Tectonics Flashcards
assess the role of governance in determining the scale of a volcanic disaster (12)
Governance
- This is a root cause of vulnerability according to the PAR model
- Administrative and political governance is essential for the control of land use planning as well as the implementation of evacuation centres and the efficiency of the funnelling of international aid during the response stage of the hazard management cycle
- Good governance will ensure they have the resources in place in order to ensure efficient response as well as protecting the infrastructure
- E.g. Kilauea, actively monitoring the volcano, use of GPS measurements in monitoring of the eruption by the Hawaiian volcano observatory who are working with the USGS
- Government branding it is as a tourist attraction has led to 2.6million tourists coming to visit a year which allows for further funding into monitoring projects
- Seismometers detect minor earthquakes, monitored daily by volcanologists
- However: one may argue that this is reliant on the development of a country as it is arguably only with a certain degree of development that a country can have a government that successfully ensures the protection of their population from an eruption
Development
- This follows onto the degree of preparation in mitigating severe impacts from a volcanic eruption, the education of the people
- If they are developed then this is likely to lead to more advanced management strategies as well as having high quality infrastructure making them more resilient
- This follows onto their degree of administrative government as they are likely to have more plans in place if they are in a developed country
- However this follows onto the economic impacts of a volcanic disaster, interconnected economy means it has a greater economic impact
- E.g. Icelandic volcano
- NCAS scientists now work closely with the met office to monitor and model the ash plume from the volcano using the 2 research aircraft and computer models
- the IATA estimated that the airline industry as a whole would lose out on £130 million a day, total loss of £1.1 billion, over 95,000 fights were cancelled which disrupted over 10 million passengers
- nissan declared a suspension in the production of 3 models because supply parts had been disrupted, stopped the production of 2000 vehicles
Physical context
- The climate and geographical location play a large role in influencing the scale of disaster
- Multiple hazard zones often mean that the secondary hazards of an eruption are exacerbated, e.g. lahars and jokulhlaups
- E.g. Phillippines, multiple hazard zone in which they are exposed to monsoonal rain as well as homing around 300 volcanoes, Mount Merapi’s 2010 eruption led to lahars which spread over 15km due to the mixture of the magma rock and the antecedent conditions causing the downfall of huge masses of molten rock, ash and mud down the strato volcano, andesitic lava, led to the contamination of water supplies as well as the destruction of hundreds of homes, overall economic impact of $600 million, GEOGRPAHICAL MODIFICATION impacted through its timing during the monsoonal period
However: the impact of the physical context was lessened through the presence of good governance, they were able to set up formal evacuation centres and reduce the social impacts of t
how can hydrometeorological hazards contribute a tectonic disaster
- Heavy rainfall can saturate the ground through infiltration and percolation, decreasing its stability. When the hazard hits it means there is more likely to be landslides.
- Increased amount of water acts as a lubricant making the shaking more intense in the first place
- It can lead to the creation of lahars when there is heavy rainfall at the time of an eruption. Leads to the destruction of homes and access roots, hampering evacuation/rescue missions
- If a storm surge or heavy rain occurs soon after, causing flooding then impacts can be exacerbated (lack of sanitation = disease exposure, lack of food if stores or crops are ruined)
what is the lithosphere?
consists of the crust and the rigid upper section of the mantle and is approximately 80-90km thick. this is the section of the earth that is divided into seven very large plates and a number of smaller ones. the plates are divided into oceanic and continental plates.
explain the secondary hazard of acid rain
caused when gases such as sulfur dioxide are released into the atmosphere.
what is land-use zoning? how does it help prepare for earth hazards?
it is a process by which local government regulate how land in a community may be used.
in areas at risk from eruptions, land-use zoning is an effective way to protect both people and property.
in areas at high risk from volcanic eruptions + tsunamis:
- any settlements tend to be limited
- certain types of structures and facilities will be prohibited
- some communities may be resettled (those near shore moved to higher ground for tsunamis)
land-use zoning is common in wealthy countries, but less so in some developing countries, often why it causes more deaths in developing countries.
how can population density and urbanisation affect the vulnerability and ability to recover from a hazard?
- High population density not only inevitably means more people are affected but it can also hamper recovery as it can reduce the efficiency of evacuation teams due to a dense urban environment
- The degree of urbanisation is significant. More urban means a higher population density and so more people affected. Often also increases slum housing. However rich urban areas often have more mitigation in place, e.g. cross braising.
- Isolated areas will have trouble recovering and rebuilding as they’re difficult to access, e.g. in the Himalayas helicopters are used which are expensive
explain kilauea and its management
- One of five shield volcanoes on the island of Hawaii, over an oceanic hotspot on the Pacific plate, as the pacific plate has moved over this hotspot over millions of years new volcanic islands have formed and old volcanoes have become extinct as their magma supply runs out
- It has been erupting since 1983 however in May 2018 this eruption intensified
- Its frequent eruptions are usually effusive, the volcano has produced a river of flowing lava that reached the sea 10 miles south of the volcano, they have basaltic lava which makes it very runny
management
- Gas emissions monitored, warnings issued about air pollution levels
- Seismometers detect minor earthquakes, monitored daily by volcanologists
- Weak planning laws and growing population has to led to build in at risk areas
- Good governance has led to fast response, evacuating 2000 people in 2018 eruption through the use of land convoys and helicopters
- FEMA team set up mobile air quality monitoring system during the eruption
what is the pressure and release model (PAR model)
- risk can be predicted using PAR model and two hazard risk equations
- PAR model is often known as the disaster crunch model
- it resembles a ‘nutcracker’ as pressure increases from both sides, release of pressure tacking vulnerability to reduce the disaster
It states that vulnerability is a process that starts with root causes. These are political and economic systems that control who has power in a society. Through a series of processes called dynamic pressures, these root causes can lead to unsafe conditions. The process from root causes to unsafe conditions is called the progress of vulnerability.
root dynamic unsafe
causes pressures conditions
DISASTER
hazard
- if the area affected is highly vulnerable from a range of social and environmental factors the disaster is more greatly experienced
- e.g. Haiti had a poor political system which is a root cause of vulnerability, this is because the government is highly corrupt and the humanitarian aid funds did not reach the people in their entirety meaning people and businesses could not cover as quickly meaning the disaster was greater
what are the challenges of multiple hazards
- One hazard can increase the likelihood of other hazards
- Different hazards happening in a short amount of time can make resilience for government and communities hard as it drains resources and stretches the ability of emergency services to respond
- Operating in a near constant state of emergency
what is administrative governance?
is the system of policy implementation and requires good governance at both central and local levels. It requires functioning enforcement of building codes, land-use planning, environmental risk and human vulnerability, monitoring and safety standards.
explain paleomagnetism
the idea that currents flip every 40,000 years and so the magnetic orientation flips too
- it results from magma locking in the earth’s magnetic polarity when it cools, scientists can use this reconstruct past plate movements
- it proves that new ocean crust is created by the process of sea floor spreading and mid ocean ridges
- it led to the discovery that the ocean floor is getting progressively older the closer to the coast and that newer coast must be produced by molten rock inside
why is the Philippines a multiple hazard zone?
- Located on a (convergent) plate boundary creating major risks from both earthquakes and volcanoes
- Archipelago meaning susceptible to tsunamis
- Climatic hazards due to being in storm belt regions
- Mountainous terrain can lead to landslides. Landslides are common due to steep topography, high levels of deforestation and high rainfall
- Its northern and eastern coasts face the pacific ocean (the world’s most tsunami prone ocean)
- Tropical monsoon climate so is subject to heavy annual rainfalls
- The Philippines has 47 volcanoes, 22 of which are active. This means over 30% of he population lives within 30km of a volcano.
explain the role of development in merapi
- Developing countries tend to have a large percentage of their economy based around agriculture, the Philippines have 30% of their economy based around agriculture, this sector is the most vulnerable to volcanic eruptions through the presence of ashfall and so overall developing nations are more vulnerable to the effects of a volcanic disaster than developed nations
- E.g. Merapi, they experienced severe socio-economic impacts through the destruction of their agriculture, the loss of crops led to famine as well as 200k made homeless
explain the physical context and eruption of eyjafjallajokull in 2010
- the distribution of ash was across main flight paths and airports disrupting European and North American flights due to the prevailing westerly winds in the mid-latitude zone and a stable polar front jet stream during the eruption which directed the ash in the same direction for most of the eruption stage
- strato volcano with andesitic lava
- snow and ice cover led to more explosive eruptions due to the pressure, as well as impact of Jökulhaups
- seismic activity began at the end of 2009 and slowly increased in intensity until the 20th march 2010 with a small eruption (rated 1 on VEI). more violent eruptions began on the 14th April, 2010
- it disrupted most of Europe when during its second phase of eruptions ejected a massive ash cloud into European air space, created the largest air travel disruption since WW2
what is governance?
Governance is the sum of the many ways individuals and institutions manage common affairs. It is a root cause of vulnerability.
explain the five strands of vulnerability
1) Physical vulnerability
- When people live in hazard-prone areas in building that offers little protection, lack of infrastructure
- Action: move away from hazard-prone areas
2) Economic vulnerability
- dependant on the economic stays of individuals and nations so affected by assets
- poor residents do not have to money to afford recovery and preparation
- Action: Introduce housing insurance, compensation
3) Social vulnerability
- When a household or community is unable to support the disadvantaged people within it, e.g. political isolation may exist for the poor, females, elderly and rural residents
- elderly populations are more vulnerable
- high population density
- Action: Government could provide money
4) Knowledge vulnerability
- When people lack education and training and therefore understanding.
- This leads to the lack of warning or evacuation systems in place
- Action: They must educate people on efficient evacuation routes
5) Environmental vulnerability
- lack of natural resource depletion
- resource degradation making settlements vulnerable, those dependant on resources
- high pop density leading to people being forced into riskier areas
- being on plate boundaries
- Action: They must relieve population pressures by creating new services
explain the primary hazard of volcanic gas
water vapour seeps from cracks and produces fumaroles and geysers. water mixes with sulphur dioxide to create acid rain and the particles reflect solar radiation. due to their potency, volcanic gases can travel long distances
explain the use of high-tech monitoring for modifying vulnerability and resilience
- technological monitoring systems for volcanic eruptions, earthquakes and tsunamis allow scientists and others to learn more about these natural processes, to predict them further in advance
- GIS helps to create hazard maps and manage hazards more effectively
- early warning systems use scientific instruments to detect signs that a volcanic eruption or tsunami is about to occur
- mobile-phone technology is used to communicate rapid warnings and coordinate preparation activities. when seismographs detected P waves off japan’s NE coast the Japanese government set out text messages via phones warning of the earthquake
what happens at a convergent (oceanic-continental) boundary?
- the subduction of the denser oceanic plate leads to friction and letting of the continental crust in the Benioff zone
- this causes magma to rise and accumulate in the magma chamber
- this causes an explosive eruption of andesitic lava with high gas and silica content (viscous), volcanic plug
- pyroclastic flows due to enormous amounts of ash and gas which are created in the explosion
- composite/strato volcano forms with a steep sided cone, e.g. pinatubo 1991
explain seafloor spreading and ridge push
seafloor spreading
- youngest crust at ridge and oldest at subduction zone
ridge push
- the idea that some of the mantle will go up and push the crust outwards, the plate sinks under its own weight
what is the asthenosphere?
this lies beneath the lithosphere and is semi-molten on which the plates float and move
what is the overall idea that the PAR model shows
it shows the interrelation between a hazard and its wider context that being:
- human context (vulnerability)
- physical context (processes and factors)
primary hazards of volcanoes
pyroclastic flows
tephra + ash flows
volcanic gas
lava flows
