Faults are cracks in the Earth’s surface, found where earthquakes occur. There are three basic types of faults: normal, reverse and strike-slip. The type of a fault tells us about the forces acting upon it.
In a normal fault, the blocks either side of the fault are being pulled away from each other. The blocks move in the direction you would expect gravity to move them normally.
A reverse fault is similar to a normal fault, except the fault blocks are moving towards each other.
In a strike-slip fault (also called a wrench or transcurrent fault) the blocks move alongside each other. The San Andreas fault in California and the North Anatolian fault in Turkey are both strike-slip faults.