VOLCANOES

                  In 1943, A farmer in Central Mexico was ploughing his cornfield when his son came running towards him. He had heard a growling sound coming from the ground nearby. When the farmer went to the spot, he saw a cloud of smoke. He ran to fetch his wife and his neighbours and when they reached the field, they found an opening in the ground. In the days that followed, they heard loud explosions and saw chunks of rock bursting high into the air out of this opening and then a boiling hot liquid began oozing from it.
                  In four months, at the spot where the smoke was seen, there stood a mountain about one thousand feet high. What the farmer had seen was a volcano in action. The story of any volcano, however, begins several kilometres under the ground. The deeper you go into the earth, the hotter it becomes; hot enough to melt even rocks! This molten rock is called Magma. Sometimes this hot, boiling Magma forces its way out through the earth's surface. If the magma comes out with great force, there will be an explosion and solid lumps of rock will be blown out as it happened in Mexico.
                 The opening on the earth's surface through which the magma comes out, is called a volcano. The Magma that has come out, is called Lava. This Lava which flows out of the volcano hardens into solid rock when it cools. As the Lava oozes out, some of it plies up around the opening. If the volcano keeps erupting, more and more Lava piles up and in course of time, you could have a cone-shaped volcanic mountain standing on the spot.
                 One such volcanic mountain is Fujiyama in Japan. There are several thousand volcanoes on the surface of the earth but most of them have not erupted for hundreds of years. Sometimes the Lava flows out of a number of cracks in the earth and the lava spreads over the land in thick layers. The Deccan Plateau has been formed in just this way. The plateau contains 520,000 kilometres of Lava which flowed out millions of years ago.


A Volcano
                 

0 comments:

Post a Comment