How do rock layers influence where a translational slide occurs?

In the context of geology, a translational slide occurs when a mass of material moves downslope along one or more discrete shearing surfaces. Rock layers significantly influence where these slides take place by providing the structural weaknesses necessary for movement to occur.1

Specifically, a translational slide typically develops along pre-existing structural features, such as a bedding plane or the interface between resistant bedrock and weaker, overlying material. These planes of parting—the separation between individual rock layers—act as the discrete shear surfaces upon which the overlying mass can slide downward and outward. Because these layers represent natural discontinuities in the rock mass, they often serve as the path of least resistance for gravitational forces, dictating the location and orientation of the slide.12