Surprised this isn't in the news more considering the earthquake in Haiti:
http://www.nytimes.com/2010/02/11/us/11chicago.html 3.8 magnitude
For a bit of history:
http://en.wikipedia.org/wiki/1812_New_Madrid_earthquake
Forgot to add this one since it's directly related to the main story:
http://en.wikipedia.org/wiki/Wabash_Valley_Seismic_Zone