Both earthquakes and Volcanoes are the results of the instability of this zone. As we already know tectonic forces, plate tectonics, earthquakes, and volcanoes roughen the earth's surfaces. There are different forces that erode the earth's landforms. Weathering is a physical disintegration and chemical decomposition of earth materials at or near the earth's surface. 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 the 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. Even a human taking a hammer and smashing something to pieces is an example.