Mass wasting is the downslope movement of soil, rock, and debris driven by gravity. The definition notes vegetation removal and earthquakes as common triggers because they destabilize slopes: removing vegetation reduces root cohesion that helps hold material together, and earthquakes shake the slope, increasing driving stresses and lowering friction along potential failure surfaces. This concept captures the real process of materials moving downslope under gravity, across rapid events like landslides and rockfalls to slower ones like creep. The other terms describe forces inside materials—tension, compression, and shear—not the overall transport of material downslope, so they don’t describe the process as a whole.