1.1 Tectonic processes and hazards Flashcards
1
Q
Types of natural hazard (2)
A
- hydro-meteorological (caused by climatic
processes) - geophysical (caused by land processes)
2
Q
Define intra-plate earthquakes
A
- Earthquakes near the middle of plates
- plates have pre-existing weaknesses which become reactivated, forming seismic waves.
- e.g. an intraplate earthquake may occur if solid crust, which has weakened over time, cracks under pressure.
3
Q
Define inter-plate earthquakes
A
- an earthquake that occurs at the boundary between two tectonic plates
- usually at conservative, collision, or destructive boundaries
4
Q
What is a volcanic hotspot?
A
- hotspots are situated amongst the centre of plates
- a localised area of the lithosphere which has an unusually high temperature due to the upwelling of hot molten material from the core
- At hotspots, magma rises as plume
- e.g. Hawaii
5
Q
Define the OFZ (Oceanic Fracture Zone)
A
a belt of activity through the oceans and along the mid-ocean ridges through Africa, the Red Sea, the Dead Sea
6
Q
Define the CFZ (Continental Fracture Zone)
A
a belt of activity along the mountain ranges from Spain through the Alps to the Middle East and to the Himalayas.
7
Q
Describe tectonic trends since 1960 (4)
A
▪ total number of recorded hazards has increased
▪ number of fatalities has decreased - some spikes during mega disasters.
▪ population growth means total number of people being affected by tectonic hazards is increasing
▪ economic costs increased significantly - due to development as infrastructure in more developed countries costs more to repair, and increasing number of insurance policies
8
Q
Why is reporting disaster impacts difficult? (4)
A
▪ Depends on whether you look at the direct deaths or indirect deaths due to secondary impacts
▪ Location: rural and isolated areas are hard to reach and so hard to collect data from them. Similarly, data may be difficult to collect in areas with very high population densities.
▪ Different methods may be used by different organisations so as a result different sources may quote different figures
▪ The number of deaths quoted by a government could be subject to bias
9
Q
4 layers of the Earth’s structure
A
- crust (lithosphere)
- mantle (asthenosphere)
- outer core
- inner core
10
Q
Describe the crust (3)
A
- uppermost, thinnest, least dense, and lightest layer
- Oceanic crust is only 7km thick
- continental crust can be up to 70km thick.
11
Q
Describe the mantle (4)
A
- Largely composed of silicate rocks, rich in iron and magnesium
- semi-molten
- temperature gradient (towards the core) generates convection currents, which causes to the circulation of the mantle and may contribute to the lithosphere’s plate tectonic movement.
- from 700km to 2890km below the surface
12
Q
Describe the outer core (2)
A
- Dense, semi-molten rocks containing iron and nickel alloys.
- 2890km to 5150km below the Earth’s surface.
13
Q
Describe the inner core (3)
A
- Similar composition to the outer core.
- over 5150km below the Earth’s surface
- solid due to the extreme pressures it experiences
14
Q
Why does the inner core experience such high temperatures? (2)
A
○ primordial heat left over from the earth’s formation
○ radiogenic heat produced from radioactive decay
15
Q
Describe convection currrents
A
- hot magma rises because it becomes less dense with heat
- magma cools at the top as it is further away from the heat source
- it then becomes more dense and sinks back down
- cooler magma is reheated and begins to rise again
16
Q
Describe a destructive plate boundary between a continental and oceanic plate (7)
A
● Denser oceanic plate subducts below the continental.
● leaves a deep ocean trench.
● oceanic crust melts as it subducts
● extra magma created causes pressure to build up.
● Pressurised magma forces through weak areas in the continental plate
● composite volcanoes erupt through the continental plate
● Fold mountains occur when sediment is pushed upwards during subduction.
17
Q
Describe a destructive plate boundary between 2 oceanic plates (3)
A
● Heavier plate subducts leaving an ocean trench and fold mountains
● Built up pressure causes underwater volcanoes bursting through oceanic plate.
● Lava cools and creates new land called island arcs.
18
Q
Describe a collision plate boundary (5)
A
● 2 continental plates
● Both plates are not as dense as oceanic so lots of pressure builds.
● there is no subduction of continental crust.
● Pile up of continental crust on top of lithosphere due to pressure between plates.
● Fold mountains formed from piles of continental crust.
19
Q
Describe a constructive plate boundary between 2 oceanic plates (3)
A
● Magma rises in between the gap left by the two plates separating, forming new land when it cools.
● Less explosive underwater volcanoes formed as magma rises.
● New land forming on the ocean floor by lava filling the gaps is known as sea floor spreading (as the floor spreads and gets wider).
20
Q
Describe a constructive plate boundary between continental plates (4)
A
● Any land in the middle of the separation is forced apart, causing a rift valley.
● Volcanoes form where the magma rises.
● Eventually the gap will most likely fill with water and separate completely from the main island.
● The lifted areas of rocks are known as horsts whereas the valley itself is known as a graben.
21
Q
Describe a conservative plate boundary (5)
A
- Between any crust, the parallel plates move in different directions or at different speeds.
- No plates are destroyed so no landforms are created
- When these plates move, a lot of pressure is built up.
- On oceanic crust, this movement can displace a lot of water.
- On continental crust, fault lines can occur where the ground is cracked by the movement.
22
Q
Describe paleomagnetism and how it provides evidence of seafloor spreading
A
- As new rock is formed and cools the magnetic grains within the rock align with the magnetic poles
- Our poles switch periodically. Each time these switch the new rocks being formed at plate boundaries align in the opposite direction to the older rock.
- On the ocean floor either side of constructive plate boundaries, Geologists observed that there are symmetrical bands of rock with alternating bands of magnetic polarity.
23
Q
What are different mechanisms causing plate movements? (3)
A
- slab-pull
- ridge-push
- convection currents
24
Q
Describe ridge-push
A
- The slope created when plates move apart has gravity acting upon it as it is at a higher elevation.
- Gravity pushes the plates further away, widening the gap
25
Describe slab-pull
- When a plate subducts, the plate sinking into the mantle pulls the rest of the plate (slab) with it, causing further subduction
26
How has tectonic theory changed?
- tectonic movement isn't fully understood.
- Previously, convection currents were thought to be the primary cause of plate movement.
- However, researchers now believe that Slab Pull is the primary mechanism for plate movement
- convection currents seem too weak to move massively dense plates.
27
What causes an earthquake?
- Plates do not perfectly fit into each other so plates can become stuck due to the friction
- the convection currents in the asthenosphere continue to push, which builds the pressure
- the plates eventually give way.
- All of this pressure is released in a sudden movement, causing a jolting motion in the plates.
- This is responsible for seismic movement spreading throughout the ground in the form of seismic waves
28
Define the focus (or hypocentre) of an earthquake
- the point underground where the earthquake originates from
29
Define the epicentre of an earthquake
- the area above ground that is directly above the focus
30
Name the 4 types of seismic waves
- primary
- secondary
- love
- rayleigh
31
Describe primary waves (P-Waves)
- Travels through solids
- Compressional
- Vibrates in the direction of travel
- Travels at 4-8 km/s
32
Describe secondary waves (S-waves)
- Vibrate at right angles to direction of travel
- Travels only through solid rocks
- Travels at 2.5 - 4 km/hr
33
Describe love waves
- Near to ground surface
- Rolling motion producing vertical ground movement
- Travels at 2-6 km/hr
34
Describe Rayleigh waves
- Vertical and horizontal displacement
- Travels at 1-5 km/hr
- Compressional
35
Which types of wave are most destructive?
- Secondary and Love waves are the most destructive as they have large amplitudes. - Due to their different speeds, these different waves will hit a location at different times.
- The aftershocks that survivors feel are these different types of waves arriving after each other.
36
What affects the intensity of a seismic wave?
- Intensity will decrease further from the epicentre, as waves lose energy as they travel.
- this does not mean that impacts felt or damage caused will always decrease further from the epicentre as other factors affect a location's vulnerability
37
Factors affecting an area's vulnerability to earthquakes (5)
- geology
- geographical location (whether the earthquake occurs near the sea or intraplate)
- education of locals,
- durability of buildings
- mitigation
38
Name 3 secondary impacts of earthquakes
- soil liquefaction
- landslides
- tnusamis
39
Describe liquefaction
● Affects poorly compacted sand and silt.
● Water moisture within the soil separates from the soil particles and rises to the surface.
● This can cause the soil to behave like a liquid, which can cause building subsidence or landslides.
40
Describe landslides caused by earthquakes
● The shaking caused by the earthquake can weaken or damage cliff faces, hills and snow material.
● Unconsolidated material or loose rocks can collapse.
● Landslides can travel several miles and accumulate material on the way.
● Risk varies with topography rainfall, soil and land use.
41
Describe tsunamis
● When an oceanic crust is jolted during an earthquake, all of the water above this plate is displaced
● This water is then pulled back down due to gravity. The energy is transferred into the water and travels through it like a wave.
● The water travels fast but with a low amplitude
● As it gets closer to the coast there is friction between the sea bed and the waves.
● This causes the waves to slow down and gain height
42
Where do tsunamis usually occur?
- Tsunamis are generated generally in subduction zones at convergent plate margins.
- Most tsunamis are found along the Pacific ring of fire
- hence the most vulnerable countries are often located in Asia or Oceania
43
Physical factors affecting tsunami impacts (5)
- geographical location
- Duration of the event
- Wave amplitude and distance travelled
- Gradient of the continental shelf
- The shape of the land - bays will funnel and concentrate tsunami waves.
44
Human factors affecting tsunami impacts (4)
● Population density of area hit, if the population is higher than more people are likely to be affected
● Coastal defences (e.g. Tsunami walls)
● Warning & Evacuation Systems
● Level of economic and human development
45
Describe strato (composite) volcanoes
- steep-sided cones formed from layers of ash and acidic lava flows.
- lava is viscous so it cannot travel far down the slope of the volcano before it cools.
- usually found at destructive plate margins.
- Most composite volcanoes contain complex internal networks of lava flows which contain intrusive (below ground) igneous features
- e.g. Mount Fuji, Mount St Helens
46
Describe the eruption of a composite volcano
- The eruptions from these volcanoes may be a pyroclastic flow rather than a flow of lava.
- When composite volcanoes erupt they are explosive and pose a threat to nearby life and property.
- Eruptions are explosive due to the thick, highly viscous lava that is produced by composite cone volcanoes.
47
What is a caldera?
- A caldera is a volcanic crater
- They form when an explosive eruption destroys the cone and the magma chamber below is emptied.
- Without magma providing support below a caldera is formed when the sides of the volcano collapse.
48
Describe a shield volcano
- Shield volcanoes are low with gently sloping sides and are formed from layers of lava.
- Eruptions are typically non-explosive. Shield volcanoes produce fast flowing basic (fluid) lava that can flow for many miles.
- Eruptions tend to be frequent but relatively gentle.
- Although these eruptions destroy property, death or injury to humans rarely occurs.
- Shield volcanoes are usually found at constructive boundaries and sometimes at volcanic hotspots.
- e.g. Mount Kilauea and Maunaloa on Hawaii.
49
Define strombolian eruption
- The effects are impressive but not particularly dangerous.
- They eject short bursts of lava 15 to 90 meters in the air.
- The lava has a fairly high viscosity, so gas pressure builds up before the material can be ejected from the volcano.
- Lava flows from Strombolian eruptions are not common though they do produce small amounts of ash.
50
Define vulcanian eruptions
- Vulcanian eruptions involve violent gas explosions that blow out sticky plugs of lava.
- These fragments build up cones of ash and pumice.
- Lava is very viscous and solidifies rapidly.
- The eruption usually clears a blocked vent and releases a significant amount of ash.
51
Define Vesuvian eruptions
- vesuvian eruptions involve very large blasts of gas that force large ash clouds into the sky.
- They are more violent than Vulcanian eruptions.
- Ash falls on the surrounding area and lava flows can also happen.
52
Define Plinian eruptions
- most explosive and violent of volcanic eruptions.
- They produce huge plumes of ash and gas that typically takes the shape of a huge mushroom cloud.
- They are highly explosive and the AD79 eruption that buried Pompeii was one of these.
- started by highly viscous magma that has high gas content.
- As the magma emerges it depressurizes and this allows the gas to expand, propelling pyroclastic material as high as 45 km in the air
- These eruptions can last for days and create a sustained and tall eruption plume, which drops a huge amount of tephra, fallen volcanic material, on surrounding areas.
- Additionally, a Plinian eruption can produce extremely fast-moving lava flows that destroy everything in their path.
53
Primary hazards caused by volcanic eruptions (4)
- lava flows
- pyroclastic flows
- tephra and ash flows
- volcanic gases
54
Describe lava flows
– Streams of lava that have erupted onto the Earth’s surface
55
Factors affecting magma types (3)
- silica content
- viscosity
- gas content
56
How does magma's silica content, viscosity, and gas content affect an eruption's explosivity?
- As viscosity, silica content, and gas content increase, explosivity increases
57
Describe pyroclastic flows
- a mixture of hot dense rock, lava, ash and gases which move very quickly along the surface of the Earth.
- Due to their high speeds, they are extremely dangerous and can cause asphyxiation for anyone caught by the flow.
58
Describe tephra and ash flows
- When pieces of volcanic rock and ash are blasted into the air.
- This can cause serious damage to buildings, which can collapse under the weight of ash or tephra
59
Describe volcanic gases
- Gases like sulphur dioxide and carbon monoxide are released into the atmosphere.
- Due to their potency, volcanic gases can travel long distances.
60
Secondary hazards caused by volcanic eruptions (3)
- lahars
- jokulhaup
- acid rain
61
describe 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.
62
Describe a jokulhaup
– Snow and ice in glaciers melt after an eruption which causes sudden floods that are very dangerous
63
Describe acid rain
- caused when gases such as sulfur dioxide are released into the atmosphere by an eruption and dissolve in rain
64
Define multiple-hazard zone
- Multiple hazard zones are places where two or more natural hazards occur, and in some cases interact to produce complex disasters.
- Examples are California, Indonesia and Japan.
65
Features of multiple-hazard zones (4)
- tectonically active and so earthquakes (and often eruptions) are common
- geologically young with unstable mountain zones prone to landslides
- often on major storm tracks either in the mid-latitudes or on tropical cyclone tracks
- suffer from global climate perturbations such as ENSO
66
Define disaster
A serious disruption of the functioning of a community or society involving human, material, economic and environmental losses which exceeds the ability of the affected community or society to cope using its own resources
67
What is the Risk equation?
Risk (R) = (Hazard (H) x Vulnerability (V))/ capacity to cope (C)
68
When might a place be high risk?
- Their capacity to cope is low.
- They are quite vulnerable.
- The hazard is large/ high intensity.
69
What is the difference between a hazard and a disaster?
- A disaster will only occur when a vulnerable population (one that will be significantly disrupted and damaged) is exposed to a hazard
- Different organisations will define a hazard and disaster differently, based on their interests and what they believe is most important
70
What does the Park Model show?
- The Park Model is a graphical representation of human responses to hazards.
- The model shows the steps carried out in the recovery after a hazard, giving a rough indication of time frame.
- The steepness of the curve shows how quickly an area deteriorates and recovers.
- The depth of the curve shows the scale of the disaster
71
4 stages of the Park model
- pre-disaster
- relief
- rehabilitation
- reconstruction
72
Describe the relief stage of the Park model
- hours-days after event
● Immediate local response - medical aid, search and rescue
● Immediate appeal for foreign aid - the beginnings of global response
73
Describe the rehabilitation stage of the Park model
- days-weeks after event
● Services begin to be restored
● Temporary shelters and hospitals set up
● Food and water distributed
● Coordinated foreign aid - peacekeeping forces etc.
74
Describe the reconstruction stage of the Park model
- weeks-years after the event
● Restoring the area to the same or better quality of life
● Area back to normal - ecosystem restored, crops regrown
● Infrastructure rebuilt
● Mitigation efforts for future events
75
How can the Park model be used?
- The model works as a control line to compare hazards.
- An extremely catastrophic hazard would have a steeper curve than the average and would have a slower recovery time than the average
76
What is the Pressure and Release Model used for?
- used to analyse factors which cause a population to be vulnerable to a hazard
- On one side of the model we have the natural hazard itself, and on the other side different factors and processes which increase a population’s vulnerability to the hazard.
- This vulnerability is often rooted in social processes
77
What are the three factors affecting vulnerability under the PAR?
- root causes are often caused by economic, demographic and/or political processes, often affecting large populations or entire countries.
- Dynamic pressures are local economic or political factors, that can affect a community or organisation
- unsafe conditions are the physical conditions that affect an individual
78
Types of root causes
Limited access to:
- power
- structures
- resources
Ideologies:
- political systems
- economic systems
79
Types of dynamic pressures
Lack of
- training
- local investment
- press freedom
Macro-forces:
- rapid population change
- rapid urbanisation
- deforestation
80
Types of unsafe conditions
- physical
- environment
- local economy
- social relations
- public actions
81
Define physical vulnerability
Individuals live in a hazard-prone area, with little protection naturally or through mitigation.
82
Define economic vulnerability
People risk losing their employment, wealth or assets during a hazard. MEDCs tend to be more economically vulnerable than LEDCs
83
Define social vulnerability
Communities are unable to support their disadvantaged or most vulnerable, leaving them at risk to hazards
84
Define knowledge vulnerability
- Individuals lack training or warning to know the risks of a hazard or how to safely evacuate.
- Alternatively, religion and beliefs may limit their understanding of hazards; hazards are an act of God, so individuals don’t mitigate or evacuate (known as fatalist belief)
85
Define environmental vulnerability
A community’s risk to a hazard is increased due to high population density in the area
86
Examples of root causes (3)
- Weak Governance
- Mismanagement by Industry, NGOs or IGOs
- High reliance on products easily affected by hazards (local agriculture near to the hazard, imports by air during a volcanic eruption)
87
Examples of dynamic pressures
- lack of training/knowledge in locals.
- rapid urbanisation
- poor communication between government and locals
- natural environment degraded (mangroves removed, rivers & channels filled with debris)
- lack of basic services (health, education, police)
88
Examples of unsafe living conditions
- lack of infrastructure (clean water, sewage removal, electricity)
- dangerous location of settlements (close to nuclear stations or the natural hazard itself)
- no warning system for locals
- disease and fire can easily spread between households
89
What does a tectonic hazard profile do?
- A hazard profile compares the physical characteristics which all hazards share.
- Hazard Profiles can help decision makers when deciding where to allocate the most human and financial resources
90
What characteristics are included in a Hazard Profile? (7)
- magnitude
- speed of onset
- areal extent
- duration
- frequency
- spatial predictability
91
How effective are hazard models?
- Hazard models are useful, but the unpredictability of hazards makes the models less effective at accurately representing human responses to hazards
92
Describe the Volcanic Explosivity Index (VEI)
● Measures the relative explosiveness of a volcanic eruption.
● Based on the height of ejected material and duration of eruption.
● Scale goes from 0-8 and is logarithmic (increase of 1 on the scale indicated a 10 times more powerful eruption).
93
Describe the Modified Mercalli Scale
● Measures the destructiveness of an earthquake.
● It is a relative scale as people would feel different amounts of shaking in different places.
● It subjective as based on if people wake up, if furniture moves, how much damaged structures receive.
● The scale varies from I to XII
I = Generally not felt by detected on seismographs
XII = Nearly total destruction
● It doesn’t consider economic, social and environmental impacts.
94
Describe the Moment Magnitude Scale
● Measures the amount of energy released in earthquake.
● Scale has no upper limit (highest recorded was 9.5)
● It's a simple measure, so environmental or social impacts must be inferred.
95
Describe the Richter Scale
● Measures the amplitude of the waves produces during an earthquake
● Most widely used scale, as it's absolute
● Must infer social or environmental impacts, which can be misleading. The highest Richter scale earthquake readings won't necessarily be the worst disasters.
● Like the VEI its scale is logarithmic.
96
What are the 4 components of the response and risk management to volcanic hazards plan?
- prevention
- preparedness
- mitigation
- adaptation
97
Describe prevention of volcanic hazards
- volcanic eruptions cannot be prevented
- only the risk to people can be prevented by not allowing people near volcanic hazards (e.g. preventing buildings around volcanoes)
98
Describe preparedness to volcanic hazards
- monitoring increases the notice of volcanic eruptions, meaning warning can be given out
- education on volcanoes in areas of risk so people know what to do
99
Describe mitigation against volcanic hazards
- direct intervention to the volcano (e.g. concrete blocks to steer lava away from areas at risk)
- strengthening buildings that are at risk of mudflows or ash pileup
- evacuation and exclusion zones
- mitigation effects on health by having emergency aid and rescue
100
Describe adaptation to volcanic hazards
- moving away from area at risk
- capitalise on opportunities, such as encouraging tourism
- change profession so it is less likely to be affected by volcanic hazards
101
What is the hazard management cycle?
The Hazard Management Cycle outlines the stages of responding to events , showing how the same stages take place after every hazard.
102
What are the four stages of the hazard management cycle?
- preparedness
- response
- recovery
- mitigation
103
Define preparedness
Being ready for an event to occur (public awareness, education, training)
104
examples of preparedness
- Developing preparation plans
- Developing warning systems
- Stockpiling medicines, food, water etc.
- Education, training, drill
105
Define response
Immediate action taken after event, the main aims would be to rescue people and reduce economic losses
106
Examples of responses
- Search and rescue efforts
- Evacuating people
- Restoring vital infrastructure like water and electricity
- Restoring vital services like law enforcement and health care
107
Define recovery
Long-term responses (restoring services, reconstruction)
108
Define recovery
Long-term responses (restoring services, reconstruction)
109
Define mitigation
Identifies the characteristics of the potential hazard and what can be done reduce their impact on people
110
Examples of mitigation
- Land use zoning
- Building codes and regulation
- Protective defences (tsunami wall)
111
How can the risk of an earthquake be predicted?
- not possible for us to predict accurately when a earthquake will happen
- risk of an earthquake can be forecast based on a statistical likelihood
- Forecasts can be based on data and evidence gathered through global seismic monitoring networks and from historical records
112
How are volcanoes predicted?
● Small earthquakes - called tremors
● Changes to the top surface of the volcano as it swells when magma builds up
● Changes to the tilt as the slope angle changes when magma builds up
113
Examples of short-term aid
- Providing aid, food, water, shelter
- Providing financial assistance so people can rebuild their livelihoods
114
Examples of long-term aid
- Rebuilding homes
- Building and repairing infrastructure
- Reopening schools and businesses
115
Name the three different approaches to managing hazards
- Modify the Event
- Modify the Vulnerability
- Modify the Loss.
116
How can events be modified on a micro scale?
Strengthening individual buildings and structures
117
How can events be modified on a macro scale?
→ Large scale support and protective measures designed to protect whole communities
118
Modifying the event - earthquakes
- Mainly micro approach
- Emphasis put into public buildings like hospitals, police stations and other vital infrastructure
- Schools and factories strengthened to help shelter people
- Some improvements to private houses
119
Modifying the event - tsunamis
- Tsunami walls which work for a given amplitude and threshold of wave
- Replanting coasts with mangroves and coastal forestry which dissipates energy from waves
120
Modifying the event - volcanoes
- Diverting flows of lava
- Reinforce house roofs to withstand large deposits of ash
121
Examples of modifying the event (4)
- land use zoning
- resistant buildings
- tsunami defences
- lava diversion
122
Describe land use zoning
Preventing building on low lying areas and areas of high risk
123
Advantages of land use zoning
- low cost
- reduces vulnerability
124
Disadvantages of land use zoning
- Stops economic development on some high value land
- Strict enforcement required
125
Define resistant buildings
Buildings with deep foundations, sloped roofs so that ash doesn’t build and create pressure
126
Advantages of resistant buildings
- Can help prevent collapsing
- Protects people and property
127
Disadvantages of resistant buildings
- High cost for larger buildings
- Low income families cannot afford this
128
Describe tsunami defence
Sea walls which stop waves travelling inland
129
Advantages of tsunami defences
- Reduces damage
- Provides security
130
Disadvantages of tsunami defences
- Very high cost
- Doesn’t look nice
- Can be overtopped
131
Describe lava diversion
Barriers and water cooling to divert and slow down lava flow
132
advantages of lava diversion
- Diverts lava away
- Low cost
133
Disadvantages of lava diversion
Only works for low VEI lava
134
Examples of modifying the vulnerability (3)
- hi tech scientific monitoring
- community preparedness and education
- adaptation
135
advantages of Hi Tech Scientific Monitoring
- Predicting eruption is possible in some cases
- Warning and evacuation can help save lives
136
Disadvantages of hi tech scientific monitoring
- Costly, in LDCs, volcanoes aren’t usually monitored
- Doesn’t prevent property damage
137
Advantages of community preparedness and education
- Low cost and often implemented by NGOs
- can save lives through small actions
138
Disadvantages of community preparedness and education
- Doesn’t prevent property damage
- Harder to implement in isolated rural areas
139
Advantages of adaptation
- Helps save lives and property
140
Disadvantages of adaptation
- High population densities prevent it
- Disrupts people’s traditional home and traditions
141
Modifying the loss examples (3)
- short term aid
- long term aid
- insurance
142
Advantages of short term aid
- Can help reduce death toll by saving lived and keeping people alive until long term aid is provided
143
Disadvantages of short term aid
- High costs and technical difficulties in isolated areas
- Emergency services are limited and are poorly equipped in LDC
144
Advantages of long term aid
- Reconstruction can help improve resilience through
land use planning and better construction methods
145
Disadvantages of long term aid
- Very high costs
- Needs are quickly forgotten by the media shortly are the disaster
146
Advantages of insurance
- Allows people to recover economically for paying reconstruction
147
Disadvantages of insurance
- Doesn’t help save lives
- Not many in LDCs have insurance
148
Describe the role of communities in modifying losses
In remote and isolated areas, it may take a long time for aid to come and people may begin local recovery operations, communities may clear debris from roads and set up temporary shelters.
149
Describe the roles of NGOs and TNCs in modifying losses
- NGOs play a very important role from providing funds, coordination rescue efforts and helping to develop reconstruction plans.
- Occasionally, TNCs and NGOs may cooperate; Charity buckets or events may be organised by businesses to improve NGOs ability to help.
150
Why might less developed countries be more vulnerable to hazards?
- Governments of developing countries may not prioritise investing money in hazard mitigation as they tend to focus their resources on development and economic growth.
- This lack of investment in hazard management often means that less developed countries and
their populations are more vulnerable to hazards.
151
Human factors contributing to a population's vulnerability (4)
- unstable political governance and/or corruption
- population density
- geographical isolation and accessibility
- level of urbanisation
152
How might unstable political governance and/or corruption increase vulnerability?
a lack of political cohesion can impact on how prepared a country is for a hazard and can also negatively impact response and recovery efforts after the event.
153
How might population density increase vulnerability?
the higher the population density the more people affected by a hazard.
154
How might geographical isolation and accessibility increase vulnerability?
remote, rural areas often have poor transport links which can negatively effect rescue efforts.
155
How might levels of urbanisation increase vulnerability?
urban areas tend to be worse affected by hazards due to two factors:
- urban areas are densely populated
- they have larger amounts of infrastructure meaning there is more economic damage.
156
Factors caused by governance that increase vulnerability (4)
- meeting basic needs
- planning
- preparedness
- corruption
157
Describe how meeting basic needs affects vulnerability
When food supply, water supply and health needs are met, the population is generally less vulnerable to secondary hazards such as diseases.
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Describe how land-use planning affects vulnerability
Land-use planning can reduce risk by preventing people living in areas of high risk. Secondary hazards may be made worse by deforestation
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Describe how preparedness affects vulnerability
Education and community preparation programmes raise awareness and teach people how to prepare, evacuate and act when a disaster strikes.
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Describe how corruption affects vulnerability
- If government politicians accept bribes and do unethical things, then vulnerability would increase as money may not be invested in crucial areas like emergency services.
161
What are the characteristics of tectonic mega-disasters?
▪ Large scale disaster affecting a large spatial areas or large population.
▪ They pose problems in effective management to minimise the impacts.
▪ The scale of the impact may require international support and aid.
▪ Mega Disasters are low probability (rare).
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Global impact of mega-disasters
- The globalisation of production and supply chains has allowed international businesses to reduce the costs and become more efficient.
- However, mega-disasters significantly damage globalised businesses
- e.g. Tohoku 2011, Eyjafjallajokull 2010
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Benioff zone
A region of the subducting plate, most affected by pressure and friction, where most destructive margin earthquakes originate.
