Case Study - Mount Merapi

November 2010

Mount Merapi, Indonesia

Causes:

• The eruption came from a composite cone with a VEI of 4
• The volcano is situated at a subduction zone, where the Indo-Australian plate is sliding beneath the Eurasian plate
• The eruption was explosive, with thick andesitic lavas and large pyroclastic flows which caused further damage
• Large clouds of ash filled the sky and then fell on surrounding areas up to 40km away

Impacts:

• 353 deaths (some were killed in the panic of evacuating the area), 500 injured
• 350,000 people successfully evacuated before and during the eruption
• Economic losses = US$0.6 billion
• The rice harvest on the mountain and surrounding area was lost due to the ashfall (social impact)
• Forested areas on the mountain were destroyed by the pyroclastic flows
• Lahar followed the eruption

Pre-eruption:

• Initial monitoring of the mountain before the disaster predicted that an eruption was likely
• Evacuation schemes were put in place for all people within 20km of the volcano
• Many people decided to ignore the warnings. The 'spiritual guardian of the mountain', and his followers, were some of these people left behind

Post-eruption:

• Refugee shelters, of tents and tarpaulins, were set up far enough away from the volcano for those who had evacuated
• Local airports were closed due to the volcanic ash plumes
• Government aid agencies delivered food, water and hygiene kits (including face masks so people didn't inhale too much ash)

\