Three types of faults are normal faults, reverse faults and strike-slip faults. A fault's type depends on the kinds of forces acting upon it. A fault is a crack or fracture of the Earth's crust where movement occurs in the rock on either side of the crack.
In a normal fault, the hanging wall, or upper side, of the fault drops down. The forces involved move the sides apart.
In a reverse fault, the opposite happens, and the hanging wall moves in an upward direction. The forces push the sides together.
In strike-slip faults, the walls move from side to side instead of in an up or down direction. No hanging wall exists in this type of fault.
