The effects of volcanic hazards
The effects of volcanic hazards
To what extent can planning and preparedness mitigate the effects of volcanic hazards? A hazard is a situation that poses a level of threat to life, health, property, or environment. There is a very big difference that helps prepare for a volcanic hazard and that is whether you are in a MEDC or a LEDC. In a MEDC monitoring volcanic zones and potential hazards is an option many LEDC’s don’t have. In Italy at Mt Etna they have Geochemical monitoring programs currently run by INGV which focus on the analysis of temporal changes, chemical changes and seismic activity. This option open to the Italians is not an option for LEDC who don’t have the wealth or public education to set up these stations. An example of an LEDC with no planning and prevention plans is Mount Pinatubo- Philippines, Its last eruption in 1991 was completely unplanned for. Mt Etna has a history of fairly frequent eruptions, all of which came with impacts on the surrounding area. Socially the town of Zafferana Etnea was threatened by the largest volume of lava in hundreds of years, this can also be seen as an economic impact.
In 2002 a huge column of ash was thrown up from the biggest eruption in recent years and was deposited as far away as Libya. Seismic activity associated with these eruptions caused the eastern flanks of the volcano to slip by 2m, causing structural damage to many houses. Lava flows completely destroyed the tourist station at piano Provenzana and part of the tourist station at Rifugio Sapienza. The airport at Catania was forced to close as the runways were covered in ash. The winter tourist industry was affected as visitors stayed away due to safety concerns. It is arguable however that these impacts would have been much worse if the area wasn’t already prepared for an eruption. To protect themselves from the hazards of an eruption the government and locals used methods of protection and prediction to aid them for future eruptions. To protect themselves in 1669 the town’s people of Catania dug a tunnel to divert lava flows away from their homes.
This was very effective because it reduced the risk of the village being damaged by the lava. An earth barrier of 750,000 cubic metres was built across the southern end of the valle de above (eastern crater) in 1991 to protect the town of Zafferana. This was a temporary measure whilst other protective measures were put in place. These were effective for smaller eruptions but in Spring of 1992 this and small barriers leading down into the valley leading off Zafferana were overtopped. This meant that these barriers were only effective for smaller eruptions and therefore limits the amount that the aspect of preparedness can mitigate volcanic effects.
However, when compared to the Mount Pinatubo eruption of 1990. Here the area was completely unprepared and the resulting impacts speak for themselves; 350 people were killed and 200,000 homes were destroyed. However it is very difficult to blame these larger impacts on the fact that the area was unprepared because the size of the eruption was actually much larger and the type of hazard was different to that of MT Etna; Tephra was the primary cause of the housing damage and consequently 300 of the 350 people killed were killed by collapsed roofs.
If the houses had been structurally reinforced then this may have reduced the number of casualties, however this is not an option for a ledc country as reinforced buildings are expensive to make. Another option is to move people out of the area of hazards and build a society in a safer area. This comes with many disadvantages as the area around the volcano has very fertile soil and precious minerals in the ground, with the infrequency of eruptions it is worth the risk to the very deprived people living in the country.
A cheaper alternative to prevention is prediction. It involves equipment set out to monitor seismic and gaseous activity around the volcano in order to predict the next eruption. A study of the previous eruption history of a volcano is also an important prediction method. At present, research is being conducted to see if it is possible to predict the time of an eruption accurately using the shock waves that are produced as magma approaches the surface, expanding cracks and breaking through other areas of rock. This would mean that people could live in the area and use the volcanos resources and then abandon the area pre-eruption.
Overall the more planning done around volcanic eruptions the more we can reduce the impacts up to a certain extent. The difficulty being to measuring how effective planning and preparedness is to mitigate the volcanic hazards is that every eruption is different in terms of what hazards they present and therefore the impacts reflect how strong the hazards were. A super volcanic eruption such as Yellowstone national park would be devastating worldwide and planning and preparedness cannot mitigate its effects. However for small observable volcanic eruptions planning and preparedness can severely reduce the risks with the eruptions.
University/College: University of Chicago
Type of paper: Thesis/Dissertation Chapter
Date: 22 September 2016
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