Casestudy: Indonesia volcanoes LIDC

Question 1

What makes Indonesia distinct as a country damaged by tectonic hazards?

Answer 1

• Indonesia has suffered more fatality causing eruptions and accompanying damage to infrastructure than any other country in the world.

Question 2

What type of volcano is Mt Merapi, in Indonesia?

Answer 2

• A highly active stratovolcano

Question 3

Describe Indonesias tectonic setting.

Answer 3

• Complex, with widespread subduction along the length of the archipelago.
• Much of Indonesia is an island arc, formed by subduction of the Indo-Australian plate beneath the Eurasian plate.
• Indonesia has a large number of volcanoes that are highly explosive.

Question 4

What are reasons why people choose to live near volcanoes in Indonesia?

Answer 4

• Fertile soil for agriculture.
  Volcanic ash can deposit nutrients, enhancing soil fertility in volcanic Indonesian regions - this supports Indonesias primary sector for crops such as rice, coffee and tobacco.
• Economic opportunities
  Volcanic regions offer Indonesia natural resources such as minerals , sand and rocks for construction. In addition, Mt Merapi supports a thriving tourism industry for activities such as trekking and cultural experiences which generates income.
• Lack of alternative options :(
  Population density in Indonesia forces many to settle in hazard-prone areas such as volcanic slopes - as economic constraint limit access to safer land.

Question 5

When did the key eruption (used in case study) occur in Indonesia?

Answer 5

2010

Question 6

Why is Indonesia especially at a higher risk of lahars as a hazard?

Answer 6

Indonesian volcanoes emit large quantities of ash, and accompanied by Indonesias humid tropical climate with high levels of rainfall, lahar threat is very high.

Question 7

Describe negative impacts people experience as a result of Indonesian volcanic eruptions

Answer 7

• Death and injury
  In the 2010 Merapi eruption, 361 people were killed in this eruption - with many as a result of pyroclastic flows and, in survivors, associated respiratory issues. 277 were injured, and many eventually became part of the death toll due to burn injuries and illnesses.
• Frequent evacuation
  Approximately *400,000 became refugees from the local vicinity following the eruption of Mt Merapi - this disturbed daily life and left many individuals homeless.
• Damage to agriculture and farming.
  Large numbers of livestock surrounding Mt Merapi were killed. In addition, ash and the pyroclastic flows amounting to 130 million m cubed of ash destroyed crops.
• Destruction of buildings and infrastructure.
  Over 2000 residencies were destroyed, contributing to the amount of refugees. The hazard of the tephra emitted further led to collapse of buildings, power lines and bridges.

Question 8

What were the economic impacts of Indonesian volcanic eruptions on the country?

Answer 8

• Destruction of crops.
  Indonesian crop farms of tobacco, rice and vegetables disrupted farmers livelihoods - as further loss of livestock and income cost millions. This affected trade in the country and left many poor farmers bankrupt. Despite this, over a longer temporal period the volcanic ash benefitted crops as it enhanced soil fertility.
• Tourism decrease.
  Volcanic eruptions lead to a temporary loss of income for the tourism industry due to safety concerns. This affected Indonesia on a national scale as ash fall led to the closure of Yogyakarta airport, disrupting economic activities for general tourism (as well as transport and trade).
• Cost of rebuilding —> $158 million
  The cost of rebuilding infrastructure amounted to $158 million, which was only a small proportion of the 781million cost of recovery overall, this placed strain on the national budget as Indonesia is still considered an EDC.

Question 9

What were the environmental impacts of Indonesian volcanic eruptions on the country?

Answer 9

• Disruption to the biosphere and hydrosphere
  Thick ash deposits destroyed vegetation and polluted rivers.
• Lahars became a prominent hazard
  Lahars occurred due to the eruption occurring during the rainy season from between November to March - this caused long-term soil erosion and flooding in river valleys - which could arguably have overridden the positive effects of enhanced soil fertility.
• New landscapes
  On a positive note, previous Indonesian eruptions have created new volcanic landscapes - for example the creation of Lake Toba in a caldera has helped tourism.