Volcanoes come under the category of natural calamities. Man has no control over them. He can at best predict their occurrence and that too not exactly. Volcanoes, when they erupt, destroy life and property on a large scale.
We know that the sun is a burning star and the planet earth is a part of it. When the earth got separated from the sun it was also burning. Gradually it cooled down on the surface. But internally it is still a burning inferno. In the deep parts of earth, moulted rocks and gases want to burst out from the crystal rock base upwards. They find ways called vents which are zigging holes. They travel up to the surface with their great force and burst out through openings called craters, which are like wide open mouths for them.
Volcanoes spread out solid matter, liquid matter, as well as gases. The solid matter thrown out consists of broken pieces of blasted rocks. The molten material shoots out very high into the sky. Bu the time it comes down it cools and becomes solid. These solid pieces are called cinders. The liquid matter that is ejected out by the volcanoes is called Magna. As soon as it comes out of the volcano it is called lava. Its temperature is very high. It appears red and white when it is hot and turns black after it cools. The lava destroys by burning everything that comes in its way when it flows and when it cools it covers everything under it. They city of Prompey is a good example for lava flow. Then there is the third one, gaseous material. Steam is the major part of the material gas; water mixed with Magna is also ejected along with the steam. This water is called Juvenile Water.
In the world there are 500 volcanoes which are either active or have been active in historical times. Volcanoes appear to have some closer connection with mountain areas and weaker surfaces of the earth.
The areas where volcanoes are to be seen are divided into select areas.
1. Island Fastoons of the Pacific:
Two third of the world’s active volcanoes and thousands of inactive volcanoes could be seen in this area. This area is also called the Circle of Fire. Among the noted volcanic areas in this belt, are Aleutian Islands, Alaskan sub-continent. Goutemala, Southern Andes and the circle takes a round to occur at two places on the Atlantic side.
2. Alpine Himalayan belt:
The Vesuvius and the Again volcanoes are in this belt. After touching the Himalayas the belt passes through Myanmar, Andaman’s and extends right up to Indonesia.
3. African Rift Valley:
It starts from the Bay and passes through Africa right up to the Red Sea. In this volcanoes belt, we find Camaroon Mt. Kilimayaro and Kenyan Volcano mountains. There are other volcanic belts which are smaller. Some of them are in Mid-Atlantic. Cape Verde is famous among them.
Some volcanoes when they are active burst out every 20 or 30 minutes. Some of them may be dormant now and become active later. The number of active volcanoes is about 300 in the world now.
The Barren Island of the Andaman group of islands in our country and Etna in the Island of Sicily are examples of active volcanoes. Mt Enma has erupted several times during recent years. A dormant volcano is like a sleeping volcano. It may erupt at any time. The Vesuvius near Neples in Italy is said to be a dormant volcano. Volcanoes which have not erupted for thousand of yeas are called extinct volcanoes. The Mt. Kilimanjaro in Tanzania comes under this category.