PPT: Volcanism | Crash Course for UPSC Aspirants PDF Download

 Page 1


Geography 
Crash Course
Page 2


Geography 
Crash Course
Volcanoes
• The word volcano is derived from the name of 
‘Vulcano’, a volcanic island in the Aeolian 
Islands of Italy whose name in turn originates 
from ‘Vulcan’, the name of a god of fire in 
Roman mythology.
• Volcano is a vent or an opening through which 
heated materials consisting of water, gases, 
liquid lava and rock fragments are erupted 
from the highly heated interior to the surface of 
the Earth. The layer below the solid crust of 
earth is mantle.
Page 3


Geography 
Crash Course
Volcanoes
• The word volcano is derived from the name of 
‘Vulcano’, a volcanic island in the Aeolian 
Islands of Italy whose name in turn originates 
from ‘Vulcan’, the name of a god of fire in 
Roman mythology.
• Volcano is a vent or an opening through which 
heated materials consisting of water, gases, 
liquid lava and rock fragments are erupted 
from the highly heated interior to the surface of 
the Earth. The layer below the solid crust of 
earth is mantle.
Vulcanicity
• Vulcanicity includes all those processes in 
which molten rock material or magma 
rises to the crust to solidify as crystalline 
or semi-crystalline rocks. Some scientists 
use ‘vulcanism’ as a synonym for 
vulcanicity.
Page 4


Geography 
Crash Course
Volcanoes
• The word volcano is derived from the name of 
‘Vulcano’, a volcanic island in the Aeolian 
Islands of Italy whose name in turn originates 
from ‘Vulcan’, the name of a god of fire in 
Roman mythology.
• Volcano is a vent or an opening through which 
heated materials consisting of water, gases, 
liquid lava and rock fragments are erupted 
from the highly heated interior to the surface of 
the Earth. The layer below the solid crust of 
earth is mantle.
Vulcanicity
• Vulcanicity includes all those processes in 
which molten rock material or magma 
rises to the crust to solidify as crystalline 
or semi-crystalline rocks. Some scientists 
use ‘vulcanism’ as a synonym for 
vulcanicity.
Causes of Vulcanism
• Magma is formed due to the lowering of melting point, 
which in turn is caused by the reduction in pressure of the 
overlying material.
• Gases and vapour are formed due to heating of water, which 
reaches underground through percolation.
• The ascent of magma forced by vast volume of gases and 
water vapour.
• The occurrence of volcanic eruption.
Page 5


Geography 
Crash Course
Volcanoes
• The word volcano is derived from the name of 
‘Vulcano’, a volcanic island in the Aeolian 
Islands of Italy whose name in turn originates 
from ‘Vulcan’, the name of a god of fire in 
Roman mythology.
• Volcano is a vent or an opening through which 
heated materials consisting of water, gases, 
liquid lava and rock fragments are erupted 
from the highly heated interior to the surface of 
the Earth. The layer below the solid crust of 
earth is mantle.
Vulcanicity
• Vulcanicity includes all those processes in 
which molten rock material or magma 
rises to the crust to solidify as crystalline 
or semi-crystalline rocks. Some scientists 
use ‘vulcanism’ as a synonym for 
vulcanicity.
Causes of Vulcanism
• Magma is formed due to the lowering of melting point, 
which in turn is caused by the reduction in pressure of the 
overlying material.
• Gases and vapour are formed due to heating of water, which 
reaches underground through percolation.
• The ascent of magma forced by vast volume of gases and 
water vapour.
• The occurrence of volcanic eruption.