Final answer:
The New Madrid seismic zone is associated with the partial rifting of North America from around 750 million years ago when the supercontinent Rodinia was breaking apart.
Step-by-step explanation:
The New Madrid seismic zone in southeastern Missouri is related to faults that were created from the partial rifting of North America during the breakup of the supercontinent Rodinia, about 750 million years ago. This seismic zone is not a result of the subduction of the Farallon plate, the meteorite impact at the Cretaceous-Tertiary boundary, glaciation during the last Ice Age, or a rise in sea level during the Mississippian period. The process of rifting occurs when tectonic plates pull apart from each other, which can happen along rift zones on both land and in the oceans. As plates pull apart, molten rock rises to fill the space between them, forming new crust as seen in rift zones like the Mid-Atlantic ridge and the central African rift.