Gravity is the primary force driving mass movement, which is the downslope movement of soil, rock, and organic material under the influence of gravity. When materials are on a slope, gravity pulls them downward, which can lead to various types of mass movement, such as landslides, rockfalls, and mudslides.
As gravity acts on the hillside, it creates stress on the slope materials. When this stress exceeds the strength of the materials, they begin to move. The steepness of the slope, the type of material, and the amount of water present can all influence how gravity affects mass movement. For instance, when water saturates the soil, it can reduce friction and increase the likelihood of movement. This is why heavy rain or snowmelt often triggers landslides.
In summary, gravity is the driving force behind mass movement, causing materials to shift and flow downslope. Understanding the role of gravity helps in predicting and managing the risks associated with mass movements, especially in areas prone to such events.