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edexcel a level geography > 1 - tectonic processes & hazards > Flashcards

1 - tectonic processes & hazards Flashcards

1
Q

THE GLOBAL DISTRIBUTION OF HAZARDS - what is meant by a hazard?

A
  • a hazard is a potential threat to human life and property
  • a natural hazards can either be hydro-meteorological (caused by climatic processes) or geophysical (caused by land processes)
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2
Q

where do geophysical hazards occur?

A
  • near plate boundaries
  • plates move at different speeds and directions which can cause collisions, earthquakes and volcanic activity
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3
Q

what are intra-plate earthquakes?

A
  • earthquakes which occur near the middle of plates
  • causes of this not fully understood BUT is assumed that plates have pre-existing weaknesses which become reactivated, forming seismic waves
  • EXAMPLE : an intra-plate earthquake may occur if solid crust, which has weakened over time, cracks under pressure
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4
Q

what are volcanic hotspots?

A
  • volcanic hotspots, such as the Ring of Fire, are also situated amongst the centre of plates
  • this is a localised area of the lithosphere (Earth’s crust and upper mantle), which has an unusually high temperature due to the upwelling of hot molten material from the core
  • (first theorised by Tuzo Wilson in 1963)
  • at hotspots, such as the Hawaii hotspot, magma rises as plumes (hot rock)
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5
Q

where do the most powerful earthquakes occur?

A
  • usually at convergent or conservative boundaries
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6
Q

what is an OFZ and a CFZ?

A
  • OFZ (oceanic fracture zone) : a belt of activity through the oceans and along the mid-ocean ridges through Africa, the Red Sea and the Dead Sea
  • CFZ (continental fracture zone) : a belt of activity along the mountain ranges from Spain through the Alps to the Middle East and to the Himalayas
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7
Q

describe tectonic trends since 1960

A
  • total number of recorded hazards has increased
  • number of fatalities has decreased, but are some spikes during mega disasters
  • total number of people being affected is increasing, due to population growth
  • economic costs associated with hazards and disasters has increased significantly —> partly due to increases in development as infrastructure in more developed countries costs more to repair. also, increasing number of insurance policies, especially in developed countries, heightens cost
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8
Q

why is reporting disaster impacts (eg fatalities) considered difficult and controversial? (1)

A
  • depends on whether you look at the direct deaths so those killed in the disaster straight away or indirectly by looking at how many people died of diseases that spread after the disaster. some impacts take time to become apparent.
  • location is important as rural and isolated areas are hard to reach and so it may be hard to collect data from them. similarly, data may be difficult to collect in areas with very high population densities
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9
Q

why is reporting disaster impacts (eg fatalities) considered very difficult and controversial? (2)

A
  • different methods may be used by different organisations so as a result different sources may quote different numbers of deaths and injuries
  • the number of deaths quoted by a government could be subject to bias.
  • EXAMPLE : during 2004 Indian Ocean tsunami, the Burmese government claimed there was 0 deaths in Burma. this may be to try and show that the government is doing a good job in terms of aid, protection etc.
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10
Q

TECTONIC THEORY - name the 4 sections of the Earth

A
  • crust
  • mantle
  • outer core
  • inner core
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11
Q

describe the features of the crust

A
  • also known as the lithosphere
  • uppermost layer of the Earth which is the thinnest, least dense and lightest
  • OCEANIC CRUST : only 7km thick (thin), relatively young, denser
  • CONTINENTAL CRUST : can be up to 70km thick (thicker), less dense, much older
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12
Q

describe the features of the mantle

A
  • may also be called the asthenosphere
  • largely composed of silicate rocks, rich in iron and magnesium
  • is semi-molten and a temperature gradient (towards the core) generates convection currents
  • this causes the circulation of the mantle, may contribute to the lithosphere’s plate tectonic movement
  • is at a depth from 700km to 2890 km below the crust
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13
Q

describe the features of the outer core

A
  • dense, semi-molten rocks containing iron and nickel alloys
  • at a depth of 2890km to 5150km below the Earth’s surface
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14
Q

describe the features of the inner core

A
  • similar composition to the outer core
  • over 5150 km below the Earth’s crust
  • solid due to extreme pressures it experiences
  • core’s high temperature is a result of : primordial heat left over from Earth’s formation, radiogenic heat produced from radioactive decay
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15
Q

what happens at plate boundaries?

A
  • different plates can either move towards each other (destructive plate margin)
  • can move away from each other (constructive plate margin)
  • can move parallel to each other (conservative plate margin)
  • different landforms are created in these different interactions
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16
Q

name the landform/process created at conservative boundaries

A
  • earthquakes
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17
Q

name the landform/process created at constructive plate boundaries

A
  • continental/continental —> rift valleys, earthquakes, volcanoes
  • oceanic/oceanic —> ocean ridges, earthquakes, volcanoes
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18
Q

name the landform/process created at destructive plate boundaries

A
  • continental/continental —> fold mountains, earthquakes
  • oceanic/oceanic —> ocean trenches, island arcs, earthquakes, volcanoes
  • continental/oceanic —> volcanoes, fold mountains, earthquakes
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19
Q

DESTRUCTIVE - what happens at a destructive plate boundary with continental and oceanic crust?

A
  • denser oceanic plate subducts below the continental
  • plate subducting leaves a deep ocean trench
  • oceanic crust is melted as it subducts into the asthenosphere
  • extra magma created causes pressure to build up
  • pressurised magma forces through weak areas in continental plate
  • explosive, high pressure volcanoes erupt through continental plate, known as composite volcanoes
  • fold mountains occur when sediment is pushed upwards during subduction
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20
Q

DESTRUCTIVE - what happens at a destructive plate boundary with oceanic and oceanic crust?

A
  • heavier plate subducts leaving an ocean trench
  • fold mountains will also occur
  • built up pressure causes underwater volcanoes bursting through oceanic plate
  • lava cools and creates new land called island arcs
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21
Q

DESTRUCTIVE - what happens at a destructive plate boundary with continental and continental crust?

A
  • both plates are not as dense as oceanic so lots of pressure builds
  • ancient oceanic crust is subducted slightly, but 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
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22
Q

CONSTRUCTIVE - what happens at a constructive plate boundary with oceanic and oceanic crust?

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 floor spreads and gets wider)
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23
Q

what is sea floor spreading?

A
  • when new land is formed on the ocean floor by lava filling the gaps
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24
Q

how has seafloor spreading provided evidence to prove plate movement?

A
  • PALEOMAGNETISM : study of rocks that show the magnetic fields of the Earth
  • as new rock is formed and cools, the magnetic grains within the rock align with the magnetic poles
  • our poles (N,S) switch periodically —> each time these switch the new rocks being formed at plate boundaries align in the opposite direction to the older rock
  • on ocean floor either side of constructive plate boundaries, geologists observed there are symmetrical bands of rock with alternating bands of magnetic polarity
  • this is evidence of seafloor spreading
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25
Q

CONSTRUCTIVE - what happens at a constructive plate boundary with continental and continental crust?

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, separate completely from the main island
  • lifted areas of rocks are known as horsts whereas the valley itself is known as a graben
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26
Q

what are the further forces influencing how convergent boundaries occur? (1)

A
  • RIDGE PUSH : 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 (as this movement is influenced by gravity, it is known as gravitational sliding)
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27
Q

what are the further forces influencing how convergent boundaries occur?

A
  • SLAB PULL : when a plate subducts, the plate sinking into the mantle pulls the rest of the plate (slab) with it, causing further subduction
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28
Q

CONSERVATIVE - what happens at a conservative plate boundary?

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
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29
Q

PLATE MOVEMENTS : what are the two different types of crust and what rocks do they consist of?

A
  • OCEANIC & CONTINENTAL
  • OCEANIC : low density of rock, mainly basalt, thin, newly created
  • CONTINENTAL : high density of rock, mainly granite, thick, old
  • the density of the plate will determine whether the plate subducts or is forced upwards
  • this will determine the landscape and hazards the margin is vulnerable to
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30
Q

describe the different mechanisms that could cause plate movement (1)

A
  • 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 and becomes more dense, begins to sink back down to the core
  • these are convection currents, which push the plates
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31
Q

describe the different mechanisms that could cause plate movement (2)

A
  • SLAB PULL : old oceanic crust (most dense plate) will submerge into the mantle
  • this pulling action drags the rest of the plate with it
  • (first theorised by Dan McKenzie)
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32
Q

what are researchers’ current thoughts about tectonic movement?

A
  • previously, convection currents were thought to be the primary cause of plate movement
  • however, researchers now believe slab pull is the primary mechanism for plate movement
  • convection currents seem too weak to move massively dense plates
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33
Q

EARTHQUAKES - why don’t plates move in fluid motion?

A
  • plates do not fit perfectly
  • at all boundaries, plates can become stuck due to the friction between plates
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34
Q

what happens when plates get stuck?

A
  • the convection currents in the asthenosphere continue to push, which builds the pressure
  • builds up so much that it cannot be sustained, the plates eventually give way
  • all of the pressure is released in a sudden movement, causing a jolting motion in the plates
  • jolt is responsible for seismic movement spreading throughout the ground in the form of seismic waves (or shock waves)
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35
Q

state the difference between the focus and the epicentre of an earthquake

A
  • the focus (or hypocentre) is the point underground where the earthquake originates from
  • the epicentre is the area above ground that is directly above the focus
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36
Q

name the four different types of seismic waves

A
  • primary waves
  • secondary waves
  • love waves
  • rayleigh waves
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37
Q

what are the characteristics of primary & secondary waves?

A
  • PRIMARY : travel through solids, compressional, vibrate in the direction of travel, travel at 4-8km/s
  • SECONDARY : vibrate at right angles to direction of travel, travel only through solid rocks, travel at 2.5-4km/hr
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38
Q

what are the characteristics of love and rayleigh waves?

A
  • LOVE : near to ground surface, rolling motion producing vertical ground movement, travel at 2-6km/hr
  • RAYLEIGH : vertical and horizontal displacement, travel at 1-5km/hr, compressional
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39
Q

why are secondary and love waves the most destructive?

A
  • 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
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40
Q

what happens to intensity of waves as you go further from the epicentre?

A
  • will decrease further from the epicentre, as waves lose energy as they travel
  • HOWEVER, this doesn’t mean impacts felt or damage caused will always decrease further from the epicentre as other factors affect a location’s vulnerability : geology, geographical location, mitigation etc.
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41
Q

SECONDARY HAZARDS OF EARTHQUAKES - what is soil liquefaction?

A
  • affects poorly compacted sand and silt
  • water moisture within the soil separates from the soil particles, rises to the surface
  • this can cause the soil to behave like a liquid, which can cause building subsidence or landslides
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42
Q

what are landslides?

A
  • 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
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43
Q

TSUNAMIS - how does a tsunami occur?

A
  • when an oceanic crust is jolted during an earthquake, all of the water above this plate is displaced, normally upwards
  • 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 (height)
  • as it gets closer to the coast, the sea level decreases so there is friction between the sea bed and the waves
  • this causes the waves to slow down and gain height, creating a wall of water that is on average 10ft high, but can reach 100 ft
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44
Q

where are tsunamis generated?

A
  • generally generated in subduction zones at convergent plate margins
    -most tsunamis found along Pacific Ring of Fire, hence the most vulnerable countries are often located in Asia or Oceania
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45
Q

list some human and physical factors the impact of a tsunami depends on

A
  • population density of area hit
  • coastal defences
  • duration of the event
  • wave amplitude & distance travelled
  • warning and evacuation systems
  • level of economic and human development
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46
Q

VOLCANOES - name the primary hazards caused by volcanoes

A

primary hazards are caused directly from the volcano, tend to have a fast speed of onset
- lava flows
- pyroclastic flows
- tephra and ash flows
- volcanic gases

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47
Q

what are lava flows and pyroclastic flows?

A
  • LAVA FLOWS : streams of lava that have erupted onto the Earth’s surface. fast flowing lava can be very dangerous which depends on the lava’s viscosity (the explosivity and viscosity depend on silicon dioxide content)
  • 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, pyroclastic flows are extremely dangerous and can cause asphyxiation for anyone unfortunately caught by the flow
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48
Q

what are tephra/ash flows and volcanic gases?

A
  • TEPHRA & 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
  • VOLCANIC GASES : gases like sulphur dioxide and carbon monoxide are released into the atmosphere. due to their potency, volcanic gases can travel long distances
49
Q

why do secondary hazards occur after an eruption and name some examples

A
  • occur as a result of the heat produced by the volcano
  • lahars
  • jokulhlaup
  • acid rain
50
Q

what are lahars?

A
  • 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
51
Q

what is a jokulhlaup?

A
  • when snow and ice in glaciers melt after an eruption which causes sudden floods that are very dangerous
52
Q

what is acid rain?

A
  • caused when gases such as sulphur dioxide are released into the atmosphere
53
Q

CLASSIFICATION & THEORIES OF TECTONIC EVENTS - what is a disaster?

A
  • a serious disruption of the functioning of a community or society involving human, material, economic and environmental losses
  • exceeds the ability of the affected community or society to cope using its own resources
54
Q

state the equation used to calculate risk

A
  • the risk a community faces from a natural hazard can be calculated from the equation :

risk(R) = hazard(H) * vulnerability(V) / capacity to cope (C)

55
Q

state the factors why an area might be at high risk

A
  • how developed a country is significantly affects how resilient its population is and their capacity to cope with a hazard
  • their capacity to cope is low
  • they are quite vulnerable
  • the hazard is large/high intensity
56
Q

DEGG’S MODEL - what is the model a representation of?

A
  • hazards should not be confused with natural disasters
  • a disaster will only occur when a vulnerable population (one that will be significantly disrupted and damaged) is exposed to a hazard
  • degg’s model represents this concept
  • if the population is not vulnerable, the hazard will not have a significant effect, thus the event will not be disastrous
57
Q

what does the UNISDR (United Nations Office for Disaster Risk Reduction) define a disaster as?

A
  • ‘a serious disruption of the functioning of a community or society involving widespread losses and impacts, which exceeds the ability of the affected community or society to cope with using its own resources’
58
Q

describe the other ways to classify a tectonic hazard

A
  • the volume of people affected : the International Disaster Database classifies a disaster as an event where more than 100 people are affected or more than 10 die
  • economic cost of the disaster : jobs lost, cost of repairs needed, economic productivity lost.
  • could compare a tectonic disaster to previous events, prediction models or average statistics for that location. some events may be more severe than the average tectonic hazard, due to a series of factors coinciding
59
Q

THE PARK MODEL - what does it represent?

A
  • 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
  • steepness of curve : shows how quickly an area deteriorates and recovers
  • depth of curve : shows the scale of the disaster (eg lower the curve, lower the quality of life)
60
Q

describe stage 1 of the model

A
  • relief (hours—>days)
  • immediate local response : medical aid, search and rescue
  • immediate appeal for foreign aid : the beginnings of global response
61
Q

describe stage 2 of the model

A
  • rehabilitation (days—>weeks)
  • services begin to be restored
  • temporary shelters and hospitals set up
  • food and water distributed
  • coordinated foreign aid : peacekeeping forces etc.
62
Q

describe stage 3 of the model

A
  • reconstruction (weeks—>years)
  • 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
63
Q

how does the model work as a control line to compare hazards?

A
  • an extremely catastrophic hazard would have a steeper curve than the average and would have a slower recovery time than the average, for example
64
Q

THE PRESSURE AND RELEASE MODEL (PAR) - what is it used for?

A
  • used to analyse factors which cause a population to be vulnerable to a hazard
  • on one side : natural hazard itself, on the other side : different factors and processes which increase a population’s vulnerability to the hazard
  • vulnerability is often rooted in social processes
  • these are dynamic and ever changing, are often unrelated to the hazard itself eg poverty, poor governance
65
Q

why is the PAR model considered a complex model?

A
  • no two hazards are the same, factors leading to vulnerability are interconnected and hard to measure
  • if we reduce social factors affecting a population, we can reduce the pressure they face and so reduce their vulnerability and the effect of natural hazards
66
Q

describe the three sections progress of vulnerability is split into

A
  • root causes : often caused by economic, demographic and/or political processes ; often affecting large populations or entire countries
  • dynamic pressures : local economic or political factors that can affect a community or organisation
  • unsafe conditions : the physical conditions that affect an individual (unsafe building, low income, poor health etc.)
67
Q

name the different ways vulnerability can be defined

A

depends on who or what is affected
- physical vulnerability
- economic vulnerability
- social vulnerability
- knowledge vulnerability
- environmental vulnerability

68
Q

describe physical, economic and social vulnerability

A
  • PHYSICAL : individuals live in a hazard-prone area, with little protection naturally or through mitigation
  • ECONOMIC : people risk losing their employment, wealth or assets during a hazard, MEDCs tend to be more economically vulnerable than LEDCs
  • SOCIAL : communities are unable to support their disadvantaged or most vulnerable, leaving them at risk to hazards
69
Q

describe knowledge and environmental vulnerability

A
  • KNOWLEDGE : individuals lack training or warning to know the risks of a hazard or how to evacuate safely. alternatively, religion and beliefs may limit their understanding or hazards ; hazards are an act of God, so individuals don’t mitigate or evacuate (known as fatalist belief)
  • ENVIRONMENTAL : a community’s risk to a hazard is increased due to high population density in the area
70
Q

give an example to support the idea that the PAR model suggests a series of factors lead to a population’s vulnerability

A
  • a lack of infrastructure (eg poor sewage management) can worsen the impacts of a hazard, since it is harder to maintain clean living conditions, avoid the spread of disease following a disaster. a lack of infrastructure would be a factor of UNSAFE LIVING CONDITIONS
  • however, the lack of infrastructure may be due to rapid urbanisation, where little planning has been taken to carefully construct houses and infrastructure to cope with the rising population. rapid urbanisation would be the DYNAMIC PRESSURE
  • ultimately, planning and controlling safe population growth is the government’s responsibility. so the ROOT CAUSE of this disaster may be weak governance
71
Q

list some common factors that can affect the vulnerability of a society (ROOT CAUSES)

A
  • 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)
72
Q

list some common factors that can affect the vulnerability of a society (DYNAMIC PRESSURES)

A
  • lack of knowledge/training in locals
  • rapid urbanisation
  • poor communication between government and locals
  • natural environment degraded (mangroves removed, rivers & channels filled with debris)
  • lack of basis services (health, education, police)
73
Q

list some common factors that can affect the vulnerability of a society (UNSAFE LIVING CONDITIONS)

A
  • 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 spread easily between households
74
Q

what are tectonic hazard profiles and why are they useful?

A
  • hazard profile compares the physical characteristics which all hazards share
  • can help decision makers when deciding where to allocate the most human and financial resources
75
Q

describe the characteristics of a hazard profile

A
  • frequency : how often it happens
  • magnitude : how extensive an area the event could affect
  • duration : how long the event lasts
  • speed of onset : how much warning time before event occurs
  • fatalities : number of deaths caused
  • economic loss : value of assets damaged, lack of industry or economic productivity, insurance policies
  • spatial predictability : the predictability of where would be affected
76
Q

EVALUATING EFFECTIVENESS OF MODELS - why is there uncertainty surrounding the use of hazard models?

A
  • hazard models are useful BUT the unpredictability of hazards makes the models less effective at accurately representing human responses to hazards
77
Q

what are some questions that can be asked when evaluating how effective models are?

A
  • can they be applied to every hazard? are some hazards more complicated and require a complex model?
  • is there any timeframe? do the models accurately lay out the time taken for a full response and how this changes due to aspects of the hazard such as intensity?
  • does the model take any aspects of the hazards into account such as level of development?
78
Q

MEASURING TECTONIC EVENTS - describe the volcanic explosivity index (VEI)

A
  • 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 indicates a 10 time more powerful eruption)
79
Q

describe the modified mercalli scale

A
  • measures the destructiveness of an earthquake
  • is a relative scale as people would feel different amounts of shaking in different places
  • is subjective as based on if people wake up, if furniture moves, how much damage structures receive
  • scale varies from I to XII
  • I : generally not felt by detected on seismographs
    XII : nearly total destruction
  • doesn’t consider economic, social and environmental impacts
80
Q

describe the moment magnitude scale

A
  • measures the amount of energy released in an earthquake
  • scale from 0-9
  • is a simple measure, so environmental or social impacts must be inferred
81
Q

describe the richter scale

A
  • measures the amplitude of the waves produced 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
82
Q

MANAGING TECTONIC HAZARDS - how can hazards be responded to?

A
  • preventing them directly
  • being prepared for the next hazard
  • mitigating the effects
  • completely adapting your lifestyle to limit the hazard’s effects
83
Q

describe how prevention can be a response to volcanic hazards

A
  • volcanic eruptions cannot be prevented
  • only the risk to people can be prevented by not allowing people near volcanic hazards
  • EXAMPLE : preventing building around volcanoes
84
Q

describe how being prepared can be a response to volcanic hazards

A
  • monitoring increases the notice of volcanic eruptions, meaning warnings can be given out
  • education on volcanoes in areas of risk so people know what to do if there is a volcanic eruption
  • evacuation procedures planned
  • training response teams
85
Q

describe how mitigation can be a response to volcanic hazards

A
  • 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
  • mitigating effects on health by having emergency aid and rescue
86
Q

describe how adaptation can be a response to volcanic hazards

A
  • move away from areas at risk
  • capitalise on the opportunities, such as encouraging tourism
  • change profession so it is less likely to be affected by volcanic hazards
87
Q

HAZARD MANAGEMENT CYCLE - what does it outline?

A
  • outlines the stages of responding to events, showing how the same stages take place after every hazard
88
Q

describe the four stages of the hazard management cycle

A
  • PREPAREDNESS : being ready for an event to occur (public awareness, education, training)
  • RESPONSE : immediate action taken after the event (evacuation, medical assistance, rescue)
  • RECOVERY : long-term responses (restoring services, reconstruction)
  • MITIGATION : strategies to lessen effects of another hazard (barriers, warning signals developed, observatories)
89
Q

how, if possible, can earthquakes be monitored and predicted?

A
  • it is not possible to predict accurately when an earthquake will happen
  • instead, the 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 also from historical records
90
Q

how can scientists predict volcanic eruptions?

A
  • can sometimes predict volcanic eruptions with some degree of accuracy
  • can use special equipment to monitor volcanoes, detect signs of imminent eruption :
  • 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
91
Q

define mitigation and state some examples of how hazards can be mitigated

A

identifies the characteristics of the potential hazard and what can be done to reduce their impact on people, such as :
- land use zoning
- building codes and regulation
- protective defences (tsunami wall)

92
Q

define preparedness and state some examples of how hazards can be prepared for

A

minimising the loss of life and property
- developing preparation plans
- developing warning systems
- stockpiling medicines, food, water etc
- education, training, drill

93
Q

define response and state some examples of responses to hazards

A

coping with a disaster, the main aims would be to rescue people and reduce economic losses
- search and rescue efforts
- evacuating people
- restoring vital infrastructure like water and electricity
- restoring vital services like law enforcement and health care

94
Q

describe the role of local aid and International aid

A

focuses on short-term and long-term recovery
short-term :
- providing id, food, water, shelter
- providing financial assistance so people can rebuild their livelihoods
long-term:
- rebuilding homes
- building and repairing infrastructure
- reopening schools and businesses

95
Q

MANAGEMENT APPROACHES - name the three different approaches to managing a tectonic hazard

A
  • modify the event
  • modify the vulnerability
  • modify the loss
96
Q

how can the event be modified?

A
  • can control the design of buildings through civil engineering using micro and macro methods
    MICRO —> strengthening individual buildings and structures
    MACRO —> large scale support and protective measures designed to protect whole communities
97
Q

how can an earthquake event be modified?

A
  • 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
98
Q

how can a tsunami event be modified?

A
  • tsunami walls which work for a given amplitude and threshold of wave
  • replanting coasts with mangroves and coastal forestry which dissipates energy from waves
99
Q

how can a volcano event be modified?

A
  • diverting flows of lava
  • reinforce house roofs to withstand large deposits of ash
100
Q

describe land use zoning and its advantages and disadvantages

A

LAND USE ZONING - preventing building on low lying areas and areas of high risk
ADVANTAGES - low cost, reduces vulnerability
DISADVANTAGES - stops economic development on some high value land, strict enforcement required

101
Q

describe the use of resistant buildings and its advantages and disadvantages

A

RESISTANT BUILDINGS - buildings with deep foundations, sloped roofs so that ash doesn’t build and create pressure
ADVANTAGES - can help prevent collapsing, protects people and property
DISADVANTAGES - high cost for larger buildings, low income families can’t afford this

102
Q

describe the use of lava diversion and its advantages and disadvantages

A

LAVA DIVERSION - barriers and water cooling to divert and slow down lava flow
ADVANTAGES - diverts lava away, low cost
DISADVANTAGES - only works for low VEI lava

103
Q

list the different ways you can modify the vulnerability

A
  • hi-tech scientific monitoring
  • community preparedness and education
  • adaptation
104
Q

describe hi-tech scientific monitoring and its advantages/disadvantages

A

HI-TECH SCIENTIFICMONITORING - monitors volcano behaviour and predict eruptions.
ADVANTAGES - predicting eruption is possible in some cases, warning and evacuation can help save some lives
DISADVANTAGES - costly, in LDCs, volcanoes aren’t usually monitored, doesn’t prevent property damage

105
Q

what are the advantages and disadvantages of community preparedness and education?

A

ADVANTAGES - low cost, often implemented by NGOs ; can save lives through small actions
DISADVANTAGES - doesn’t prevent property damage, harder to implement in isolated rural areas

106
Q

describe adaptation and its advantages/disadvantages

A

ADAPTATION - moving out of harm’s way and relocation
ADVANTAGES - helps save lives and property
DISADVANTAGES - high population densities prevent it, disrupts people’s traditional home and traditions

107
Q

list the ways to modify the loss

A
  • short term aid
  • long term aid
  • insurance
108
Q

describe short term aid and its advantages/disadvantages

A

SHORT TERM AID - search and rescue, also food, water, aid and shelter
ADVANTAGES - can help reduce death toll by saving lives and keeping people alive until long term aid is provided
DISADVANTAGES - high costs and technical difficulties in isolated areas, emergency services are limited and are poorly equipped in LDCs

109
Q

describe long term aid and its advantages/disadvantages

A

LONG TERM AID - reconstruction plan to rebuild an area and improve resilience
ADVANTAGES - reconstruction can help improve resilience through land use planning and better construction methods
DISADVANTAGES - very high costs, needs are quickly forgotten by the media shortly after the disaster

110
Q

describe insurance and its advantages/disadvantages

A

INSURANCE - compensation to replace losses
ADVANTAGES - allows people to recover economically for paying reconstruction
DISADVANTAGES - doesn’t help save lives, not many in LDCs have insurance

111
Q

describe the role of communities in response to the event

A
  • 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
112
Q

describe the role of NGOs and TNCs in response to the event

A
  • NGOs play a very important role from providing funds, coordinating 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 IGOs ability to help
113
Q

why may less developed countries be more vulnerable to hazards?

A
  • governments of developing countries may not prioritise investing money in hazard mitigation as they tend to focus their resources on development and economic growth
114
Q

what does the Risk Poverty Nexus state about poverty in regard to natural hazards?

A
  • states that poverty is both a contributing factor and consequence of a natural hazard
  • also suggests that a positive feedback mechanism can cause further economic loss for already poor countries
115
Q

describe the different inequalities affecting a community’s resilience to a hazard

A
  • asset inequality : relates to housing and security of tenure, also agricultural productivity
  • political inequality : where certain groups of people, usually wealthy and elite, hold quite a lot of power, political influence
  • social status inequality : often directly linked to space and has a bearing on other dimensions of inequality, including the ability of individuals and groups to secure regular income and access services
  • entitlement inequality : refers to unequal access to public services and welfare systems as well as inequalities in the application of the rule of law
116
Q

HAZARD VULNERABILITY - describe the factors that can contribute to a population’s vulnerability

A

—> unstable political governance and/or corruption : a lack of political cohesion can impact on how prepared a country is for a hazard, can also negatively impact response and recovery efforts after the event
—> population density : the higher the population density the more people affected by a hazard
—> level of urbanisation : urban areas tend to be worse affected by hazard due to two factors ; urban areas are densely populated and also have larger amounts of infrastructure meaning there is more economic damage
—> geographical isolation and accessibility : remote, rural areas often have poor transport links which can negatively affect rescue effort

117
Q

GOVERNANCE - what factors affect how well a government is able to respond to an event?

A
  • MEETING BASIC NEEDS : when food supply, water supply and health needs are met, the population is generally less vulnerable to secondary hazards such as disease
  • PLANNING : land-use planning can reduce risk by preventing people living in areas of high risk. secondary hazards may be made worse by deforestation
  • PREPAREDNESS : education and community preparation programmes raise awareness, teach people how to prepare, evacuate and act when disaster strikes
  • CORRUPTION : if gov politicians accept bribes and do unethical things, then vulnerability would increase as money would be invested in crucial areas like emergency services
118
Q

TECTONIC MEGA DISASTERS - what are the characteristics?

A
  • large scale disaster affecting a large spatial area 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)
119
Q

give an example of how mega-disasters have caused business disruption

A

the globalisation of production and supply chain has allowed international businesses to reduce costs, become more efficient . however, mega-disasters significantly damage globalised businesses
- EXAMPLE : 2011 Tohoku earthquake and tsunami —> there was a knock on effect for TNCs such as Toyota and BMW which operate and source products from Japan.
- this lost potential revenue for those TNCs and caused general economic uncertainty

edexcel a level geography (4 decks)

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