Factors Determining the Severity of Volcanic Processes
‘The extent to which volcanic processes represent hazards depends on where and when they occur’. Discuss this statement
A hazard can be defined as a situation that poses a threat to life, health, property or the environment. The severity and type of volcanic hazards that occur are mainly dependent on the type of magma. Volcanic processes can be split into two categories – primary hazards and secondary hazards. The primary hazards that can occur are pyroclastic flows, lava flows, tephra and poisonous gases. The secondary hazards include Lahars, volcanic landslides, tsunamis flooding and volcanic storms. The overall impact of volcanoes as a natural hazard varies greatly from one time and place to another. This is because it depends on the volcanic event, the population density of the surrounding area, the wealth of the area, the weather at the time and sometimes the culture of the inhabitants of the area. Vulcanicity is normally associated with plate tectonic processes and occurs along constructive plate margins, destructive plate margins or above hotspots.
The type of magma affects the severity and type of volcanic processes that occur because where there is basic (basaltic) magma, that is low is silica thus has a low viscosity, trapped gas bubbles are allowed to expand freely as they rise to the surface. This means the eruption fluid is free-flowing and therefore cannot suddenly erupt explosively. On the other hand, where there is acid (andesitic and rhyolitic) magma, the silica content is high therefore it has a high viscosity meaning gas bubbles struggle to expand and the magma often solidifies before it reaches the surface. These solidified sills and dykes cause a blockage that leads to a build up of pressure and eventually to a violent explosion.
The severity of volcanic hazards depends greatly on where they occur as location brings about many factors that determine how much of a threat the volcanic processes pose. One of the factors is the weather. For
A hazard can be defined as a situation that poses a threat to life, health, property or the environment. The severity and type of volcanic hazards that occur are mainly dependent on the type of magma. Volcanic processes can be split into two categories – primary hazards and secondary hazards. The primary hazards that can occur are pyroclastic flows, lava flows, tephra and poisonous gases. The secondary hazards include Lahars, volcanic landslides, tsunamis flooding and volcanic storms. The overall impact of volcanoes as a natural hazard varies greatly from one time and place to another. This is because it depends on the volcanic event, the population density of the surrounding area, the wealth of the area, the weather at the time and sometimes the culture of the inhabitants of the area. Vulcanicity is normally associated with plate tectonic processes and occurs along constructive plate margins, destructive plate margins or above hotspots.
The type of magma affects the severity and type of volcanic processes that occur because where there is basic (basaltic) magma, that is low is silica thus has a low viscosity, trapped gas bubbles are allowed to expand freely as they rise to the surface. This means the eruption fluid is free-flowing and therefore cannot suddenly erupt explosively. On the other hand, where there is acid (andesitic and rhyolitic) magma, the silica content is high therefore it has a high viscosity meaning gas bubbles struggle to expand and the magma often solidifies before it reaches the surface. These solidified sills and dykes cause a blockage that leads to a build up of pressure and eventually to a violent explosion.
The severity of volcanic hazards depends greatly on where they occur as location brings about many factors that determine how much of a threat the volcanic processes pose. One of the factors is the weather. For