Volcanic Hazards

To what extent can preparedness and planning mitigate the effects of volcanic hazards? (40 marks)

A volcanic hazard is a situation that poses a threat to life, the environment, and infrastructure after a volcanic eruption. Volcanoes are formed at various plate boundaries, such as at mid oceanic ridges where plates are moving apart, for example at the Mid Atlantic ridge. They also occur on or near subduction zones. The ‘ring of fire’ tends to be where the most violent volcanic activity occurs. The scale of destruction a volcano has is heavily dependant on whether the eruption occurs in an MEDC or an LEDC and the way in which these country’s prepare and plan for the possibility of a volcanic eruption. Additionally, many human and physical
The first eruption in Montserrat in 1995 was completely unplanned and prepared for. The volcano had been dormant for more than 300 years and so the eruption came as a complete surprise. The Montserrat Volcano Observatory was recognized shortly after the first eruption of the Soufriere Hills Volcano on July 18th 1995. The stations are located around the volcano and detect the ground movements caused by local earthquakes and dome collapses. Occasionally, large earthquakes outside Montserrat are also recorded. The seismic signals are monitored 24 hours a day at the Observatory. The second eruption on 25 June 1997 affected Montserrat in a number of ways, even though the volcano observatory had been put in place. This could be due to Montserrat being an LEDC, and therefore it cannot afford to implement expensive eruption detection technology. Exclusion zones, however, were put in place to ensure that minimal amount of damage would be done, following the eruption. The eruption had many impacts on the environment; the main component of the eruption causing the most devastating effects was the pyroclastic flow (hot ash, rocks and gas), which alone killed around 19 local people. Following the eruption, a total of at least 4 square kilometers of land was covered by the deposits from the pyroclastic flows and surges The fine grained pyroclastic surges broke and flattened trees. In some areas there was no vegetation left at all, vegetable beds were bare of plants and the soil was extremely hard. The lack of planning and preparedness the eruption had shocking effects on the local people as well. The volcanic eruption destroyed between 100 -150 houses. The houses were buried by debris from the pyroclastic flow, burned by the hot pyroclastic surges, or set alight by the intense heat in the atmosphere. Most of the houses destroyed were