Illinois is at risk from two major seismic zones, the Wabash Valley Seismic Zone and the New Madrid Seismic Zone (NMSZ). The Wabash Valley Zone is located between southeastern Illinois and southwestern Indiana. The NMSZ is located in the Central Mississippi Valley and includes portions of the states of Alabama, Arkansas, Illinois, Indiana, Kentucky, Missouri, Mississippi, and Tennessee. During any 50-year time span, there is a 25% to 40% chance of a magnitude 6.0 or greater earthquake in this seismic zone. Since 1974, the year network monitoring of seismic activity began, more than 3000 earthquakes have been recorded in the NMSZ. Fortunately, none of these earthquakes exceeded a magnitude of 5.0, and most occurred without our noticing. The largest earthquake in recent years occurred on the Wabash Valley Seismic Zone. This earthquake registered a magnitude of 5.4 and occurred in Mt. Carmel, Illinois on April 18th, 2008.
Did you know that the most powerful earthquakes ever to occur in the continental United States took place in the NMSZ during the winter of 1811-1812? At that time, the area of the seismic zone was scarcely populated. Experts estimate that a similar series of earthquakes today would devastate the region, with projected damages of $60 to $80 billion. This website is dedicated to making citizens more aware of the earthquake hazard in their backyard and to informing them about what they can do before, during, and after an earthquake.