Faults are breaks in the ground caused by the movement of plates.
Different types of faults can be found at plate boundaries as the plates crack and buckle under enormous pressures.
There are three types of fault:
Top: normal fault, middle: reverse fault, bottom: strike-slip fault.
At a normal fault, the rocks either side of the fault pull apart, causing one side to slide downwards. This usually happens at divergent plate boundaries where plates pull apart from each other.
At a reverse fault, the rocks either side of the fault push into each other. This causes one to be thrust upwards. This usually happens at convergent plate boundaries, where plates push into each other.
At a strike-slip fault, the rocks either side of the fault slide past each other, horizontally. This usually happens at transform plate boundaries where plates rub past each other.