1
Q
assess the role of governance in determining the scale of a volcanic disaster (12)
A
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
2
Q
how can hydrometeorological hazards contribute a tectonic disaster
A
- 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)
3
Q
what is the lithosphere?
A
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.
4
Q
explain the secondary hazard of acid rain
A
caused when gases such as sulfur dioxide are released into the atmosphere.
5
Q
what is land-use zoning? how does it help prepare for earth hazards?
A
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.
6
Q
how can population density and urbanisation affect the vulnerability and ability to recover from a hazard?
A
- 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
7
Q
explain kilauea and its management
A
- 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
8
Q
what is the pressure and release model (PAR model)
A
- 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
9
Q
what are the challenges of multiple hazards
A
- 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
10
Q
what is administrative governance?
A
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.
11
Q
explain paleomagnetism
A
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
12
Q
why is the Philippines a multiple hazard zone?
A
- 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.
13
Q
explain the role of development in merapi
A
- 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
14
Q
explain the physical context and eruption of eyjafjallajokull in 2010
A
- 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
15
Q
what is governance?
A
Governance is the sum of the many ways individuals and institutions manage common affairs. It is a root cause of vulnerability.
16
Q
explain the five strands of vulnerability
A
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
17
Q
explain the primary hazard of volcanic gas
A
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
18
Q
explain the use of high-tech monitoring for modifying vulnerability and resilience
A
- 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
19
Q
what happens at a convergent (oceanic-continental) boundary?
A
- 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
20
Q
explain seafloor spreading and ridge push
A
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
21
Q
what is the asthenosphere?
A
this lies beneath the lithosphere and is semi-molten on which the plates float and move
22
Q
what is the overall idea that the PAR model shows
A
it shows the interrelation between a hazard and its wider context that being:
- human context (vulnerability)
- physical context (processes and factors)
23
Q
primary hazards of volcanoes
A
pyroclastic flows
tephra + ash flows
volcanic gas
lava flows
24
Q
what are intraplate volcanoes?
A
- isolated plumes of convecting heat (mantle plumes) rise towards the surface which melts the oceanic crust above to generate basaltic volcanoes that erupt continuously, the plume is stationary but the plate moves slowly above it
- effusive eruptions, low viscosity, main hazard is lava flows
- shield volcanoes. e.g. Kilauea
- produces a chain of volcanic islands = atolls
25
what is andesitic lava and where does it form?
- composite/strato volcanoes
- intermediate levels of silica, gas content, medium viscosity
- eruption is violent and moderately explosive
- e.g. Merapi
- forms when subducted oceanic plate melts and mixes with seawater, lithosphere and continental plate rocks
26
what are the impacts of Kilauea
- It releases up to 2000 tonnes of sulphuric dioxide a day so greatly contributes to acid rain and climate change
- Lava has created over 100km of new land which is fertile for agriculture like sugar cane
- the lava boiled a 400-year-old lake until it evaporated and killed a number of sea creatures
- One eruption was explosive and sent a plume of volcanic ash 30,000 feet into the air
- the 2018 eruption led to the decimation of 700 homes
- recovery efforts of 2018 puna eruption was $800k
- Ohia forest covered in 20 to 30ft of lava
- blocked roads
- Generates 2.6 million tourists a year, contributes to the economy, local business to fund monitoring projects, gov have branded it as a tourist attraction
27
explain the secondary hazard of jokulhlaups
flood water resulting from rapid melting of a glacier/ice cap during an eruption. causes sudden floods that are very dangerous, affecting accessibility, transport of aid. e.g. in Iceland
28
how does the physical context influence a place and its disaster
1) Tropical regions
- Antecedent conditions resulting in a higher risk of lahars through the mixing of magma and rainwater, e.g. Merapi’s lahars took out hundreds of homes and contaminated their water supplies through the acidic lava and ash, economic impacts $600 million, multihazard zones (Asian monsoon belt), ring of fire
- Monsoon period
2) Its geographical location will influence its overall economic impact for the wider world
- Icelandic volcano’s location along many major flight paths
- The prevailing westerly winds in the mid-latitude zone and its stable polar jet stream meant that the ash was in the same direction for most of the eruption stage, affected 10 million air passengers
3) Snow and ice cover
- Encouraging Jökulhaups whereby the snow and ice in glaciers melt which causes sudden floods
- Its snow and ice cover led to a huge ash cloud being ejected into European air space, 110 million m cubed of ash ejected in one week
Gas and ash accumulates underneath the snow and ice cover and as pressure builds up this will lead to an explosive eruption, spreading the ash even further, seen in Iceland
29
what happens at a divergent boundary?
- as plates move part, magma rises from the mantle, this is mainly basaltic lava which has a low viscosity and lower silica content
- less gases will be trapped and it is less explosive (effusive)
- shield volcano normally (Eyjafjallajokull was an exception)
- main hazard is lava flows but different physical contexts will create other primary and secondary hazards too
- ridge push( the bubbling magma causes plates to move apart)
- it creates great rift valley (continents) where crust is stretched and land between faults collapses
30
what is the diverting of lava flows for mitigation?
- methods include building barriers and digging channels to try to divert the flows into safer directions
- while these methods have led to some successes, in general they are fairly ineffective.
this is because:
- the path taken by lava is hard to predict making it hard to know where to build the walls and channels
- the terrain has to be suitable (downward slope)
- stopping the lava from flowing towards one community may push it towards another.
31
what are the 3 main physical processes and factors with a volcanic eruption?
- subduction
- divergence
- mantle plumes
32
explain the social, economic and environmental impacts of the Icelandic volcano
Social
- 800 residents in southern Iceland were evacuated due to the eruption melting the ice and therefore leading to floods
- it caused flight delays all over the world, leading to a disruption in travel
- 10 million air passengers affected
Economic
- 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.
- those who deliver stock by plane were badly affected as they couldn't make any sales as they had no stock to sell, affected economies all around the world.
- nissan declared a suspension in the production of 3 models because supply parts had been disrupted, stopped the production of 2000 vehicles, affecting the wages of employees
- Considerable disruption to tourism and business, with total economic impacts estimated at over $3 billion
- workers were temporarily unemployed (e.g. $2 million per day loss in Kenyan flower exports)
Environmental
- Erupted 110 million m cubed of ash in one week up to an altitude of about 9km. 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
- Perishable Kenyan agricultural products for the UK rotted in warehouses
- the massive reduction of air travel led to an estimated 1.7 million tons of carbon dioxide from entering the atmosphere
33
what are the impacts of Kilauea?
social
- destroyed more than 200 homes
- blocked roads
economic
- Lava has created over 100km of new land which is fertile for agriculture like sugar cane
- Generates 2.6 million tourists a year, contributes to the economy, local business to fund monitoring projects
- Produces fertile soils for the local population
environmental
- It releases up to 2000 tonnes of sulphuric dioxide a day so greatly contributes to acid rain and climate change
- One eruption was explosive and sent a plume of volcanic ash 30,000 feet into the air
34
explain the strand of vulnerability of dynamic pressures
1) leads to lack of investment into:
- infrastructure
- education (no warning systems in place)
- Training
- Appropriate skills
- Local investment
- Local market
- Media freedom
- medical care
2) macroforces
- Rapid population increase
- Rapid urbanisation
- Expenditure
- Deforestation
- Decline in soil productivity
35
categorise the primary and secondary hazards by those which have a physical process cause and those influenced by physical context
physical process cause (subduction, divergence, mantle plume)
- pyroclastic flows (pinatubo)
- tephra (pinatubo)
- lava flow (Kilauea)
- ash (pinatubo)
- gases (all)
```
influenced by physical context (climate/lithology)
- tephra (Iceland)
- ash (Iceland)
- lahar (pinatubo)
jokulhlaup (Iceland)
```
36
what are shield volcanoes like?
- basaltic lava (less viscous due to less silica) so doesn't trap gases so not explosive, but effusive
- Shallower gradient due to the lower viscosity of lava meaning it can travel further before cooling (basaltic lava)
- Usually at oceanic hotspots or mid-ocean ridges
- Formed from layers of lava
37
explain the primary hazard of lava flows
molten rock (magma) that has reached the earths surface. flows but speed depends on the lava’s viscosity which depends on the silicon dioxide content, will burn settlements
38
explain the structure of the earth
crust
- also known as the lithosphere, the uppermost layer of the earth which is the thinnest and least dense
- oceanic crust is only 7km thick whereas continental crust can be up to 70km thick
mantle
- semi-molten and a temperature gradient towards the core generates convection currents
- depth from 700km to 2890km below the crust
inner core
- similar composition to the outer core. its over 5150km below the earth's crust. the inner core is solid iron due to the extreme pressures it experiences. temperature of over 5000ºC. the core's high temperature is a result of:
- radiogenic heat produced form radioactive decay
- primordial heat left over from the earth's formation
outer core
- dense, semi-molten rocks containing iron and nickel alloys. at a depth of 2890km to 5150km below the earth's surface. temps of 4500-6000ºC
39
explain the secondary hazards of lahars
combination of rock, mud and water which travel quickly down the sides of volcanoes. These can occur when the heat of the eruption causes snow and ice to melt or alternatively when an eruption coincides with heavy rainfall and is mixed with the ash (high energy).
40
what is risk/damage threshold?
refers to the classing of different natural hazards based off their magnitude and scale of damage.
When a hazard’s magnitude exceeds the risk/damage threshold the hazard is dangerous to the local population. This can be because the population is vulnerable or the hazard has an extremely high magnitude.
41
explain Kilauea volcano, Hawaii
- 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
42
explain the strand of vulnerability of unsafe conditions
1) Fragile physical environment
- Dangerous locations (landslide prone)
- Unprotected infrastructure (shanty towns)
2) Fragile local economy
- Livelihoods at risk
- Low income levels
- high inequalities
3) Vulnerable society
- Special groups at risk (elderly)
4) Public actions
- Lack of preparedness
- Epidemic disease
43
what are the geographical factors affecting the vulnerability and a community's resilience
- population density
- isolation/accessibility
- degree of urbanisation
44
how would you answer: “Assess the role of governance in determining the vulnerability and resilience of a community to a tectonic hazard” (12)
- Intro: root cause of vulnerability
- Invest into warning systems
- Can control how safe the buildings are, building and infrastructure
- Reduce inequality in a population and reliance on primary industry
- Increase awareness and educate people on what to do (Egypt)
- Yet arguably a country needs to be developed to have good governance and development controls how resilient the economy is (New Zealand vs Nepal)
- Some hazards will still make a population vulnerable no matter how prepared they are, e.g. Japan
45
explain the strand of vulnerability of root causes
1) limited access to:
- power
- structure
- resources
2) ideologies
- political system (corruption)
- economic system
46
definition of a hazard
it is a potential threat to human life and property, it can either be hydro-meteorological or geophysical
47
what happens at a convergent (oceanic-oceanic) boundary?
- very similar to continental to oceanic but the oceanic plate that is denser is subducted leaving an ocean trench
- through the friction in the Benioff zone it causes the melting of the mantle causing submarine volcanoes
- this creates island arcs and eventually an atoll, which is when lava cools above sea level and creates new land
- this can create tsunamis
- e.g. the Aleutian Islands
48
explain the social, economic and envrionmental impacts of mount merapi
social
- 200,000 people were made homeless by the eruption and a further 320,000 were displaced
- ash, rock and lava deposited on the side of the volcano were washed down and caused lahars which wiped out many houses and bridges, these lahars had runout distances exceeding 15km
- socio-economic reasoning as people lost their jobs, emerging country based on agriculture (primary) and due to widespread countryside being wiped out, a large proportion of employment was affected than in a developed country
- 353 killed from the initial eruption, further 5000 due to the earthquake that occurred 50km SW to Merapi
economic
- $600 million damage
- vegetable prices increased because of damage to crops leading to famine as many could no longer afford food
- planes grounded in Australia due to risk of aircraft damage from ash cloud
- general economic consequences like building damage and paying for evacuation centres
environmental
- ash cloud dispersed huge amounts of sulphur dioxide and so an increase in acid rain but also localised breathing difficulties and an international cooling effect
- water supplies contaminated by acidic lava and ash but it did lead to more fertile soils in the area
49
explain the physical context and eruption itself of mount merapi 2010
- mount merapi is located in SE Asia in the country of Indonesia, island of Java
- Merapi is a 9551 ft tall mountain located on the ring of fire, forming a composite containing the andesitic lava.
- Merapi is situated at the subduction zone where the indo-australian plate is sliding beneath the Eurasian plate.
- multiple hazard zone, suffering from earthquakes as well as monsoon rains
Eruption
- This began an increasingly violent series of eruptions that continued into November.
- The scale of this eruption reached 4 on the volcanic explosivity index (VEI)
- Due to the high content of silica and gas which became trapped, and built up an intensive amount of pressure, its eruption was violent and sudden. The nature of this eruption led to the generation of lava domes which when collapsed causing pyroclastic flows and longer explosions.
- clouds of ash and gas were spewed 14.5km high up into the sky
50
what are the different mechanisms that could cause plate movement?
1) mantle convection
- radioactive elements in the core of the earth decay which produce a lot of thermal energy
- this causes the lower mantle to heat up and rise, as the magma rises it cools down becomes more dense and begins to sink back down through frictional drag
- these are convection currents, they push the plates
2) slap pull
- where older and denser oceanic crust will subduct breath less dense cont plate. the density of the oceanic plate pulls it downwards towards subduction zone at the edge of ocean, this drags the rest of the plate with it
51
what are the three types of vulnerability in the PAR model?
```
root causes (governmental)
dynamic pressures (people)
unsafe conditions (location)
```
52
explain the global distribution of volcanoes
- predominately located along the ring of fire
- convergent boundary in the north Pacific Ocean forms the Aleutian islands
- they can occur at convergent (destructive) margins where subduction creates friction to then melt the plate at the Benioff zone. this happens around the Aleutian islands
- they can occur at divergent (constructive) margins where magma rises plates pull apart, e.g. mid Atlantic ridge in Iceland
- they can occur on hotspots where a hot magma plane breaks a hole in a plate to form new land (intra-plate), e.g. Kilauea
53
what is basaltic lava?
- ocean hotspots, shield volcanoes
- low silica, water and gases
- eruptions are gentle but effusive
- e.g. Kilauea
54
what are composite/strato volcanoes like?
- andesitic lava forms cone volcanoes with steep sides
- more likely to have pyroclastic flows
- traps gases and so it is more explosive
55
what were the predictions systems and response for mount merapi
prediction systems
- started to be monitored in 1942 using seismometers some of which are still used today
- Magnetic measurement and tiltmeters have been installed and help to predict as small changes in local magnetic fields have been found to coincide with eruptions and tiltmeters to show the inflation of the volcano as magma rises.
- During the late-mid 1900s many of the stations were deprived of equipment due to a lack of funding yet since then there have been considerable improvements in regards to the supply of new equipment
response
- 210 evacuation centres set up
- international aid was offered from organisations such as the red cross
- 1600 people, either voluntary or military were part of the national aid response
- 2700 people were moved to safer homes permanently and is making money available to farmers to help replace their livestock
- formal evacuation centres were eventually set up because buildings, such as schools and government office were needed for their official use
56
explain the primary hazard of tephra and ash flows
molten and solid rock fragments ejected from explosive eruptions that collect on roofs and cause collapse. it can be transported by jet-streams
57
explain the primary hazard of pyroclastic flows
a dense mixture of superheated tephra and poisonous gases which are 1000ºC. Due to their high speeds, pyroclastic flows are extremely dangerous and can cause asphyxiation for anyone unfortunately caught by the flow. it appears as a turbulent fast moving ash cloud
58
what are the secondary hazards of volcanic eruptions
jokulhlaups
lahars
acid rain
59
what were the responses to the Icelandic volcano?
- the Icelandic Red Cross provided food for the farming population, counselling and psychological support, in particular for traumatised children
- the Netherlands Red Cross set up 1500 emergency beds for those whose flights were cancelled
- airports were closed due to the risk of the ash cloud
- aid was given to anybody physically affected by the eruption
- NCAS scientists work now closely with the met office to monitor and model the ash plume from the volcano using the 2 research aircraft and computer models
- the ash was dug up from the bottom of rivers to make the rivers deeper
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