The New Madrid Seismic Zone, sometimes called the New Madrid Fault Line, (pronounced New MAD-rid) is a major seismic zone and a prolific source of intraplate earthquakes (earthquakes within a tectonic plate) in the Southern and Midwestern United States stretching to the southwest from New Madrid, Missouri.
The San Andreas Fault is a continental transform fault that runs a length of roughly 1,300 kilometers (810 mi) through California in the United States. The fault's motion is right-lateral strike-slip (horizontal motion). It forms the tectonic boundary between the Pacific Plate and the North American Plate.