QuakeIndex

Earthquake · reviewed by a seismologist

M 2.1md

9 km E of Thompsonville, Illinois

· 7.8 km deep · released about 44 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Hamilton County 20 kmSaline County 21 kmFranklin County 25 kmWilliamson County 33 kmGallatin County 41 kmWhite County 45 kmJefferson County 48 kmJohnson County 55 kmHardin County 57 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 2.1 (md)
Depth
7.8 km below the surface
Felt
1 report · strongest reported intensity I
Nearest
Hamilton County, 20 km NNE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 983 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage. 1 person has reported feeling it to USGS.

How big was it?

This earthquake released about 44 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.1 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 340,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 240,000× the energy of this one
  3. Around the size people start to feel M 3.0 22× the energy of this one
  4. This earthquake M 2.1 about 44 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.

Where

Epicentre 37.9245, -88.6532. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Hamilton County, IL 20 km (13 mi) SSW of here earthquakes near Hamilton County
Saline County, IL 21 km (13 mi) NNW of here earthquakes near Saline County
Franklin County, IL 25 km (16 mi) ESE of here earthquakes near Franklin County
Williamson County, IL 33 km (20 mi) NE of here earthquakes near Williamson County
Gallatin County, IL 41 km (26 mi) WNW of here earthquakes near Gallatin County
White County, IL 45 km (28 mi) WSW of here earthquakes near White County

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

Aftershocks so far

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

  1. 2.4 4 km NNE of Valier, Illinois
  2. 2.4 4 km WSW of Enfield, Illinois

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.