Meaning of Volcano

A volcano is a landform, an opening in the earth’s crust.

This opening is connected with a magma chamber under the surface of the earth.

A magma chamber is a storage full with magma or molten rocks.

It allows hot molten rocks, ash and gases to escape from below the earth’s surface.

The molten rocks or magma comes out from the magma chamber through a vent in the form of lava.

The vent is located in the middle of a volcanic mountain.

With time, the lava and ash cools down and solidify in layers in the earth’s surface forms a volcano.

The shape or form of a volcano varies according to the material ejected.

It is usually in a form of a cone.

It also can be in a form of a dome.

Let’s discuss the types of volcanoes.

There are three types of volcanoes i. Active volcanoes ii. Dormant volcanoes iii. Extinct volcanoes

Active volcanoes

These are the volcanoes which are presently in active state.

These are constantly ejecting lava, gases, ashes etc.

There are1500 known active volcanoes among which 50 or so erupt every year.

There are several hundred volcanoes in the world and most of them are in the Pacific Ocean and Atlantic islands.

Some of the examples of active volcanoes are: Mt. St. Helens in USA

Stromboli and Etna in Mediterranean sea.

The Stromboli volcano emits so much fire that it comes to known as Light House of Mediterranean sea.

Pinatubo in Philippines.

Dormant volcanoes

These are the volcanoes which have not erupted in recent historical period.

These are also known as ‘sleeping volcanoes’ and may become active in any time.

The best example of dormant volcano is Mt. Vesuvius.

It erupted first in 79 AD and remained dormant for over 1500 years. Again it erupted in 1631 AD and in different times from 1803-1929.

Another example of dormant volcano is Mt. Kilimanjaro of Africa.

Extinct volcanoes

These are the volcanoes which have not erupted in the present geological period and are not likely to become active again.

The crater of an extinct volcano filled up with water and forms a lake known as Crater Lake.

Examples of extinct volcanoes are: Mt. Aconcagua in South America

Mt. Kenya in Africa

Revision

A volcano is an opening in the earth's crust which is connected to a magma chamber from which molten lava, ashes and gases are ejected.

A volcano is usually in the form of a cone or dome according to the material ejected.

There are three types of volcanoes i. Active volcanoes ii. Dormant volcanoes iii. Extinct volcanoes

Active volcanoes are the volcanoes which are presently in active state. These are constantly ejected lava, gases, ashes etc. Eg. Mt. St. Helens, Stromboli etc.

Dormant volcanoes are the volcanoes which have not erupted in recent historical period and known as sleeping volcanoes. Eg. Mt. Vesuvius.

Extinct volcanoes are the types which have not erupted in the present geological period and are not likely to become active again. Eg. Mt. Kenya

The End