Cliffs are steep formations of rock that occur frequently in nature along coasts, riverbeds and in mountainous regions. Cliffs can be formed by several different natural phenomena, though often the formation of cliffs involved tectonic activity. Underneath the ground, the earth consists of large tectonic plates that shift around over time. When two of these plates meet, extreme pressure is created which sometimes forces one or both of the plates upwards over time. This can result in the creation of mountains and cliffs. The most violent episodes of tectonic activity can result in earthquakes, which can create tears in the earth and form cliffs.
Water and Erosion
Another common way cliffs are formed is through the action of water and weathering, which erodes rock over time. Especially common in cliffs occurring along coasts or large lakes, the repeated lapping of water against rocks as waves gradually wears the rock down, which can form cliffs over many thousands of years. In other cases, rivers and gullies that swell with rain water gradually cut into the earth as they flow, which can create cliff walls on either side of the moving water, such as the Grand Canyon.
Another cause of the formation of cliffs were the glaciers that once covered much of the earth during the ice age. When the glaciers slowly moved across the earth, their tremendous weight ground out depressions in certain areas creating cliffs much like a river would. The difference is that glaciers are extremely expansive so the cliffs they form can cover large areas instead of being confined to a certain, path like a river. As a result, large regions that used to be covered in glacier tend to be scattered with sheer rock outcroppings.