FORCES AFFECTING THE CRUST OF THE EARTH
There are various forces which change or alter the surface of the Earth. These forces create, destruct, recreate landforms on the Earth and maintain the geo-materials on the earth’s crust.
All the forces that can cause change in landforms are categorise into two;
- ENDOGENIC FORCES (INTERNAL FORCES)
- These forces change or alter landforms inside the earth. This energy is mostly generated by radioactivity, rotational and tidal friction and primordial heat from the origin of the earth.
- the action of endogenic forces are not uniform and its resulted surface is uneven because of
- the variations in geothermal gradients and heat flow inside the Earth,
- crustal thickness and strength,
- Endogenic Forces are again divided into sudden forces and Diastrophic Forces.
- Volcanic activities and earthquakes are categorised into sudden forces because they can alter landforms in very short time.
- Diastrophic Forces forces modify landforms very slow. Even we cannot experience it with it in our whole life.
- Diastrophic Forces: Diastrophic Forces move, elevate or build portions of the earth’s crust. It is of two types:
- Epirogenetic Force: these forces work vertically. it causes upheavals or depressions in land. due to these forces mountains, valleys, plateaus are formed
- Orogenetic Force: these forces cause horizontal movement in crust. Land can come close or break apart. Due to these forces faults, block mountains etc are formed.
- EXOGENIC FORCES (EXTERNAL FORCES)
- These are forces that work over the surface to modify the landforms. It include processes like weathering, erosion, deposition etc.
- They are also called denudational or destructional forces.