Composite and shield volcanoes are found along plate boundaries. They have distinctive characteristics and can have both positive and negative effects on people and the landscape.
Case study - eruption in a developed country: Eyjafjallajökull
Iceland has several volcanoes and is situated on two tectonic plates – the North American plate and Eurasian plate.
The volcano, situated on the Eastern Volcanic zone in southern Iceland, began erupting lava on 20 March 2010. At first there was not much explosive activity. A second eruption then began beneath the ice cap near the summit of the volcano on 14 April. This eruption caused the melting of large amounts of ice, leading to flooding in southern Iceland.
Theinteraction of magma and water created a plume of very fine volcanic ash and gas over 10 kilometres (33,000 feet) high, which spread out and was carried by winds south-eastwards towards the Faroe Islands, Norway, and northern Scotland.
One of the main effects of the eruption and the ash cloud that followed, was the closure European airspace for seven days.
The economic cost of the eruption
Airlines lost a combined £130 million per day in lost revenues, according to the International Air Transport Association (IATA).
Europe's biggest tourism businesses lost between £5 million and £6 million per day.
As passengers looked for other ways to travel than flying, many different transport companies were able to benefit.
There was a huge increase in passenger numbers on Eurostar. It saw an increase of nearly a third, with 50,000 extra passengers travelling on their trains.
Exporters of perishable goods from the Caribbean and Africa were badly affected. Kenyan farmers reportedly resorted to dumping stocks of fresh food and flowers, which would otherwise have been sold to Europe. Kenya's economy lost £2.8 billion because of flights to Europe being cancelled.
Japanese car manufacturer Nissan halted production of several models for one day because it was not able to import parts from Ireland.
As a result of staff being stranded abroad, meetings being cancelled and delays to air mail, many businesses worldwide lost money.
The Iceland volcanic eruption disrupts air traffic
Environmental impact
Ash from the Eyjafjallajökull volcano deposited dissolved iron into the North Atlantic, triggering aplankton bloom
The mass-grounding of European flights prevented the emission of some 2.8m tonnes of carbon dioxide into the atmosphere (according to the Environmental Transport Association)
The eruption on 14 April set off a major flood in Iceland, when erupted lava partly melted a glacier prompting authorities to order 700 people to evacuate.
A road washed away by flood water, due to the melting Eyjafjallajökull glacier
Social impact
The people living in the rural areas 'downwind' of the volcano had to wear goggles and facemasks as the ash was so thick.
500 local cattle farmers and their families had to be evacuated from the area around the volcano.
Many of the roads surrounding the volcano were shut down.
The ash contaminated local water supplies. Farmers near the volcano were warned not to let their livestock drink from contaminated streams and water sources, as high concentrations of fluoride from the ash mixed with river water can have deadly effects, particularly in sheep.
