No major active fault lines exist in Iowa , and Iowa is one of the most seismically stable states in the U.S. With the exception of the 1968 Illinois earthquake which caused the water tower at Lineville to leak , no injuries or significant damage has ever been caused by earthquakes in Iowa . Occasional small earthquakes occur near Fremont County in the far southwest , and the Sioux City area can occasionally be shaken by nearby tremblors . Large earthquakes associated with the New Madrid Fault of far southern Illinois and Missouri can occasionally be felt in eastern Iowa . Recent earthquakes centered in Oklahoma have also been felt in Iowa , but have caused no damage
1968 Illinois earthquake
1968 Illinois earthquake
Geography of Iowa