12. This slide gives an overview of the location of the New Madrid seismic zone and also shows epicenters and liquefaction from the 1811-1812 earthquakes. The slide illustrates the extent of the tremendous liquefaction caused by the earthquakes. The field setting in the meizoseismal region was almost ideal for forming liquefaction features because the region is generally underlain by thick (commonly 30 m) river alluvium of clean medium sand that is overlain by a relatively thin cap of silt and clay (ranging in thickness from 2 to 10 m), and the water table was typically only a meter or so in depth at the time of the earthquake.