<P> The New Madrid fault system was responsible for the 1811--12 New Madrid earthquakes and has the potential to produce large earthquakes in the future . Since 1812, frequent smaller earthquakes have been recorded in the area . </P> <P> Earthquakes that occur in the New Madrid Seismic Zone potentially threaten parts of eight American states: Illinois, Indiana, Missouri, Arkansas, Kentucky, Tennessee, Oklahoma and Mississippi . </P> <P> The 150 - mile (240 km) long seismic zone, which extends into five states, stretches southward from Cairo, Illinois; through Hayti, Caruthersville and New Madrid in Missouri; through Blytheville into Marked Tree in Arkansas . It also covers a part of West Tennessee, near Reelfoot Lake, extending southeast into Dyersburg . It is southwest of the Wabash Valley Seismic Zone . </P> <P> Most of the seismicity originates between 3 and 15 miles (4.8 and 24.1 km) beneath the Earth's surface . </P>

Where does the new madrid fault line run