Geomorphology is the scientific study of the surface of a planet and those processes responsible for forming it. Scientists involved in this field often study historical changes, through events such as erosion, in order to understand how a particular geographical region came into existence. They may also study current data to better predict how landforms might change in the future and to understand how people can help maintain current features. This allows scientists to anticipate changes in the general structure of the earth.
Natural Processes of Change
Landforms on any world, including earth, are not static; they are part of a dynamically changing system. There are various geomorphic processes that can alter the surface of a world, including plate tectonics, changes in climate, and human activities. Wind can shape landscapes, as can water — both liquid and ice, in the form of glaciers. Volcanic activity, including violent eruptions and the steady flow of lava from some sites, can create new islands or devastate a landscape. Plants and animals can also alter landforms, whether a beaver damming a river or a grove of trees that anchor the soil in a particular location.
Tectonic Changes
Slow movements of the earth's tectonic plates contribute to the uplift and elevation of landforms. There are two common types of tectonic uplift: orogenic and isostatic. Orogenic tectonic uplift is caused when tectonic plates crash together, which raises the land where they meet to create forms such as mountains. Isostatic uplift, on the other hand, refers to how landforms can become higher after the weight on the land is reduced; as land is eroded or glaciers melt, it is believed that the land that was being weighed down can rise.
Changes Caused by Water
The geomorphic effect of water bodies are studied in fluvial geomorphology, which examines how bodies of water alter the landscape. As waterways such as rivers flow, they often carry sediment, which reduces the land around the river itself but increases areas where this sediment is released. Water from rain and flash floods can also be responsible for erosion, which physically alters rocks and other land areas.
Changes Caused by Glaciers
Glaciers also change the landscape. As these heavy sheets of ice advanced across the landscape during the last ice age, they scoured the softer land areas in their way; they also picked up some of this material and moved it. When the ice melted, valleys and fjords — coastal valleys that are filled with water — were left behind, as were the rocks and soil, called "till," that the glacier picked up.
Volcanic Changes
On the opposite side, volcanoes can both create and destroy landforms. Often found at the edges of tectonic plates, underwater volcanoes have shaped islands like Hawaii, the Philippine Islands, and New Zealand. On land, they can form large volcanic mountains. The violent explosion of a volcano can radically change the landscape, and wipe out plants and animals in the area.
Changes Caused by Wind
Although it often works much more slowly, wind can also alter the land. Called eolian geomorphology, wind can erode landforms, breaking them down, and build others up, as material is moved from one place to another. The Nebraska Sand Hills, for example, is an area where ancient winds created huge sand dunes that have since stabilized and became a regular part of the landscape.
Biogeomorphology
Plants and animals can have a big impact on the landscape as well. Animals dig tunnels and dens, move rocks and soil, and block rivers, among other things. Plant roots can grow through the cracks in rocks, breaking them apart, or help to hold the soil in an area together, decreasing erosion caused by water and wind. Living things can also combine with other forces to cause changes; a volcanic eruption may destroy a stand of trees, for example, leaving the land in the area exposed to the weathering caused by wind and rain.
Changes Caused by People
Human interventions can also contribute to changes on the earth. With the expansion of civilization, humans began to enact direct changes to their surroundings. The most radical changes to landforms are possible due to technological and organizational advances; the building of the Panama or Suez canals, for example, were significant alterations to the earth's natural form. People have straightened rivers or prevented them from naturally changing their course, created lakes and other bodies of water, and prevented beaches from expanding or eroding in some cases. The long-term effects of many of the changes that human beings have made is not fully known, and it may take centuries for the side effects — good and bad — to become fully clear.
Geomorphology on Other Planets
Geomorphology is not restricted to questions about landforms on earth; it applies to all terrestrial planets. The field of "extraterrestrial geomorphology" is expanding due to the influx of scientific data from satellites and space expeditions. For example, volcanic eruptions on the surface of Io, one of Jupiter's moons, have created many unique features, including tall mountains and flat plains. Scientists studying Mars, Venus, and other planets examine formations like channels and valleys, and theorize about the different processes that might have created them.
Related Fields of Study
A number of different research methods and fields of inquiry are often used for this type of study. Archaeology, for example, can be invaluable in understanding how past human populations have changed and shaped the environment and geography. Study of global surveys through ground and orbital photography is also beneficial, as it allows geomorphologists to gain a better perspective of various landforms. Soil scientists investigate the composition and formation of soils, which helps explain how an area has changed over time.
Geomorphology is also used in a number of other fields. Civil engineers, for example, build and maintain structures like roads, bridges, and dams; understanding how the landscape was formed and how it may change is crucial for such projects. Environmental resource management involves finding ways to make the best use of resources, including water and land, so an understanding of how human activities can change those resources is vital.