I'm not sure if this is right, but i believe the right answer would be fracture.
Explanation:
In geology, a fracture is any separation in a geologic formation, such as a joint or a fault that divides the rock into two or more pieces. A fracture will sometimes form a deep fissure or crevice in the rock. Fractures are commonly caused by stress exceeding the rock strength, causing the rock to lose cohesion along its weakest plane.
Mountain slopes have faster erosion because it is easier for fast moving bodies of water to carry down eroded material downhill, rather than across flat land.
