ENGLISH PAPER

Potentials of Volcanoes

The word volcano comes from the name of the island on the Mediterranean Sea. Mainly the volcanoes are formed by destructive and constructive margins.

A volcano can erupt many times during its lifetime of thousands of years. Material which is expelled during the eruption step by step builds up a volcano. The throat of the volcano is called the main vent; usually there is a crater at the top of the Main Vent. Volcanic eruptions can be described as explosive or quiet. When the magma is sticky and contains lots of gas than eruptions are likely to be explosive. Hot pieces, called pyroclastics are being thrown out during violent explosions. Heavier peaces land near the crater and start to build the cone shaped mountain, lighter peaces can be carried by wind hundred of kilometers away. If the magma is fluid and contains less gas it is when eruptions are quiet. Melted rock called lava runns out of the volcano and cools up on its slope. Non-constant eruptions of pyroclastics materials and lava build the mountain layer by layer. Three different types of materials may be expelled from an active volcano. These materials are lava, rocks (Volcanic bombs, lapilli, cinder, ash, dust) and gases. There are three types of volcanoes: Shield, Cinder and Composite volcano.

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Volcanoes are helpful, too. Can you believe it? The rocks produced from volcanic pressure form most of the ocean floor and continents. Early volcanoes produced steam that later became the water that we cannot live without, as well as the oxygen we need to survive. Volcanic ash and lava also form rich soil, while hot rocks heat underground water. In some countries such as Iceland, it forms hot springs. Engineers are trapping the steam heated by volcanic rock to produce electricity or heat cities.

Although volcanoes are usually linked to death, destruction, and tragedy, they do have some often-overlooked benefits. In New Zealand, people often visit the hot mud baths of Raupehu. More than eight hundred wells exist in Rotorua, a popular spot for those seeking hot water baths, large community swimming pools, natural hot-water tubs, hot-water-heated rooms, and steaming hot springs. The medicinal and health benefits of such relaxing spas are also highly recommended.

Volcanic ash also serves as a natural resource for construction and industry. Lava and tuffs can be cut into blocks and used as stone for buildings. Tuff can be cut into blocks that are used for building. They have enough strength for high buildings, stone walls, are lightweight, resistant to weathering, and good insulators. Fine-grained volcanic ash is used as a polishing compound, and can be found in toothpaste and household scrubbing compounds. Concrete, too, was discovered by Romans who mixed granular volcanic ash with lime cement to create a new, water-resistant material with superior strength. It was this substance that allowed the Romans to build fantastic edifices, water works, aqueducts, roads, harbors, underwater structures, and lighthouses. It is still used in concrete constructions today.

Cinder cones have also been mined as a source of construction materials. Pumice was used by Mediterranean peoples as an exfoliant scrub and abrasive cleaner. Obsidian, a shiny black volcanic glass, has been fashioned into arrowheads and knives, traded, quarried, and even used in eye surgery. Volcanic ash is used as a filler in adhesives, ceramics, bread, and ice-milk products. Volcanic ash is also a major ingredient in cat litter because it easily absorbs moisture.

Volcanoes are also a great tourist attraction. Such monuments as Mount Vesuvius and Mount Fuji are awe-inspiring symbols for their respective nations. Vesuvius was an important destination for artists, writers, poets, and dignitaries. Today, the Hawaiian volcanoes are a great source of tourism.

Geothermal energy is a constant but often under-utilized source of electric power. Environmentally friendly and renewable, this water can be used for growing fish, fruits, and vegetables; drying foodstuffs; and heating residential and commercial buildings. In Iceland, geothermal waters are even piped to homes for bathing and food preparation.

New evidence has also emerged that volcanic areas can be prime petroleum sources. Geothermal systems can also serve an important part in petroleum generation, migration, and entrapment. Many oil-bearing seafloor sediments have been found near hydrothermal vents at midocean ridges. Shell Oil Company also found much oil in volcanic regions in Nevada in 1954, leading to the discovery that volcanic ignimbrites are excellent storage spots for oil pools.

High-energy geothermal systems are also some of the most efficient natural concentrators of valuable ore minerals. Some hot springs in Waiotapu, New Zealand, contain large amounts of gold. At another hot springs, mercury condenses from rising steam at the bathhouses. Many metals, like gold, silver, copper, molybdenum, lead, and zinc have been found beneath such springs.

Volcanoes also bring diamonds up from deep in the earth. Other precious gems, like the red beryl, or "red emerald" is even rarer than a diamond, but can be found in the Wah Wah Mountains in the United States.

Volcanic soils are also some of the richest on earth, providing lush farmland. The best coffees are also grown in volcanic soils in a tropical climate, between elevations of 1,400 and 1,700 meters. These conditions are most commonly found on young, active volcano slopes.

Volcanic rocks are rich in nutrients needed by plants. They are so rich, in fact, that they are considered as "hard" fertilizer. These rich soils encourage farming, agriculture, and population growth.

The constant fall of volcanic ash is also ideal for preserving surface conditions at the time of deposition. Able to bury things intact without moving, crushing, or burning them, volcanic rock is an excellent source for fossils.

Sources :

http://www.sciaga.pl/tekst/34518-35-volcanoes

http://library.thinkquest.org/C003603/english/volcanoes/theadvantages.shtml