Downslope movements of rock or sediment as a result of gravity. Movement is classified as rapid if it can be detected by eye. Type of material (is it rock or is it soil) Speed of movement (velocity ranging from a few millimeters per year to 360km/h) Rock of sediment dropping off the face of the cliff. Downslope movement along a discrete (straight/flat) failure plan. Movement of particles semi-independently of one another, usually with the aid of water. This mass movement is caused by a fall mechanism. It involves rock rolling down a steep slope or falling through air. Happens quickly, with very little warning aside from a visible crack in the rock right before it falls. This mass movement is caused by a slide mechanism. In a slump, the failure plane is sloped upward. Usually caused by added weight (water, vegetation, infrastructure etc. ) Occurs very rapidly just like a fall, with very little warning.