Mass wasting, also known as mass movement, is the movement of rock or soil down slopes under the force of gravity. It differs from other processes of erosion in that the debris transported by mass wasting is not entrained in a moving medium, such as water, wind, or ice. Mass wasting occurs on both terrestrial and submarine slopes, and has been observed on Earth, Mars, Venus, Jupiters moon Io, and on many other bodies in the Solar System.

There are different types of mass wasting, each with its own characteristic features and taking place over timescales from seconds to hundreds of years. The most common types of mass wasting are:

• Creep: This is the slowest type of mass wasting, where soil particles move downhill imperceptibly slowly due to gravity.

• Solifluction: This is a type of creep that occurs in areas with permafrost, where the soil thaws during the summer and becomes saturated with water, causing it to flow downhill.

• Rockfalls: This is the sudden and rapid movement of rock down a steep slope or cliff.

• Debris flows: This is the rapid movement of a mixture of soil, rock, and water down a slope.

• Landslides: This is the movement of a mass of rock, debris, or soil down a slope under the influence of gravity.

Mass wasting is a common phenomenon throughout the Solar System, occurring where volatile materials are lost from a regolith. Slope stability is determined by two factors: the angle of the slope and the shear strength of the accumulated materials. Mass-wasting events are triggered by changes that oversteepen slope angles and weaken slope stability, such as heavy rainfall, earthquakes, volcanic eruptions, and human activities.