Concept:Mass movement refers to the downward movement of surface materials like rocks, soil, or mud under gravity.
Explanation:Mass movement processes include landslide, rockslide, and talus creep.
These all involve the gradual or sudden downslope flow or slide of earth materials.
An earthquake is a sudden shaking of the ground caused by tectonic forces, not a form of mass movement itself.
It can trigger mass movements, but it is not classified as one.
Therefore, the option that is not a form of mass movement is earthquake.
Answer:B. earthquake