Volcanoes

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Volcanoes Distribution Volcanoes can be described as being tectonic hazards that occur in many parts of the world. The distribution of volcanoes is closely linked with the positioning of the tectonic plate boundaries across the globe. Today there are about 500 active volcanoes in the world. The world map of volcanoes in your atlas shows that the most volcanic activity occurs along the West coasts of North and South America, (along the Rockies and Andes) and the coasts of many Far East countries (in areas like Japan, China etc). The positioning of these volcanoes coincide with major plate boundaries. E.g. the volcanoes along the West coast of North America are the result of the Juan de Fuca plate converging with the North American plate. Another example is the volcanoes formed in the Andes Mountains are a result of the convergence of the Nazca and South American plates. Other areas that have high volcanic activity are along the plate boundaries of the Eurasian and African plates. Most of the volcanic activity on Earth occurs on the island of Iceland. Which is due to the formation of the Mid-Atlantic ridge, which is where two tectonic plates are diverging away from each other. Features Volcanoes release large amounts of energy from beneath the lithosphere, (Earth's crust and upper part of the mantle) and asthenosphere, (semi-molten mantle). During volcanic eruptions molten rock or magma rises up from the asthenosphere towards the surface as it's propelled by gases surrounding it. Some eruptions can occur through cracks in the Earth's surface called fissures. As magma reaches the surface, it's called lava. Common features o... ... middle of paper ... ...e media respond much faster. · This is due to the bureaucratic nature of multi level government, which requires numerous studies before anythin effective is accomplished. KT 38; Local, national and supranational responses. Local responses, cycled through shock, mourning and then anger for those who had 'allowed this to happen'. KT 39; Costs; economic and human. · Total economic damage of around $10 billion. · 42 died in Oakland, 60 miles from the epicentre. 400 injuries from the Cypress structure. · 59 water mains burst, but 100+ gas mains were ruptured. · 10 000 were left homeless, 62 died.· The Nimitz highway, and Cypress structure, and sections of the Bay Bridge collapsed, due to structural failure. They were subject to ten times the amount of force for which they were designed.

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