Analyse the Factors That Cause Differences in the Hazards Posed by Volcanoes Around the World (40 Marks)

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Analyse the factors that cause differences in the hazards posed by volcanoes around the world (40 marks) Volcanic hazards pose a risk to people and their property in both primary and secondary form. A volcano is an opening in the Earth's crust which lava, ash and gases erupt. A volcanic eruption can cause many deaths, illnesses, destruction of infrastructure, crops and livestock, all which will affect the economy and GNP of a country. There are many factors involved which cause differences in the severity of the destruction caused by a volcano, such as, locations of settlements, monitoring, plate boundaries and the economic status of a country, however these are different for each volcano around the world. I will be discussing factors that cause differences in hazards posed by volcanoes. I believe the most important factor is the location of a volcano and the type of volcano. The most explosive and therefore dangerous volcanoes are found on destructive plate boundaries (Over 80% of the worlds volcanoes occur at these boundaries) for example the eruption of the Nevado del Ruiz in Colombia on the 13th November in 1985 which killed over 25000 residents of Arenas and Armero. At destructive plate margins, the oceanic crust is denser than continental crust and is therefore subducts under the continental crust. Due to high temperatures in the mantle of around 3000 degrees centigrade, this oceanic crusts melts and then rises due to the convection currents in the aesthenosphere . As it joins with trapped seawater and sediment, it melts the overlying continental crust, and the magma plumes rise to the surface. They contain more silica so are more viscous, which plugs up the volcano, meaning pressure build up. This is why these volcanoes are so explosive. Another type of plate boundary are constructive, which is the margin between two diverging plates where new magma
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