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VOLCANOES

VOLCANO

•Volcano is a vent or opening in the earth’s crust from which magma or molten rock materials emerges out.

STRUCTURE OF A VOLCANO

• Magma:

Molten rock materials found within the earth’s interior

• Lava:

When the magma reaches the earth’s surface it loses water vapour, some gases , ash, dust etc. and then it is called Lava.

• Fissure:

Through which the magma comes out • Vent:

The magma comes out from the aesthenosphere on to the crust of the earth is known as Vent.

• Crater:

The Funnel shaped depression that can be seen on the summit of a volcanoe.

Volcanic mountain:

The rocks and other materials which come on to the surface of the earth from the interior of the earth accumulates to develop volcanic mountains.

World Map of Volcanoes

TYPES OF VOLCANOES

Volcanoes

Active Dormant Extinct

• Active Volcanoe:

Those that frequently errupt Eg: Mt. Etna (Italy), Mt. Fujiyama (Japan)

Mt. Etna which recently errupted in December 2013

• Dormant volcanoe• Those that have errupted earlier and not

active in the recent past, but can become active.

Eg: Mt. Vesuvius (Italy)

Mt, vesuvius lastly erupted in 1944

• Extinct volcanoe• Active at a time but will not errupt again Eg: Mt. Kilimanjaro (Africa)

The last major eruption has been dated to between 150,000 and 200,000 years ago

PACIFIC RING OF FIRE