The removal of mass, also known as tilt movement, mass displacement or mass movement, is the geomorphological process by which soil, regolith and rock move downhill by the force of gravity. Types of mass removal include creep, landslides, flows and falls, each with its own characteristics, and which takes place on time scales from seconds to years. Mass removal occurs on both terrestrial and submarine slopes, and has been observed on Earth, Mars, Venus and on Jupiter's satellite, Io. When the gravitational force acting on a slope exceeds its lack of resistance to force, the slope (mass removal) occurs. The strength of the slope material, the cohesion and the amount of internal friction between the material support to maintain the stability of the slope and collectively known as the resistance to cut the slope. The greater non-cohesive angle of a slope that can be maintained without losing its stability is known as the angle of repose. When a slope has this angle, its resistance to the cut perfectly balances the force of gravity acting on it. Mass removal can occur at a very slow rate, particularly in areas that are very dry or areas that receive sufficient rainfall for vegetation to stabilize on the surface. It can also occur at a very high speed, such as in rock slides and landslides, with disastrous consequences both immediate and delayed, for example as a result of the formation of landslide dams. Factors that modify the potential of the mass include: changes in the angle of the slope, the weakening of the material by erosion, higher water content, changes in vegetation cover, and overload.

mass removal has many aerodynamic agents with wind, gravity, water, sun, living organisms and others.

wiki