A. General comments 1. Gravity is an agent of erosion and transport of rocks and regolith. The resulting downward movement of materials is called mass wasting . Frequently, water interacts with gravity to produce mass wasting. After heavy rains, saturated hillslopes are heavier and subject to slope failure.
Water often acts as a lubricant along the base of the mass movement.
Gravity acts to restore oversteepened slopes to some stable angle. The steepest slope angle that can be maintained without slipping downward is called the angle of repose . Slopes that exceed the angle of repose are geologically unstable and subject to mass wasting. Generally speaking, gravity acts as a denudational force to reduce slope steepness and increase roundness of slopes. The fallen material that accumulates by mass wasting is subject to further weathering and erosion by other agents.