In the context of slope movement, what is characterized as "debris"?

The term "debris" in the context of slope movement commonly refers to an accumulation of loose material that is mixed, typically consisting of a variety of particle sizes and types. This often includes a significant amount of coarse soil, which encompasses gravel and larger aggregate materials. Debris can result from natural processes such as weathering, erosion, and mass wasting events like landslides.

When discussing slope instability, the presence of coarse materials is critical because they can influence the dynamics of movement—a debris flow, for example, involves saturated soil and large rock fragments that flow down a slope with great force. This mix of coarse components acts as an effective transportation medium for finer materials, thus characterizing slope failures commonly referred to as "debris flows."

In contrast, bedrock is less relevant in this context as it does not represent loose material that can flow or slide. Mostly fine soils are less indicative of debris movement since they tend to behave differently under shear stress than coarse materials. Similarly, the term "loose material" is broad and could refer to both fine and coarse textures, but it is the coarse components that specifically dominate the characterization of "debris" in slope movements. Therefore, the choice emphasizing mostly coarse soils correctly identifies a key aspect of what