Volcanoes are mountains that are made of materials thrown up through vents from the interior of the earth. A volcano has a surface opening connected to the vent – this opening is called crater while volcanism is the movement of magma as it rises up to the surface of the earth.
Formation of Volcano
Scientific explanations say earth’s interior is very hot and the magma in it is very solid, this is because of the great pressure above it. When pressure is lessened because of the formation of faults in the rocks, the magma then becomes liquid and it would flow toward areas where pressure is low. When it reaches the surface, volcanic eruption happens. Lava, fragments of solid, ashes, and smoke comes out a hole in the ground. As eruptions continuously repeated, more materials are deposited in the surrounding place near the hole. In due time, this pile of materials grows to a certain height, thus offspring is a volcano.
On February 20, 1943 in Paricutin, Mexico, one farmer named Dionisio Palido while plowing his cornfield, he noticed a familiar hole became wider. In the same afternoon he saw this hole raised itself from the ground to a height of about two meters. A smoke with hissing sound came out of it with a smell of sulfur. Later, ashes and red hot stones were thrown into the air, and by midnight, glowing rocks were thrown into the sky from the hole. This is how a volcano was born in this area in Mexico and it was nine months after when it was already about 2,771 meters high when it mellowed down.
What Comes Out of It
During a volcanic eruption, the smoke that comes out of the volcano is actually a mixture of gases but most of it is water vapor. Other gases include carbon dioxide, carbon monoxide, sulfur oxide, ammonium chloride and methane. Also, during eruption, solid particles like lava, ashes, rocks and other dash particles are thrown out and eventually they pile up along the slope of the volcano. When it rains, these materials are carried down in streams of mudflow commonly called lahar.
Types of Volcanoes
Volcanoes are classified as either inactive or active. An active volcano is one which has erupted within historic times while the inactive is the one otherwise. One good example of active volcanoes can be found in the Philippines, a country in Asia where the whole archipelago has more than 200 volcanoes. They have 22 volcanoes and five of these are considered very active. They are Mt. Bulusan in Sorsogon, with 17 eruptions; Mt. Canlaon in Negros, with 15 eruptions; Mt. Hibok-Hibok in Camiguin, with19 eruptions; Mt. Mayon in Albay, with 43 eruptions; and Mt. Taal in Batangas, with 32 eruptions.
The Effects of Volcanic Eruptions
Aside from its harmful effects in the environment, death of mankind is the large scale effect. When Taal Volcano in the Philippines erupted in 1911, it claimed more than 1,300 people. While Mt. Krakatoa in Indonesia claimed about 36,000 lives as a result of seismic waves generated by the eruption, in fact this is regarded as the most devastating in history. Volcanic eruption also results in the destruction of agricultural lands and its crops and animals like what happened in the eruption of Mt. Pinatubo in the Philippines, it buried crops in the fields and live animals.
Lahar from Mt. Pinatubo destroyed bridges, roads, houses, and even buildings and this displaced people from their work and homes. The Taal Volcano is considered one of the most active volcanoes in the world for it erupts almost every ten years.
Beneficial Effects of Active Volcanoes
The ashes from volcanoes are rich in silica which fertilizes soil, and good soil produces better quality of crops. If ground water is deep then it may be heated by magma thus gives hot water spring. A hot spring is formed when the rainwater seep into the ground and heated by the hot rocks.
The magma near volcanic areas is also a source of heat energy called geothermal energy which can be used in heating, cooking, bathing, or even drying. This geothermal energy is produced when groundwater gets in contact with the hot rocks below the volcano thus produces electricity as its most important value.
Some volcanic materials may also be used to construct homes, build bridges, and roads. Artistic people used these to create decorative figurines.
Now this may be a revelation but the truth is – volcanoes are considered the earth’s safety valves. Isn’t it that a tremendous pressure builds up beneath the surface of the earth, volcanic eruptions release this great pressure caused by the rocks or plates being dragged into the mantle.
Can Volcanic Eruptions be Predicted like that of Weather
To some extents, volcanic eruptions may be predicted. Some signs like increased tremors near the volcano; increase of temperature of surface, swelling of the ground, though volcanic eruptions cannot really be predicted accurately.