While earthquakes are often associated with the West Coast, seismic activity also occurs in the Midwestern United States. Illinois, despite its inland location, experiences tremors, some strong enough to be felt by residents.
Illinois’ Most Recent Seismic Activity
The most recent felt earthquake centered in Illinois occurred on Monday, May 12, 2025. This 3.3 magnitude tremor was confirmed near Lerna in Coles County shortly before 11:45 p.m. While shaking was reported, emergency services received no calls for damage or assistance. Earthquakes of this magnitude cause minimal to no damage. Most seismic events in Illinois are minor, often below magnitude 3, and are imperceptible to the general public.
Understanding Illinois’ Seismic Landscape
The geological context for earthquakes in Illinois involves two major intraplate seismic zones: the New Madrid Seismic Zone and the Wabash Valley Seismic Zone. Intraplate earthquakes occur within a tectonic plate, unlike those at plate boundaries. The New Madrid Seismic Zone (NMSZ) stretches approximately 150 miles through the central Mississippi Valley, encompassing parts of southern Illinois, Missouri, Arkansas, Kentucky, and Tennessee. This zone is characterized by deep thrust faults, remnants of an ancient rift where the Earth’s crust began to pull apart millions of years ago.
The Wabash Valley Seismic Zone (WVSZ) is centered along the lower Wabash River valley, bordering southeastern Illinois and southwestern Indiana. This zone features vertically oriented faults buried beneath layers of sediment, linked to the ancient New Madrid aulacogen, an old rift system. Both the NMSZ and WVSZ are active, with the NMSZ averaging around 200 seismic events annually, though most are too small to be detected without sensitive instruments. Earthquakes in the central United States, including those affecting Illinois, can be felt over a significantly larger area compared to quakes of similar magnitude in the western U.S., due to differences in the underlying bedrock.
Significant Earthquakes in Illinois History
Illinois has experienced several historically significant earthquakes that demonstrate the region’s seismic potential. The most powerful sequence occurred between December 1811 and February 1812, known as the New Madrid Earthquakes. These three major events, with estimated magnitudes reaching 7.0 to 8.0, were among the largest recorded in North American history. The immense shaking caused ground warping, fissures, and temporarily altered the course of the Mississippi River. Although Illinois was sparsely populated, settlers felt the violent tremors.
A more recent and widely felt event was the 1968 Illinois earthquake, which struck on November 9, 1968, measuring 5.3 magnitude. Centered near Norris City in southern Illinois, this quake caused considerable structural damage, including toppled chimneys, and was felt as far away as Chicago. It was felt across 23 states, covering approximately 580,000 square miles. Another notable event occurred on April 18, 2008, when a 5.2 magnitude earthquake in the Wabash Valley Seismic Zone near Mount Carmel was felt across at least 16 states, resulting in minor damage across Illinois, Indiana, and Kentucky.