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The volcano is named after Vulcano, an Italian island north of Sicily. Map of Sicily. The Vulcano has been active for thousands of years and the ancient Romans named their god of fire, Vulcan, after it. Hephaestus (Vulcan). When Zeus (the most powerful god) discovered that man possessed fire, he was terribly angry. He commanded Hephaestus to make a set of chains. Hephaestus was a god of many skills, often referred to as the Blacksmith of the Gods. With these chains, Zeus had Prometheus (the god who brought fire to the humans) tied to a great rock and left him to be tormented by a cruel eagle. The Romans believed that the smoke and fire rising from the volcano came from his forge where he and his assistants the Cyclops were at work in his smithy below. Hence they named the volcano after him. Structure of a Volcano A volcano constitutes a vent, a pipe, a crater, and a cone. The vent is an opening at the Earth's surface. The pipe is a passageway in the volcano in which the magma rises through to the surface during an eruption. The crater is a bowl-shaped depression at the top of the volcano where volcanic materials like, ash, lava, and other pyroclastic materials are released. Solidified lava, ashes, and cinder form the cone. Layers of lava, alternate with layers of ash to build the steep sided cone higher and higher. Volcanologists have classified volcanoes into groups based on the shape of the volcano, the materials they are built of, and the way the volcano erupts. The groups are: •Composite Volcanoes (also called strato volcanoes), •Shield Volcanoes (also called shields), •Cinder Cones, •Spatter Cones, and •Complex Volcanoes (also called compound volcanoes). Shield Volcano Shield volcanoes are huge in size. They are built by many layers of runny lava flows. Lava spills out of a central vent or group of vents. A broad shaped, gently sloping cone is formed. This is caused by the very fluid, basaltic lava which can't be piled up into steep mounds. Shield volcanoes may be produced by hot spots which lay far away from the edges of tectonic plates. Shields also occur along the midoceanic ridge, where sea-floor spreading is in progress and along subduction related volcanic arcs. The eruptions of shield volcanoes are characterized by lowexplosivity lava-fountaining that forms cinder cones and spatter cones at the vent. Famous shield volcanoes can be found for example in Hawaii (e.g. Mauna Loa and Kilauea). Composite Volcano Composite volcanoes, also called strato volcanoes, are formed by alternating layers of lava and rock fragments. This is the reason they are called composite. Strato-volcanoes often form impressive, snow-capped peaks which are often exceeding 2500m in height, 1000sq.km in surface, and 400 cubic kilometers in volume. Between eruptions they are often so quiet they seem extinct. To witness the start of a great eruption requires luck or very careful surveillance. Different Shapes of Composite Volcanoes. Strato-volcanoes are constructed along subduction zones. Examples of composite volcanoes include Mount Hood, Mount Rainier, Mount Shasta, Mount Fugi, Mount Mayon, and Vesuvius. Composite volcanoes usually erupt in an explosive way. This is usually caused by viscous magma. When very viscous magma rises to the surface, it usually clogs the crater pipe, and gas in the crater pipe gets locked up. Therefore, the pressure will increase resulting in an explosive eruption. Although strato-volcanoes are usually large and conical, we can distinguish different shapes of them: concave (like Agua), pyramidal (like Stromboli), convex-concave (like Vesuvius), helmet-shaped (like Mount Rainier), collapse caldera (like Graciosa), nested (like El Piton in Teide), multiple summits (like Shasta), elongated along a fissure (like Hekla). Different Shapes of Composite Volcanoes. A cinder cone is a steep conical hill formed above a vent. Cinder cones are among the most common volcanic landforms found in the world. They aren't famous as their eruptions usually don't cause any loss of life. Cinder cones are chiefly formed by Strombolian eruptions. The cones usually grow up in groups and they often occur on the flanks of strato volcanoes and shield volcanoes. Cinder cones are built from lava fragments called cinders. The lava fragments are ejected from a single vent and accumulate around the vent when they fall back to earth. Cinder cones grow rapidly and soon approach their maximum size. They rarely exceed 250m in height and 500m in diameter. The shape of a cinder cone can be modified during its (short) life. When the position of the vent alters, aligned, twin or secant cones develop. Nested, buried or breached cones are formed when the power of the eruption varies. A great example of a cinder cone is Paricutín in Mexico. It was born in February 20, 1943 in a corn field and grew to 300 feet in 5 days. Spatter Cone When hot erupting lava contains just enough explosive gas to prevent the formation of a lava flow, but not enough to shatter it into small fragments the lava is torn by expanding gases into fluid hot clots, ranging in size from 1cm to 50cm across, called spatter. When the spatter falls back to Earth the clots weld themselves together and solidify forming steep-sided accumulations. These accumulations focused on an individual vent are called spatter cones. In fact all volcanoes could be complex volcanoes since all of them are made up of multiple flows, ash layers, domes, cones, etc. in varying amounts. However, when we call a volcano a complex volcano it is because we mean the "system" of those volcanoes is not "simple". Caldera complexes for instance have often got a large caldera with many subsidiary vents and deposits, some of which could be considered "volcanoes" in their own right. Frankly speaking, a volcano that consists of a complex of two or more vents is reckoned as a compound or complex volcano. Besides Volcanoes, some other features may be found in volcanic areas as well. These include: •Calderas and Crater Lakes, •Volcanic Plugs, •Lava Plateaus, •Geysers and Hot Springs Caldera of Tengger in Java, Indonesia. Calderas are huge bowl-shaped craters, usually formed by volcanic activity. Some of the earliest geologists thought the calderas are formed when violent volcanic eruptions blew the tops off the volcano. However, few calderas are formed this way. Calderas are formed because eruptions of huge volumes of pyroclastic materials had left the roof of the magma chamber unsupported, causing it to fracture and fall downwards into the chambers. Magma is also being drained from the chamber through fissures at depth. Collapse of the cone occurs, as it becomes a jumble of enormous blocks, some of which sink through the magma. This process is termed cauldron subsidence. This process may take a long time to complete and often happens in an extinct volcano. An example is the caldera of Tengger in Java, Indonesia. Crater lakes are formed when a caldera becomes filled with water sometime after it is formed. An example is the Crater Lake in Oregon, America. It is nine kilometers in diameter whose floor is 600 meters in depth, while the surrounding 6800-year-old caldera walls rise steeply 600 meters above it. Volcanic plugs are formed when lava solidifies in the pipe of an extinct volcano. Over time, the volcanic cone made up of less resistant rocks wears away, leaving behind the solidified volcanic plug. The Devil's Tower in Wyoming, USA is a great example of a volcanic plug. Lava plateaus are formed by the large outpourings of fluid lava from long narrow openings in the crust. During each eruption, the lava flows out from these openings, solidifies and builds up layer upon layer each time. A good example would be the Columbia Plateau in the USA. Geysers and Hot Springs A geyser is a hot spring that periodically erupts, throwing water into the air. Though that sounds simple, geysers are extremely rare. An eruption begins when pressure on a magma chamber forces magma up through the conduit and out the volcano's vents. When the magma chamber has been completely filled, the type of eruption partly depends on the amount of gases and silica in the magma. The amount of silica determines how sticky (level of viscosity) the magma is and water provides the explosive potential of steam. AND NOW, A VIDEO ABOUT VOLCANOES IN THE “PACIFIC RING OF FIRE” http://www.bing.com/videos/search?q=pacific+ring+of+fire&FORM=HDRSC3#vie w=detail&mid=D762B970F79BCFAB5938D762B970F79BCFAB5938