The Theory of Plate Tectonics
In Earth, there are 4 main ares - the crust, the mantle, the outer core and the inner core. Heat is generated form the inner core and this heat is spread out throughout the mantle. The heat creates convection currents which causes friction with the outer crust. This friction causes the Earth's crust move with the convection currents which creates are various plates.
Mt. Tongariro Eruption 2012
On 7th August, 2012 Mount Tongariro in New Zealand erupted after being dormant for over a century. Mount Tongariro, one of three volcanoes in the centre of the North Island, became active with reports of loud explosions, spewing rocks and steam. The 1,978m volcano erupted but no casualties or damage have been reported after the eruption. The eruption shocked many due to its undetectable eruption that came with no warning.
Causes of the Tongariro Volcanic Eruption
Volcanoes are formed when there is a convergence with subduction between two tectonic plates. The Oceanic plate which is more dense than the continental plate dips under the continental plate creating a subduction zone. Mount Tongariro was formed by the convergence of the Pacific plate and the Indo-Australian plate as the Pacific plate dipped down the Indo-Australian plate. The volcanic eruption was caused as crust of the Pacific plate began to melt and formed magma chambers beneath Mount Tongariro. The Pacific plate constantly melted and formed many magma chambers which kept rising until it reached the top of Mount Tongariro for the volcanic eruption to occur.
Impacts of the Mount Tongariro Volcanic Eruption
![Picture](/uploads/1/4/3/2/14329546/1308046.jpg?397)
The unexpected volcanic eruption of Mount Tongariro devastated many families. Many homes were covered in volcanic ash and they were evacuated immediately. Luckily, BBC states that there were no casualties from the eruption. The eruption produced a massive ash cloud which layered the nearby forests, roads and homes. The social impact of the eruption is that roads and some homes such as Ketetahi hut about 1.5km from the epicentre of the eruption was significantly damaged with holes in the roof, floor and bunks. The volcanic ash also has produced more fertile soil for farmers near the eruption which can help obtain greater crop yields. Economic impacts include damaged houses having to be rebuilt as well as roads being have to cleaned and some remade. Much of the crops were destroyed and many stores will be closed until the damages have been repaired. Environmental impacts include the large amount of gases being emitted into our atmosphere such the green house gas carbon dioxide. The wind is said to have possibilities of carrying the ash cloud into other locations which will cause even more severe damage. Landscapes have been destroyed due to the lava flow of lahar and the forests have also been heavily covered in ash.
Differences between impacts volcanic eruptions in MECDs and LEDCs
![Picture](/uploads/1/4/3/2/14329546/3461742.gif?467)
In New Zealand, a MEDC (More Economically Developed Country) the citisens were securely evacuated even though the eruption of Mount Tongariro was not prepared for. In comparison to this event, the volcanic eruption in Montserrat in July, 1995 which killed 19 citizens was far more destructive. In Montserrat, a LEDC there were no well-developed form of communication which allowed the citizens to be informed of the eruption and due to its highly populated state, more casualties were reported. In LEDCs evacuation from the site is slower than that of MEDCs such as New Zealand. The eruption in Montserrat destroyed their capital city, Plymouth and over two thirds of its population were forced to flee from the country. MEDCs have better forms of communication which can help prevent needless casualties from volcanic eruptions and are able to evacuate civilians effectively.