Both earthquakes and volcanoes are the results of the instability of this zone. There are different forces that erode the earth's landforms. Weathering, which is one of them, causes the physical disintegration and chemical decomposition of earth materials at or near the earth's surface. There are different types of weathering, these being mechanical, physical, and chemical. Water is a mechanical weathering force.
Evidence shows that water molds the earth's surface through rivers and ocean waves.
One of the largest examples of water as a weathering force is the Grand Canyon. The Colorado River has molded and shaped this canyon over the last 5 million years. Physical weathering breaks rocks into pieces. Animals, insects, worms, and burrowing mammals all work to loosen the soil by aeration and by mixing loose materials. Another main cause of physical weathering is the ice formations in rocks.