A volcano is a surface landform resulting from the extrusion of magma from underground as lava, ash, rocks, and gasses are erupted. Each year, around 60 major volcanoes erupt globally. 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 both human and physical that affect how hazardous a volcanic eruption may be.

One physical factor that affects how hazardous a volcano can be is the type of volcano. Composite volcanoes are formed by alternating layers of ash and rock and rock fragments unlike shield volcanoes, can be extremely dangerous. This is because of their sheer size, height and steep sides; they often form ice caps and glaciers at the peak, which melt due to the heat. When the water 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 over 50 miles; they can carry or destroy most things in their way including houses and trees. 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, when Pinatubo erupted it destroyed 42,00 homes and left 1.2 million people homeless. The eruption of Nevado Del Ruiz, in Columbia demonstrates the hazards associated with lahars as it caused 3400 ha of agricultural land to be lost as well as destroying virtually all roads in the area. 50 schools, 2 hospitals, 58 industrial plants and 343 commercial establishments were also damaged or destroyed. The lahars posed a