The endogenetic processes originate within the earth’s interior and modify the earth’s surface.
The processes are (a) diastrophism and (b) volcanism. Diastrophism includes all crustal movements in the earth. It may either be (i) a slow process with relatively large movements or (ii) fast process with relatively less movement. Orogeny and’ epeirogeny belong to former category while earthquake is a process of later category! Volcanism is the movement of the magma on to the earth’s surface.
The slow and relatively large movements within the earth belong to two types (a) orogeny and (b) epeirogeny.
Progeny means mountain building activities commonly accompanied with deformation almost on a horizontal scale. It deforms the rock strata in form of folds, faults with tilting and displacments. It involves tangential forces with resulting compression or tension of rock strata. Plate tectonism is mainly responsible for orogenic activities. The Himalayas and the Aravallies are formed due to orogenic activities.
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Epeirogeny on the other hand is continent making or regional uplift of the landmass without much horizontal deformation. Commonly, it is acted upon by vertical forces from beneath the earth surface.
Such movements affect the sea – level which is either raised or lowered. The continen individually, have been subjected to great earth movements. Some coas plains are underlain by marine sediments that show that, they were benea the sea in geologic past. Their present position above water indicates a broad regional uplift of the land.