Movement of a large mass of rock, soil and debris downward due to the pull of gravity.
These changes can happen suddenly (as in one minute the rock is there and the next it is gone, or it can happen slowly over time).
Gravity is constantly trying to pull rock and debris down the slope of a mountain
Slumps and rockslides
The process of a slump is the sliding of coherent rock material along a curved surface whole the process of a rockslide is the sliding of rock ,arterial down a mountain.
Debris flow and earthflow
Debris flow: the movement of a water-laden mass of loose mud, sand, soil, rock and debris down a slope
Earth flow: a flow of fine grained material that typically develops at the lower end of a slope