Analyse the Factors That Differences in the Hazards Posed by Volcanoes Around the World
Analyse the factors that differences in the hazards posed by volcanoes around the world (40 marks)A hazard is a naturally occurring event that has the potential to cause loss of life or economical damage. The hazards that are caused by Volcanoes can vary in size and depends on the scale of the eruption; if it is a small eruption then it has minimal impacts, whereas a larger eruption can cause mass disruption. There are many factors that affect how hazardous a volcano may be and in this essay I will be analysing each factor and the impacts that it has. One factor that may affect how hazardous a volcano may be depends on the type of volcano itself. Composite volcanoes are formed by alternating layers of ash and fragments of rock and, unlike shield volcanoes, can be extremely dangerous! This is because, due to the sheer size and height of them, they often form ice caps and glaciers at the peak, which melt due to the heat. When the water all runs down the volcano, it mixes with other materials such as mud and rock, causing lahars. Lahars can rush down streams and valleys at high speeds and can travel distances of 50 miles or more, moving at such a fast speed, means that they can carry or destroy most objects in their path; this includes houses, trees and even large boulders. When they get further downstream, they start to move slower and eventually end up covering everything in a thick layer of mud. This can be one of the most deadly hazards, as it destroys houses and can leave people homeless. This can then lead to secondary problems, such as an unbalanced population structure or overpopulated areas elsewhere. An example of this would be the eruption of Nevado Del Ruiz, located in Columbia 1995.
The location of a volcano also has a massive impact on how hazardous an eruption may be. Volcanoes are found in three different places; Constructive plate boundaries, Destructive plate boundaries and Hotspots. It is said that the most dangerous volcanoes are formed at destructive plate boundaries; this is where two plates are colliding, causing the denser plate to subduct under the other, meaning that the trapped gases within the plate make the magma more acidic. This can cause Rhyolitic lava which is highly explosive and poses a great threat to us! As well as this, the location also plays a role because it not only depends on where the volcano is, but the surroundings of it. For example, Krakatau is a volcanic island situated in Indonesia, between the islands of Java and Sumatra and is surrounded by the ocean. This volcano wasn’t seen as much as a threat, as we thought the ocean would act as a barrier and protect us. However, in 1883 this huge volcano erupted, which caused a giant tsunami at 120ft tall, due to the volcano being blown apart and falling into the sea, destroying any nearby islands and killing over 36,000 people; making it a huge factor that differences in the hazards posed by volcanoes.