Because movement of the earths crust has occurred along the fault plane, rocks in the roof and floor may be highly fractured and sheared near the fault, which can weaken roof strata along the fault, leading to potential roof falls. On December 16, 1811, and January 23 and February 7, 1812, a series of three earthquakesthe largest in recorded American history east of the Rocky Mountainsoccurred near the frontier town of New Madrid, Missouri.