Tectonic Hazards - Case Studies Flashcards
Eyjafjallajokul Eruption: GENERAL
- Developed country, lies also above a hotspot, which produces even more volcanism which is why Iceland is a significant island above sea level, unlike the rest of the ridge
- Ice covered composite volcano on a divergent boundary (Mid - Atlantic Ridge)
- VEI of 3/4
Eyjafjallajokul Eruption: MAIN IMPACTS
- Social: ash cloud prevented travel in western Europe due to winds (10km high plume)
500 farmers had to be evacuated, ash caused respiratory issues - Economic: 4.7 billion total cost to the global economy, Kenyan flower exports to Europe stopped, affecting their GDP, airlines lost around £130 million per day, effects on global supply chains such as with Nissan due to delay of supplies of car parts
- Environmental: glacial outburst flood (raised local river levels by 3m + flooded farmland), ash contaminated water sources, acid rain
Eyjafjallajokul Eruption: RESPONSE
European Red cross helped evacuate people
- govt. declared a state of emergency, local authorities closed airport
24-hour hotline set up quick to help, shows their development status, automated telephone alerts for evacuation
- the National Centre for Atmospheric Science was called in to map the volcanic plume
Eyjafjallajokul Eruption: VULNERABILITY/PHYSICAL CONTEXT
- less economically/ knowledge vulnerable because of their development
- small population meant less people at risk
- physically vulnerable as it lies directly on a plate boundary
Physical context resulting in processes/hazards:
- disruptive ash plume due to cold meltwater that mixed with liquid magma, chilling it rapidly so it shattered into fine ash fragments
- Jokulhalp around the volcano due to icy climate: glacial floods
Kilauea Eruption: GENERAL
- Found on a Hawaiian atoll, a hotspot volcano on the Pacific plate with basaltic (runny) magma
- continuously erupting shield volcano
- wealthy USA, lots of farming on and around the volcano due to nutrient rich soils
- VEI of 0
Kilauea Eruption: IMPACTS
Social: 700 homes destroyed (May 2018 eruption), also other infrastructure e.g. highways, popular tourist attraction as is a natural park, volcanic smog ‘vog’ contributes to breathing problems
- Economic: eruptions affect tourism which the economy is dependent on: visitation to the National Park has declined by 1/3rd
- Environmental: 439 acres of new land added (2018 eruption), destroyed forests but enabled them to grow back stronger with fresh nutrients, air quality worsened due to large amounts of sulphur dioxide (acid rain) and smog
Kilauea Eruption: RESPONSE
- many know how to cope and live with the eruption due to how ongoing its eruptions have been (many live in Lava zone One, a high-risk area), continue to allow 2.6 million tourists
- volcano and National Park monitored by the USGS, observatory by the crater, rangers ensure walkers do not stray into dangerous areas,
- automated monitoring of the release of sulphur dioxide around the crater site using an ultraviolet camera, NASA satellites have also tracked gas releases
- people have been rescued by air after their escape routes were cut off by lava
Kilauea Eruption: VULNERABILITY/PHYSICAL CONTEXT
- reduced vulnerability due to the wealth of the islands and the USA
- many of the communities are vulnerable due to living in high-risk zones, but this is at their own risk
- older and ill residents are more vulnerable to health problems from constant ash and gas and the lack of doctors nearby
Physical context resulting in processes/hazards:
- mantle plume resulting in constant eruptions on the hotspot
Pinatubo Eruption: GENERAL
- Emerging country
- Stratovolcano, situated on the Island of Luzon, part of the Luzon Volcanic arc
- one of the largest and most destructive eruptions in history, with a VEI of 6
- convergent boundary: subduction of Philippine plate under Eurasian plate
Pinatubo Eruption: IMPACTS
- Social: 847 people killed, largest cause of death was collapse of roofs under heavy ash, many people were displaced to shanty towns in Manila, 1.2 million lost their homes
- Economic: Farmland destroyed by falling ash and pumice, 1991 harvest destroyed, $700 million in damages
- Environmental: 30km ash cloud, global cooling of 0.5C caused by ash in the atmosphere
Pinatubo Eruption: RESPONSE
Before the eruption: USGS scientists set up instrumentation to monitor it, volcanologists set up seismographs to monitor earthquakes and seismicity (April), tiltmeters, forecasted a volcanic hazards map of the areas that could be most susceptible
- Evacuation plans were decided and put into place – up to 40km outside
- one of the biggest aids in the aftermath was the USA, shipped shelter material
- government shelters and evacuation camps were set up
- Philippine National Red Cross also intervened serving up to 38 evacuation centres
Pinatubo Eruption: VULNERABILITY/PHYSICAL CONTEXT
physical context due to lying on a volcanic arc chain, being a multiple hazard zone, events can be triggered and are harder to manage – hot climate, typhoons, earthquakes
Physical context resulting in processes/hazards:
- Tropical climate meant Typhoon Yunya moved ashore at the same time, moving ash further with winds -> lead to majority of roof failures which killed/injured
- rain continued to create hazards over next several years (volcanic deposits remobilised into secondary mudflows (long term more affected by rain induced lahars)
- Lahars due to ash mixing with rainfall, moved down rivers, devastating bridges and flooding/burying in mud several lowland towns
