Introduction to Earth's Spheres
The Earth consists of four interconnected spheres:
Lithosphere: The solid crust and upper mantle of the Earth.
Atmosphere: The blanket of gases surrounding the Earth.
Hydrosphere: All water bodies on the Earth's surface.
Biosphere: The zone where life exists.
Internal / Endogenetic Forces
Endogenetic forces are pressures that originate deep inside the Earth. These forces create major landforms like mountains, valleys, and plateaus through two main actions:
A. Plate Tectonics
The lithosphere is broken into large slabs called Tectonic Plates. These plates move constantly due to internal heat energy, creating three types of boundaries:
1.Convergent Boundary: Plates collide against each other (Forms Fold Mountains like the Himalayas).
2.Divergent Boundary: Plates pull apart from each other (Forms Rift Valleys).
3.Transform Boundary: Plates slide past each other horizontally (Causes Faults).
B. Earthquakes
An earthquake is a sudden shaking of the Earth's crust caused by the release of energy along a fault plane.
Focus (Hypocentre): The exact point inside the earth where the earthquake originates.
Epicentre: The point on the Earth’s surface directly above the focus (where damage is highest).
Measurement: Measured using a Seismograph and quantified on the Richter Scale.
C. Volcanoes
A volcano is a vent or opening in the Earth’s crust through which molten rock (Magma inside, Lava outside), gases, and ash erupt.
Active Volcano: Erupts frequently (e.g., Mt. St. Helens, Barren Island in India).
Dormant Volcano: Has not erupted for a long time but can erupt anytime (e.g., Mt. Fuji).
Extinct Volcano: Has completely stopped erupting permanently (e.g., Mt. Kilimanjaro).
Conclusion
Endogenetic processes are the primary builders of Earth's topography. Without these internal forces pushing the crust upward, surface forces (like wind and water) would have leveled the entire planet down to sea level over time.
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