In a fault, the moving of a hanging wall down relative to the footwall is a normal dip-slip. The slip is normal because the force of gravity moves a higher object to a lower position. The normal dip-slip extends the fault line.
In some cases, the hanging wall moves upward relative to the footwall; however, to make the upward vertical movement, the forces causing the movement are required to overcome gravity and friction. This type of movement is a reverse-slip. Reverse-slips shorten the fault line.
Horizontal movements at fault lines are strike-slips. Geologists refer to movement occurring both horizontally and vertically at the same time as oblique-slips.