Mount Merapi October 2010 Case Study

Causes 

The volcano and its eruptions were caused by the Indo Australian plate being sub ducted beneath the Eurasian plate. This caused great pressure and heat from friction between the plates which melted the Indo-Australian plate to form magma. The magma was lighter than its surrounding area so rose to the surface and caused a violent volcanic eruption. 
Furthermore, the volcanic eruption was particularly violent because Mount Merapi is a composite volcano with viscus lava that is more resistant to moving quickly, which in turn leads to the build up of pressure. 

The volcano is located on a destructive plate margin at a subduction zone and is part of the 'Pacific Ring of Fire' 

Primary effects

• On 25th October there were three major eruptive moments and hundreds of tremors. 
• On 26th October there was more explosive events. Pyroclastic flows spread 3km down the mountain.
• On 30th October there were further eruptions and lava continued to push into the dome. 
• Ash fell up to 30km away and 5km into the sky 15km away, villages were under 30cm of ash. The city of Yogyakarta was covered in ash. 
• Volcanic bombs and hot gases of up to 800 degrees Celsius spread over 11km away
• Sulphur dioxide was blown across indonesia and as far south as Australia. 

Secondary effects

• Vegetable prices increased because of the damage to crops
• Planes were grounded in Western Australia because of the risk of damage to aircraft from the ash cloud. 
• Ash, rock and lava deposited on the sides of the volcano washed down into towns by rainfall creating a lahar. 
• 4000 dairy cows and large areas of agricultural land were lost as they were damaged by heavy falls of ash. 
• Food shortages due to lost crops. 
• 34 people died as a result of pyroclastic flows. 
• Homes, roads, water supplies were destroyed
• 273 people died overall and 360,557 people were forced to flee their homes. 

Impacts

Negative 

• 273 people were killed - 176 died on the spot from pyroclastic gas, and 97 from accidents or other causes after being hospitalised 
• 577 people were injured with many suffering severe burns and chronic respiratory problems
• 360,000 people were displaced from their homes
• People, particularly farmers, lost their homes and livelihoods 
• The evacuation centres were overcrowded leading to poor sanitation, no privacy and serious disease risk
• Toursits will be put off visiting the location, which will affect the local economy

Positive 

• Ash from the volcano will eventually lead to more fertile soils in the area. 
• A conservation area has been set up around the volcano where it is unsafe to live. 

Responses 

Immediate 

• 210 evacuation centres were set up, either as tents, in schools, churches, stadiums or government offices.
• 1,600 people, either volunteers or military were part of the national aid response and distributed food, medicine and blankets.
• International aid was offered from organisations such as the Red Cross as a result of growing food shortage. 

Long Term

• Formal evacuation centres were eventually set up because buildings, such as schools and government offices, were needed for their official uses. 
• 2,682 people have had to be moved to new, safer houses permanently.
• The government is making money available to farmers to help replace their livestock. There is funding for more than 4000 dairy cattle
• The government has set up a special task force to support people that have been affected by the volcano either by family issues, or because they have lost their jobs. 
• They are also rebuilding infrastructure, roads, railways and reconstructing water supplies. 
• Further research is being carried out to find better ways of monitoring future eruptions.