishpeming

No: USGS classifies this as a mining explosion, not an earthquake. A magnitude 2.3 mining explosion was recorded 38 km (24 mi) south-southwest of Ishpeming, MI, at 2:40 pm EST on 9 December 2017 (19:40 UTC), less than 1 km deep.

USGS: 28 km SSE of Republic, Michigan

2:40 pm EST, Dec 9, 2017 · · 0.0 km deep · released about 85 lb of TNT

10 km30 km60 km120 km N Dickinson County 17 kmIron County 53 kmFlorence County 54 kmMarquette County 58 kmBaraga County 71 kmMenominee County 75 kmDelta County 83 kmForest County 91 kmMarinette County 92 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
2:40 pm EST on 9 December 2017 ()
Where
38 km (24 mi) south-southwest of Ishpeming, MI · earthquakes near Ishpeming
Magnitude
M 2.3 (ml)
Depth
0.0 km below the surface
Felt
no reports yet
Nearest
Dickinson County, 17 km S
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3181 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 37 km (23 mi) from the epicentre. In Ishpeming, 38 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.

USGS catalogues this as mining explosion, not an earthquake.

How big was it?

This earthquake released about 85 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.3 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 180,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 130,000× the energy of this one
  3. Around the size people start to feel M 3.0 11× the energy of this one
  4. This earthquake M 2.3 about 85 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 46.1664, -87.8474. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Dickinson County, MI 17 km (11 mi) S earthquakes near Dickinson County
Iron County, MI 53 km (33 mi) W earthquakes near Iron County
Florence County, WI 54 km (34 mi) SW earthquakes near Florence County
Marquette County, MI 58 km (36 mi) NNE earthquakes near Marquette County
Baraga County, MI 71 km (44 mi) NNW earthquakes near Baraga County
Menominee County, MI 75 km (47 mi) SSE earthquakes near Menominee County

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

Aftershocks so far

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

  1. 2.6 11 km S of West Ishpeming, Michigan
  2. 2.2 1 km WSW of Ishpeming, Michigan
  3. 2.2 2 km SSW of Ishpeming, Michigan

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.