U.S. state profile · USGS ComCat
Earthquakes in Illinois
Illinois has catalogued 3 M4+ earthquakes since 2005 (ranked 26th of 39 U.S. states), with the strongest reaching magnitude M5.2.
Illinois ranks 26th of 39 U.S. states and territories by catalogued seismic activity - a state with limited seismic activity, averaging about 0 M4+ events a year alongside 0 significant M6+ earthquakes since 1900. Below: the full M6+ event history, magnitude and depth profile, and yearly trend.
- 3
- M4+ events (since 2005)
- 0
- Major M6+ (since 1900)
- M5.2
- Strongest
- ~0
- M4+ per year
The verdict
Illinois is below the global median in catalogued seismic activity, with 3 M4+ earthquakes logged since 2005 and 0 major M6+ events since 1900, the strongest reaching magnitude 5.2.
- N/A
- no yearly breakdown available
- N/A
- average recorded event depth
- 0%
- of events are shallow (<70 km, the most damaging kind)
Average catalogued magnitude is 4.6 - most events are moderate tremors felt but rarely damaging. On the M4+ activity ladder Arkansas sits immediately above at 5 events and Missouri sits immediately below at 2.
USGS state event tape
Event tape IL · Illinois M4+ · 26th/39
Illinois · 3 M4+ · max M5.2 · 0 M6+
- TAPE 3
- EPIC 26th/39
- YOY M5.2
- BAND 0
- STRIP near Arkansas
- BOOK Apr 21, 2008
Stamps derive from this jurisdiction's USGS ComCat row (M4+ book, rank, peak magnitude, M6+ record, ladder neighbour, depth/peak year), not a hazard forecast. PlainQuake is informational only - not professional advice and not a substitute for official USGS guidance. See our disclaimer. Verify with USGS ComCat → · Read with methodology → · How earthquakes are measured → · Most active U.S. regions → · All state catalog rows → · States ranked →
Where Illinois sits in the catalog
Rank 26th of 39 tracked U.S. states and territories (31th percentile by M4+ count since 2005). On the M4+ activity ladder Arkansas sits immediately above at 5 events and Missouri sits immediately below at 2.
No M6+ events on the significant record
Illinois has catalogued M4+ activity since 2005 but zero magnitude-6.0-and-above events in the USGS significant series back to 1900. The nearest tracked jurisdiction that does carry an M6+ record is Arizona (7 M4+ · 3 M6+).
Same M4+ count, broken by peak magnitude
2 tracked jurisdictions share Illinois's exact catalogued count of 3 M4+ events since 2005. Among that cohort, Illinois ranks 1st of 2 by strongest recorded magnitude (M5.2).
| State | M4+ count | Strongest |
|---|---|---|
| Illinois (this page) | 3 | M5.2 |
| Tennessee | 3 | M4.4 |
Seismic hazard context
Catalogued counts on this page are history, not a building-code hazard map. Illinois's latest M4+ catalog entry is dated Apr 21, 2008. For the national PGA design-basis tiers, see the seismic risk maps guide or the USGS National Seismic Hazard Model.
Other states in this catalog sample
A Illinois-keyed shuffle of the full 38-state roster (not the six nearest by count), so adjacent quiet states do not share the same comparison set.
Peak-magnitude sample from the same roster
A second Illinois-keyed shuffle of states with a recorded max magnitude (independent order from the frequency sample above).
According to the US Geological Survey Earthquake Hazards Program, PlainQuake's figures are rendered directly from 317,293 recorded M4+ earthquakes and 14,444 significant M6+ events (USGS ComCat, 2005-present) -- no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 2026-08-26.