Faults are classified three different ways: normal, reverse, and strike-slip.
Normal faults are no more normal than the others, though they were once thought to be. They occur when the end of one plate slides vertically down the end of another.
A reverse fault describes the opposite motion: when one plate end moves vertically up the end of another plate.
A strike-slip fault appears when two plate ends slide past each other horizontally.
Plate movements can be both vertical and horizontal at the same time, producing what is known as an oblique fault.