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 Form 2 Geography Online Lessons on Internal Land Forming Processes

In this lesson we are going to discuss the Definition of land forming process, the Earth Movements i.e Horizontal and Vertical and their Effects and results

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Answer Text:
Internal Land Forming/endogenic Processes
-Processes operating in the interior of the earth resulting in the formation of natural physical features or landforms.
-They are caused by earth movements.
-Examples of these processes are folding, faulting and vulcanicity.
Formation of land forms by internal land forming processes is determined by:
• Nature and age of earth materials
• Type of movement involved
• Intensity and scale of movement involved
Crustal Earth Movements
- Displacement of the earth’s crustal rocks.
-They are brought about by tectonic forces which originate and operate in the interior of the earth e.g. tensional forces (which operate along horizontal plane moving away from each other), compressional forces (which operate along horizontal plane moving towards each other), shear forces (which move past each other with unequal strength) and gravitational forces (which attracts things to the earths centre).
Earth movements are of 2 types:
1. Horizontal/lateral/orogenic movements
2. Vertical/epeirogenic movements
Horizontal Earth Movements
- Movements which act along a horizontal plane within crustal rocks.
They are caused by tensional and compressional and shear forces.
They cause:
• Strain and stretching of crustal rocks due to stretching caused by tensional forces which cause formation of cracks or faults.
• Squeezing and shortening of crustal by compressional forces rocks which cause them which also cause formation of faults.
• Crustal rocks to shear by slipping past each other or by dividing into layers which is caused by shear forces.
Results of Horizontal Earth Movements
- Results in the formation of the following features:
1. Faults
2. Rift valleys
3. Fold mountains
4. Escarpments
5. Basins
6. Tilt blocks
7. Block mountains
Vertical Earth Movements
-Movements which occur along the earth’s radius or towards the earth’s surface or towards its centre.
• Subsiding/sinking/down warping or pulling of crustal rocks downwards.
• Uplifting/up warping or pushing of crustal rocks upwards
• Tilting of crustal rocks or shearing in vertical direction due to greater uplift on one side.
Results of Vertical Earth Movements
1. Raised cliffs
2. Tilt blocks
3. Rift valleys
4. Fault scarps/escarpments
5. Plateaus
6. Basins