4.a. case study indonesia impacts people experience result as a result of volcanic activity

Indonesia

location and background

located in central Java, near city of Yogyakarta being one of indonesia’s most active and dangerous volcanoes. very densely populated surrounding area with 1 mil plus living within 30km. indonesia= archipelago straddling tectonic plate boundaries. indonesia has a large number of active volcanoes; records of 80 that have erupted in historic times- coud be an underestimate. more than ¾ of indonesias inhabitants live within 100km of a volcano that has erupted in past 10,000 years. indonesia has suffered more eruptions causing fatalities (114) and damage to infrastructure (195) than any other country in the world. similar to japan much of the landscape of indonesia is dominated by volcanic peaks and indonesias history, culture and the personal experience of its people are closely tied to volcanoes

tectonic setting is complex with widespread subduction along the entire 3000km length of the indonesian archipelago. much is an island arc formed by subduction of indo-australian plate beneath the eurasian plate. meanwhile to east of chain of islands the continental shelf of northern australia is in collision with eurasian. these plate movements produce very high levels of seismicity and volcanicity. feature of volcanism in indonesia is the large number of volcanoes that are highly explosive, exemplified by the cataclysmic eruption of krakatau in 1883= also generated a devasting tsunami. around 80% of dated volcanic eruptions in indonesia have occurred since 1900.

merapi indonesia

strato-volcano which reaches nearly 3km in altitude. it is highly active with eruption events in 1994, 1997, 2001 and 2006. on each occasion a dome developed in the crater which eventually collapsed producing pyroclastic flows. the force of these eruption was 3 to 4 VEI

reasons why people choose to live in tectonically active locations

these locations offer people a place to live, to have employment and to bring up families. those with limited economic resources= limited choice of where to occupy. indonesia itself was created by volcanic activity. plate subduction occurring produces vast amounts of molten material which has accumulated to form the archipelagos which make up the land mass of indonesia. slopes of volcanoes attract settlement as weathered lava produced fertile soils especially in wet tropical regions. as indonesia sits astride the equator, it is possible to grow 2 and 3 crops a year on some volcanic soils. intensive farming therefore supports very high population densities. also provide opportunities for tourism. there are guided hikes when activity levels are low and provides income for local guides, guesthouses and transport providers

vast geothermal energy potential and is beginning to exploit this. currently only about 3% of the total electricity generation comes from geothermal but there are plans to increase this. the 300 MW sarulla power plant has been active since 2018 earliest. from 2022 onwards the company has been focusing on technology and mitigation strategies to restore full output eg use of acid resistant alloy casings, chemical clean out methods to remove scaling, drilling of new wells to increase generation capacity back to target of 330 MW.

eruption and the impacts people experience

VEI 4 eruption between 26 oct and 12 nov 2020 affected people living around the volcano. pyroclastic flows extended 4km to the north, 11.5km to the west, 7km to the east and 15km to the south. lava bombs were thrown kms from the summit in all directions. the eruption happened at the start of the rainy season, triggering lahars fed by ash from the eruption and from earlier eruptions. ash falls forced the closure of yogyakarta airport for over a fortnight and emissions of sulphur dioxide caused acid rain to fall over a large part of the region. overall 370 people were killed, 280 were injured while approx 400,000 in the vicinity of the volcano became refugees

economic impact on the country

localised- large numbers of livestock were killed, and ash fall and pyroclastic flows amounting to 130 mil m³ of material destroyed crops and infrastructure such as buildings, power lines and bridges. the destruction of crops reduced farmers incomes too. estimated economic losses reached 100s of mil. tourism in the region temporarily declined due to safety concerns. small businesses and local markets were disrupted reducing income for traders and informal workers. transport routes were blocked, limiting access to markets and delaying trade

national- gov spent large amounts on emergency evacuation, temporary housing, food aid and infrastructure repair. airport= closed= distrupting trade and tourism to central java. there were large long term costs of rebuilding housing and relocating communities. gov budgets were strained, diverting money from other development projects. long term- reconstruction created short term employment. lava tour tourism later developed, turning disaster into economic opportunities. volcanic ash improves soil fertility over time so agricultural productivity can recover. investment in infrastructure rebuilding improved roads and services in some areas, supporting future economic growth

environmental impact on the country

negative- forests and farmland buried by ash and pyroclastic material and lahars altered river channels and increased flood risk. acid rain damaged vegetation. river systems clogged with sediment and wildlife displacement in affected zones. air quality declined due to ash clouds, affecting both ecosystems and human health. water supplies were contaminated by ash and volcanic material, impacting drinking water and irrigation

positive- volcanic ash adds minerals to soils which increase fertility. creation of new landforms and ecosystem regeneration over time. new habitats can develop as vegetation gradually recolonises volcanic deposits

political impact on country

indonesian gov ordered large scale evacuations with over 400,000 people relocated to emergency shelters. increased funding for volcanic monitoring and early warning systems and strengthened role of indonesias volcanology agency (centre for volcanology and geological hazard mitigation). highlighted challenges of managing risk in a lower middle income country with dense population near volcanoes. improved disaster management policies and coordination between national and local gov. raised public awareness and political pressure to improve hazard management and preparedness. international cooperation increased with aid and expertise supporting indonesias response

overall impacts

the evacuation orders likely presented far higher death tolls due to the effective monitoring even though there were 370 deaths. economic losses were significantly locally but limited nationally. long term environmental recovery and improved soil fertility may offset short term agriculture losses. living near merapi remains attractive due to fertile soils and economic opportunities however indonesia faces greater challenges in relocation and long term resettlement due to limited resources. overall impacts were severe in short term but demonstrate how effective management can reduce long term national consequence