Answer in brief

Social Science : Geography

LITHOSHERE – I

ENDOGENETIC PROCESSES

IV. Answer in brief.

1. Write a brief note on the various spheres of the Earth.

Various spheres of the Earth:

• The Lithosphere is the solid outer part of the Earth.

• The Hydrosphere is the watery part of the Earth's surface including oceans, rivers, lakes and water vapour.

• The Atomsphere is a thin layer of gases that surrounds the earth.

• The Biosphere is the layer of Earth where life exists.

2. Mention the layers of the interior of the Earth.

The layers of the Interior of the Earth.

• The crust

• The mantle

• The core

3. Define plate tectonics :

Tectonic Plates:

• Tectonic plates in Lithosphere are divided into major and minor plates. These plates float over the mantle.

• The movement of tectonic plates is due to thermal energy from the mantle. Collisions of these plates produce mountain ranges and irregular surfaces.

4. What is Tsunami?

• Large seismically generated sea waves caused by Earthquakes, submarine explosions and land slides are 'Tsunami'. (Tsunami - a Japanese term for harbour waves)

• Tsunami travels at more than 500 km / hour. The length 600 km and the height 15 m.

5. What is a volcano? Mention its major components.

Volcano:

• Magma ( hot solid, liquid and gaseous materials), in the Earth's interior erupt out to the surface of the Earth crust through an opening is a 'volcano'.

The compoments of Volcanols

• Magma chambar

• Vents

• Volcanic cone

• crater.

6. What is an Earthquake and how it occurs?

Earthquake:

• Earthquakes are generally caused by the sudden vibrations in the Earth's crust.

• The point of origin of an Earthquake is 'Focus' (Hypocenter).

• 'Epicentre' is a point on Earth's surface that lies directly above the focus.

7. What are seismic waves and Mention its types?

Seismic Waves:

• Earthquakes generates 'seismic waves'. The nature, force and speed of these waves depend on the nature of the medium through which it passes.

Types of waves:

• Primary or ('P' waves)

• Secondary waves ('S' - waves)

• Surface waves ('L' - waves)

8. Write about the Pacific Ring of fire.

• The Pacific Ring of fire is the pacific plate meets many surrounding plates.

• The Ring of fire is the most seismically and volcanically active zone in the world.