Hazardous Earth - Case Study - Mount Merapi 2010 - Volcano Impacts Flashcards
What plate boundaries does Indonesia lie on? Which plates?
- Convergent
- Oceanic (Indo-Australian)
- Continental (Eurasian)
What features do you see at this plate boundary?
- Volcanoes
- Transform lines
- Ocean trenches
- Earthquakes (occur at all plate boundaries)
Why is Indonesia a hugely tectonic region?
- Widespread subduction along 3000km archipelago
Why is Mount Merapi particularly active?
- It is a young volcano - very active
How many active volcanoes are in Indonesia?
- 129
Which island of Indonesia does Merapi sit on?
Island of Java
What % of Indonesia’s inhabitants live within 100km of a volcano that has erupted in the past 100 years?
- More than 75%
Why do people in Indonesia chose to live in areas vulnerable to eruptions? (6)
- Traditional ties to an area- may be less inclined to leave
- Religious significance- people see volcanoes as spiritual
- Agriculture- fertile soil = high yield, crops grow quickly
- Tourism- income for locals (potentially no other jobs in area)
- LIDC- lack of choice = cheaper housing on slopes of volcanoes
- Physical barrier (ocean)- have to fly to leave- may not be possible
What is Mount Merapi’s eruption history?
Erupting regularly since 1548
1994, 1997, 2001, 2006
What type of volcano is Merapi?
Strato-volcano (reaches nearly 3,000 m)
How far/what direction is Mount Merapi from Yogyakarta city?
28 km north
When was the Mount Merapi eruption?
- 2010
- 26 October - 12 November
What was the VEI scale of the eruption?
- 3-4
What material was erupted? (3)
- Lava bombs
- Ash
- Sulphur dioxide
Where there any signs that an eruption was imminent in 2010? What were the stages before the eruption? (4)
- Late October 2010, Centre for Volcanology and Geological Hazard Mitigation (CVGHM)- pattern of increasing seismicity from Merapi had emerged
- Lava from Merapi began flowing down Gendol river valley (23 - 24 October)
- 23 - 24 October- officials stated about 500 volcanic earthquakes recorded on the mountain/magma risen to about 1 km below surface due to seismic activity
- 25 October- Indonesian govt raised alert to highest level/warned villagers in threatened areas to move to safer grounds
What were the social impacts of the 2010 eruption? (4)
- 367 deaths/277 injured
- Health- 410,000 refugees in vicinity of volcano- refugee camp toilets = unhygienic- many at shelters experienced headaches, respiratory infection, high blood pressure//sulphur dioxide = irritation to skin, eyes, respiratory tracts
- Livelihood- lots of refugees- farmers lost their jobs (ash = loss to crops- fear for food shortages) = many forced to become miners- sell sand from eruption/take on jobs initiated. by govt (i.e. cleaning up volcanic ash)
- Psychological distress- survey 2 years after event = Cangkringan district experienced large distress in relation to environmental impact of event
What were the economic impacts of the 2010 eruption? (4)
- Total estimated cost = £450 million (mainly due to farming losses)
- Farming/plantation- damage to rice, fruit, vegetables- economic loss from agriculture = £13 million
- Tourism- 2010, domestic tourists decreased 30%/international tourists decreased 70%
- Flights- flights through ash cloud = engine failure = 2,500 flights cancelled for safety reasons/Yogyakarta airport closed for fortnight
What were the environmental impacts of the 2010 eruption? (3)
- Ash plumes- altitudes of 18 km, fell 30 km from peak of volcano- 2-4 cm thick layer of ash on ground = damaged 200 hectares of forest//albedo effect BUT: fertilisation of the soil = benefit farmers
- Lahars/pyroclastic flows- Cangkringan/Kemalang = most affected- rice fields, farms, infrastructure, river, soil = damaged- significant damage observed 2 years later
- Sulphur dioxide- reacts with environment = acid rain- 12,000-15,000 m sulphur dioxide cloud above Indian Ocean = alberdo effect BUT: not enough to create observable difference in global temp
