This document discusses different types of faults that occur due to brittle deformation of the Earth's crust. It describes normal faults which form rift valleys, reverse/thrust faults where older rocks are thrust over younger rocks, and strike-slip faults where the rock on one side of the fault moves horizontally past the other side in a left or right lateral motion. Examples given include the East African Rift valley formed by normal faults, reverse faults in Japan and thrust faults in Scotland.