M3.8 Earthquake in the Illinois-Indiana border region — June 17, 2021
2021-06-17 19:18:02 UTC (2021-06-17) · approx. 1:18 PM UTC-6 local
Felt by 4,062 people across a wide area. Maximum shaking intensity MMI 4.7 (moderate).
On June 17, 2021 at 19:18 UTC, a magnitude 3.8 shallow crustal earthquake struck in the Illinois-Indiana border region, at a depth of 6.3 km and coordinates 39.8305°, -87.2867°. The earthquake was reported felt by 4,062 peopleacross a wide area, with a maximum shaking intensity of Modified Mercalli Intensity (MMI) 4.7 (moderate). This earthquake was detected by 21 seismic stations with excellent location accuracy and was assigned a USGS significance rating of 714, making it a moderate-impact event.
Physical scale: An earthquake of magnitude 3.8 releases seismic energy equivalent to roughly 8.1 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 260 m — a useful intuition for the size of the slip patch on the fault.
What the Shaking Felt Like
At MMI 4.7 (moderate), people in the most strongly affected areas would have experienced: Mild shaking, similar to a passing truck. Hanging objects swing. Glasses and dishes may rattle. Not commonly felt outdoors.
ShakeMap — predicted shaking intensity
Modeled ground-motion intensity contoured on the Modified Mercalli scale (MMI). Computed by the USGS from the moment-tensor solution and regional ground-motion prediction equations.
Source: U.S. Geological Survey ShakeMap. View interactive ShakeMap on USGS
Did You Feel It? — community-reported shaking
Aggregated felt-report intensity from 4,062 citizen responses to the USGS Did You Feel It? system. Each colored zone represents the average MMI from reports in that area.
Source: U.S. Geological Survey Did You Feel It?. View on USGS · submit your own report
Earthquake Details
-87.2867°E
Technical Information
Common Questions
How strong was the magnitude 3.8 earthquake in the Illinois-Indiana border region?
The magnitude 3.8 earthquake that struck in the Illinois-Indiana border region on June 17, 2021 at 19:18 UTC had a depth of 6.3 km. It was felt by 4,062 people with maximum shaking intensity of MMI 4.7 (moderate). For context, this was a minor earthquake typically detected only by instruments.
Where did the earthquake occur?
The earthquake epicenter was located at 39.8305°, -87.2867°, which is in the Illinois-Indiana border region.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 3.8 earthquakes can continue for several days and gradually diminish over time.
Authoritative source: USGS event page (event ID: nm60344372). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, June 17, 2021). M3.8 Earthquake in the Illinois-Indiana border region — June 17, 2021. Retrieved May 2, 2026 from https://www.earthquaketracker.org/earthquakes/event/nm60344372/