Earthquakes
Southern Illinois Earthquake Awareness Oct. 11–17: Two Seismic Zones Pose Risk
CAIRO, Ill. — Two major earthquake producing regions threaten portions of southern Illinois, where strong ground shaking could damage buildings, disrupt transportation and leave communities without es
By Sophie Caldwell · 2026-10-12T00:50:47.504Z
CAIRO, Ill. — Two major earthquake producing regions threaten portions of southern Illinois, where strong ground shaking could damage buildings, disrupt transportation and leave communities without essential services.
The hazard is receiving renewed attention during the Oct. 11–17 earthquake awareness period, ahead of Thursday's Great Central U.S. ShakeOut.
Southern Illinois faces exposure from both the New Madrid Seismic Zone and the Wabash Valley Seismic Zone. Their influence extends across the state's southern and southeastern counties.
Historic earthquakes demonstrate why the region remains a concern.
On Nov. 9, 1968, a magnitude 5.4 earthquake struck Hamilton County. The shaking caused damage across southern Illinois and was felt hundreds of miles away.
Another significant earthquake occurred near Mount Carmel on April 18, 2008. That magnitude 5.2 event sent tremors across much of the Midwest, shaking buildings far beyond its immediate epicenter.
Seismic hazards also extend into the Mississippi River floodplain near Cairo, where unconsolidated sediments can affect how earthquake waves travel through the ground.
Illinois emergency officials warn that recovery from a major earthquake could require considerably more preparation than a typical short term emergency.
The Illinois Emergency Management Agency recommends households prepare to remain self sufficient for at least two weeks following a significant earthquake.
A damaging event could disrupt roads, utilities, water supplies and emergency response operations.
On Thursday, Oct. 15, residents across Illinois can participate in the Great Central U.S. ShakeOut at 10:15 a.m. local time.
The Illinois State Geological Survey is promoting the exercise, which teaches participants to drop, cover and hold on during strong shaking.
Residents should also secure bookcases and heavy appliances, store emergency water and identify safe locations inside homes and workplaces.
Earthquakes cannot currently be predicted with enough precision to issue advance warnings of when they will occur.
For southern Illinois communities near the Ohio and Mississippi rivers, Thursday's drill offers an opportunity to prepare for a hazard capable of affecting the region with little warning.