Mass movement is the bulk movement of rock and soil debris down a slope in response to gravity or the sinking of the Earth's surface in a vertical direction. This process may also be referred to as mass wasting.
Water plays a role in sinking mass movements and mass movements on slopes. Both types of movements play a role in the changing of landforms. Mass wasting once referred to processes that involved large masses of crusted material moved from one place to another by gravity. Its definition was later changed to include the sinking of confined places of the Earth and mass-wasting processes.