Erosion is wear on a solid surface
Erosion occurs mainly through the operation of wind, running water or ice. Also erosion is possible by volcanism or (meteorite) impacts. It is a natural phenomenon that can be reinforced by human action. By cutting trees or keeping the soil bald, soil erosion can accelerate. When the trees are cut down on a mountainside, rainfall can flow down the water more quickly and rinse more ground: abrasion of the mountain.
Erosion: [YouTube] nQAdnCiugH4 [/youtube]