The Earth Movements
lithosphere is broken into a number of plates known as the Lithospheric
plates. Each plate, oceanic or continental moves independently over the asthenosphere. The movement of the Earth’s
lithospheric plates is termed as tectonic movements. The energy required to
move these plates is produced by the internal heat of the earth. These plates
move in different directions at different speed.
places, these plates move away from each other creating wide rifts on the
earth’s surface. At some places, these plates come closer and collide. When an
oceanic plate collides with a continental plate, the denser oceanic plate is
forced below the continental plate. As a result of the pressure from above the
rocks heats up and melt. The molten rocks rise again forming volcanic mountains
along the continental edge. Alternatively, a trench may be formed between two
plates. In some cases when two continental plates converge, neither plate can
be forced under the other. Instead, folds may be created. Great mountain ranges
like the Himalayas have been formed in this way.
Asthenosphere - The asthenosphere is the part of the mantle that flows and moves
the plates of the earth.
movement of these plates causes changes on the surface of the earth. The earth
movements are divided on the basis of the forces which cause them. The forces
which act in the interior of the earth are called as Endogenic
forces and the forces that work on the surface of the
earth are called as Exogenic forces.
forces sometimes produce sudden movements and at the other times produce slow
movements. Sudden movements like earthquakes and volcanoes cause mass
destruction over the surface of the earth.