Analyse the Factors That Cause Differences in the Hazards Posed by Volcanoes Around the World.

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A volcano is a surface landform resulting from the extrusion of magma from underground as lava, ash, rocks, and gasses are erupted in various proportions. A hazard is something that poses a threat to life, the environment or property. Volcanoes can compromise all these things through the many hazards volcanoes presents. These include lahars, flash flooding, landslides, pyroclastic flows, ash clouds and many others. Each year, around 60 major volcanoes erupt globally. How hazardous each eruption is depends on a variety of physical and human factors. This essay will analyse how physical volcanic properties interact with human variables to make certain volcanoes more hazardous than others. This will be identified through the numerous recorded eruptions from different countries at different stages of development. Since the degree of impact an earthquake has is measure on both the Richter and the Mercalli scale, it must be reasonable to assume that the power of an eruption is representative to the degree of how potentially hazardous the event may be. Eruption explosiveness can be measured by the Volcanic Explosivity Index. The higher the Volcanic Explosivity Index, the greater the potential hazard. The eruption type is a huge factor in the differences in the degree of hazards posed by volcanoes around the world. This greatly relates to the plate margin the volcano or volcanic belt is situated upon. There are three areas on the crust where volcanoes can form. These are; over hotspots, along constructive plate margins and along destructive plate margins. The area the volcano forms on usually determines the type of lava found at the volcano. Effusive volcanoes are more commonly formed at constructive plate margins where plates diverge. Here, lava tends to be basaltic meaning it is low in silica content. The low proportion of silica allows gases to expand and thus
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