Wikipedia: New Madrid Fault Zone

The New Madrid Fault Zone is an source of earthquakes? which lies along the Mississippi River. The zone is named after the town of New Madrid, Missouri, the site of three of the most severe North American earthquakes in recorded history. These earthquakes, which occured in late 1811 and early 1812, were quite strong, causing changes in the course of the Mississippi and were reported to have been felt as far away as Boston.

The last major earthquake to occur in this region occured in Charleston, Missouri in 1895, and is estimated to have had a magnitude of 6.7 on the [Richter Scale]?.