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1 Tectonic Processes and Hazards > EQ2 - Why do some tectonic hazards develop into disasters? > Flashcards

EQ2 - Why do some tectonic hazards develop into disasters? Flashcards

1
Q

What are the 2 factors which MUST intersect in the Degg Model, to cause a disaster?

A
  1. The presence of a natural hazard (e.g Volcano)

AND

  1. A vulnerable population

Both of these must be present for a disaster to occur

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2
Q

What factors should be considered when understanding risk?

A
  1. Unpredictability of events
  2. Lack of alternatives to the area (e.g occupational immobility)
  3. Dynamic Hazards (level of threat can increase/decrease over time)
  4. Cost-benefit of living in a hazardous area
  5. ‘Russian Roulette Reaction’ (accepting risk - fatalism)
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3
Q

What is the hazard-risk formula?

A

Risk = hazard x exposure x vulnerability/manageability

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4
Q

Loosely, what is the concept of Resilience?

A

The ability to ‘spring back’ from a hazard event or disaster shock

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5
Q

What 2 processes form the basis for the Pressure and Release (PAR) model?

A

Vulnerability

Natural Hazards

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6
Q

What does the creator compare his PAR model to - with the pressures of vulnerability and natural hazards pushing inward to create a disaster

A

A nutcracker

  • this pressure can only be relieved by reducing vulnerability
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7
Q

What 3 components make up progression of vulnerability (PAR) ?

A

Root Causes&raquo_space;> Dynamic Pressures&raquo_space;> Unsafe conditions

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8
Q

What 3 strategies may be used by resilient communities to limit the affects of a natural disaster?

A
  1. Emergency evacuation, rescue and relief systems already in place
  2. Hazard-resistant building design
  3. Land-use planning to reduce populations in hazard areas
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9
Q

What is ‘capacity to cope’ with a natural hazard otherwise known as?

A

Resilience

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10
Q

What is a natural hazard?

A

Natural events that have the POTENTIAL to harm people and their property

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11
Q

What is a natural disaster, compared to a natural hazard?

A

A natural disaster is the realisation of the hazard - i.e harm has occurred

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12
Q

What do large insurers define the threshold for a natural disaster?

A

Where economic losses of over $1.5m are experienced

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13
Q

What demographic factor most affects resilience?

A

Age

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14
Q

What % of 60+ people live in less-developed regions?

A

66% - expected to rise to 79% by 2050

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15
Q

What % of those who died in the 2011 Japan tsunami wee 65+?

A

56%

  • although the 65+ demographic did comprise 1/4 of the population in the affected area
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16
Q

What part of the PAR model are these vulnerability factors a part of:

Low access to resources

Poor governance

Weak economic system

A

Root causes

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17
Q

What part of the PAR model are these vulnerability factors a part of:

Lack of education

Rapid population change and urbanisation

A

Dynamic pressures

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18
Q

What part of the PAR model are these vulnerability factors a part of:

Poor construction standards

Poverty

Unsafe infrastructure

A

Unsafe conditions

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19
Q

In Haiti, what were 2 of the main Root Causes of the disaster?

A

GDP per capita of $350
50% of the population under 20 years old

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20
Q

In Haiti, what were 2 of the main dynamic pressures which caused the disaster?

A

Lack of disaster education
Rapid urbanisation

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21
Q

In Haiti, what were 2 of of the main unsafe conditions which caused the disaster?

A

80% unplanned (informal) housing in Port-au-Prince
25% of population live in extreme poverty

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22
Q

What are the 3 broad main impacts of tectonic hazards?

A

Social, economic and environment

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23
Q

In the last 30 years, which tectonic hazard has had a small and declining impact, especially on death tolls?

A

Volcanoes

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24
Q

In the last 30 years, which tectonic hazard has had large impacts, with high-magnitude events being common?

A

Earthquakes

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25
Q

In the last 30 years, which tectonic hazard has been relatively infrequent, but has had very large impacts? (e.g Indian Ocean 2004)

A

Tsunami’s

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26
Q

Generally, economic costs in developed and emerging countries are often low as their is very little infrastructure.

True or False?

A

False - costs are often enormous and require large aid sums from developed nations

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27
Q

Death tolls in developed countries are generally low.

True or False?

A

True - with one exception being Japan 2011 tsunami

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28
Q

What is the name of the updated version of the Richter scale, now used to calculate Earthquake magnitude?

A

Moment Magnitude Scale (MMS)

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29
Q

What is the name of the type of scale which MMS uses to display earthquake strength?

(e.g where a magnitude 6 earthquake has 10x more ground shaking than a magnitude 5)

A

Logarithmic scale

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30
Q

What does the older Mercalli scale measure in regard to Earthquakes?

A

What people actually feel during an earthquake

e.g the intensity of the shaking not just the total energy released

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31
Q

Why can the Mercalli scale not be easily used to compare the severity of an earthquake based on what people ‘feel’?

A

The shaking people ‘feel’ depends on building quality, ground conditions and other factors

e.g a Mercalli scale VII in Christchurch, NZ may be a scale X in Sichuan, CH - despite being the same magnitude (MMS)

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32
Q

Why might some earthquakes with lower magnitudes still cause significant death tolls?

A

They can trigger secondary impacts (e.g tsunamis or landslides)

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33
Q

How does the location of an earthquake affect its death toll?

A

Earthquakes in urban areas have greater impacts than in rural areas due to higher population density

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34
Q

Why might isolated areas experience higher death tolls after an earthquake?

A

Rescue and relief efforts, including urgent medical aid, take longer to reach these areas

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35
Q

Why might a very high magnitude earthquake cause no death in some cases?

A

If the earthquakes epicentre occurs in an unoccupied area

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36
Q

What does the Volcanic Explosivity Index (VEI) measure?

A

The magnitude of a volcanic eruption

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37
Q

What 3 factors combine to create a score of 0-8 on the Volcanic Explosivity Index?

A
  1. Eruption Height
  2. Volume of material released (ash, tephra etc.)
  3. Duration of eruption
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38
Q

What range on the VEI scale correlates to an ‘Effusive’ eruption?

A

VEI 0-3

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39
Q

At what 2 boundaries are low magnitude, ‘effusive’ eruptions most common?

A
  1. Constructive plate boundaries
  2. Mid-plate hotspots
40
Q

What range on the VEI scale correlates to an ‘Explosive’ eruption?

A

VEI 4-7

41
Q

At what boundaries are high magnitude, ‘explosive’ eruptions most common?

A

Destructive plate boundaries

42
Q

What range on the VEI scale correlates to a ‘Colossal’ supervolcano eruption?

A

VEI 8+

43
Q

What is a famous example of a VEI 8+ supervolcano that would bring global cooling if it erupted, with impacts lasting up to 5 years?

A

Yellowstone

  • No modern human has ever experienced the impacts of a VEI 8+ eruption
44
Q

Which model - with its continuous line format - can be used to compare the nature and associated risks of tectonic hazards?

A

Tectonic Hazard profile

45
Q

Why are tectonic hazard profiles useful in comparing tectonic events?

A

It visualises the differences between each event (e.g duration, speed of onset, magnitude) comparing multiple aspects of a hazard

  • This takes into account more relevant factors than purely comparing based on magnitude
46
Q

With regard to hazard profiles - why do high magnitude, low-frequency events present a high risk?

A

They are the least ‘expected’ and unlikely to have occurred in living memory

47
Q

With regard to hazard profiles - what makes rapid onset events with low spatial predictability particularly risky?

A

They can occur in numerous places without warning, making them harder to prepare for

48
Q

With regard to hazard profiles - how does regional areal extent, instead of local, contribute to a hazard’s risk level?

A

It affects a large number of people across a wide range of locations

49
Q

Why are major earthquakes at subduction zones and collision zones considered the most dangerous tectonic hazards?

A

Hazard profiles highlight their extreme magnitude (8-9 MMS), unpredictability, and their vast spatial extent (10,000+km) along plate margins

50
Q

How many people died in Chile 2007 (HDI 0.83) compared to Pakistan 2013 (HDI 0.54) in magnitude 7.7 earthquakes?

A

Chile = 2 deaths
Pakistan = 825 deaths

51
Q

How does population growth increase risk during tectonic hazards?

A

Leads to more people in vulnerable areas, and a strain on resources

52
Q

How does urbanisation and sprawl increase risk?

A

Creates dense settlements, often informal housing with no building regulations

53
Q

How does environmental degradation increase risk?

A

Removes natural defences to hazards (e.g mangrove deforestation in Indian Ocean 2004)

54
Q

How does loss of community memory about hazards increase risk?

A

People are less aware of the hazard and therefore are less prepared and slower to respond

55
Q

How does a very young or elderly population increase risk?

A

They are less able to evacuate easily and independently. This can also put caregivers at increased risk.

56
Q

How does outdated infrastructure increase risk?

A

Less resilient to hazards, increasing the likelihood of collapse

57
Q

How does reliance on power, water and communications increase risk?

A

Can disrupt essential services, limiting rescue and recovery efforts

(e.g power and water outages for weeks affected 80% of Christchurch in 2011)

58
Q

How do warning and emergency-response systems mitigate risk?

A

Provide alerts and pre-planned responses, reducing casualties and damage

59
Q

How does economic wealth mitigate risk?

A
  1. Higher quality resilient infrastructure
  2. Quicker recovery
  3. Better response systems
60
Q

How do government disaster-assistance programmes mitigate risk?

A

Provide financial aid, relief services and resources immediately

61
Q

How does insurance mitigate risk?

A

Helps individuals and businesses recover financially

62
Q

How do community initiatives mitigate risk?

A

Promote development of response plans and risk awareness

63
Q

How does scientific understanding mitigfate risk?

A

Improves hazard prediction and early warning systems for evacuation

64
Q

How does hazard engineering mitigate risk?

A

Structures are designed to withstand natural hazards, reducing damage and casualties

65
Q

Natural disasters affect everywhere equally. Areas of low development will feel the same impacts as areas of high development.

True or False?

A

False - areas of low development are initially much more vulnerable

66
Q

Why is vulnerability high in areas with very low development (below 0.55 HDI)?

A

Even in normal times, people lack basic needs such as sufficient water and food

67
Q

How does informal housing contribute to high vulnerability in low-development areas?

A

Housing is built with no regard for hazard resilience, increasing risk of collapse during a disaster

68
Q

How does limited access to healthcare increase vulnerability in low-development areas?

A

Leads to higher rates of disease and illness, making populations less able to survive during natural disaster

69
Q

Why does lower education increase vulnerability in low-development areas?

A

Leads to lower hazard perception and risk awareness, meaning people are less prepared

70
Q

What % of families lived below the poverty line during the Nepal 2015 earthquake?

A

40%

71
Q

What % of families depended on subsistence farming during the Nepal 2015 earthquake, and why was this problematic?

A

Over 90% - many starved to death as crops were destroyed during the earthquake

72
Q

What % of the rural population of Nepal were malnourished in 2015 earthquake, and why was this problematic?

A

Many had stunted growth and were physically too weak to survive the impacts of the earthquake

73
Q

What % of rural Nepal was literate during the 2015 earthquake, and why was this problematic?

A

20-40% were literate - this reduced their ability to understand disaster warnings

74
Q

How does the effectiveness of governments impact resilience during a natural disaster?

A

Government and policies influence a places coping capacity, and determines how well a community can prepare and respond to disasters

75
Q

How is a well-governed country - one which meets basic needs (food, water, healthcare etc.) - more resilient to natural disasters?

A

By meeting food, water and health needs, a population is physically more able to endure/survive a natural disaster

76
Q

How does effective land-use planning reduce disaster risk?

A

Prevents habitation in high-risk areas

(e.g on unstable slopes, liquefaction areas)

77
Q

How does a government with good environmental management reduce vulnerability to secondary hazards?

A

By preventing degradation (e.g deforestation) secondary hazards such as landslides are less severe

78
Q

How do government-supported education programs reduce disaster risk?

A

Teaches people how to prepare, evacuate and respond during disasters

79
Q

How does corrupt governance affect vulnerability to a natural disaster?

A

Corruption - such as mismanagement of funds or bribery - may mean less focus is on effective disaster management and unsafe building practice

80
Q

How does government openness and accountability increase resilience to natural disasters?

A

More effectively able to convey disaster warnings (e.g through the media) to their population and are considered more trustworthy

81
Q

How do government-supported disaster management agencies (non-profits) increase resilience?

A

Agencies (such as FEMA) require funding from the government (as they are non-profits) to ensure they can co-ordinate effective disaster responses

82
Q

How can good governance reduce the vulnerability of high population densities in tectonic hazard areas?

A

Evacuation plans and zoning laws

(e.g Naples surrounding Mt. Vesuvius)

83
Q

Why are urban areas with more government assets likely to be more resilient during disasters?

A

They are likely to have well-stocked hospitals and good transport links in the event of disaster

84
Q

When were the earthquakes in Christchurch, NZ? (developed)

A

Began late 2010, with the most destructive shock in Feb 2011

85
Q

When was the 7.0 magnitude earthquake in Port-au-Prince, Haiti? (developing)

A

2010

86
Q

What were the focal depths for Christchurch and Haiti respectively?

A

Christchurch = very shallow (5km)

Haiti = relatively shallow (13km)

87
Q

For how long had the Enriquillo-Plaintain Garden Fault been locked, prior to Haiti 2010?

A

250 years - creating substantial pressure

88
Q

How many people died in Christchurch 2011 compared to Haiti 2010

A

Christchurch = 185 killed
Haiti = 300,000 killed

(300,000 more also injured in Haiti)

89
Q

How many homes were demolished in Christchurch 2011 compared to Haiti 2010?

A

Christchurch = 1000
Haiti = 105,000

90
Q

For how long did schools close in Christchurch 2011?

A

2 weeks

91
Q

What % of people temporarily left Christchurch in the immediate aftermath of the 2011 earthquake?

A

Around 1/5

  • only 5-8% of the previous total population of Christchurch left permanently after the event
92
Q

50% of what type of public sector buildings were entirely destroyed by the Haiti 2011 earthquake?

A

50% of all hospitals/healthcare buildings

93
Q

What deadly waterborne disease broke out in Haiti by November 2010?

A

Cholera

94
Q

What were the respective % of GDP which damages related to earthquakes accounted for in Christchurch 2011 and Haiti 2010?

A

Christchurch = 20% of GDP ($28bn)

Haiti = 120% of GDP (around $8bn)

95
Q

Why was the economic shock in Christchurch 2011 less significant than in Haiti 2010, despite higher losses? ($28bn vs $8bn)

A

New Zealand had a stronger economy to deal with the shock than Haiti

  • whilst Christchurch’s losses were greater in absolute terms ($28bn), the economic shock was less severe than in Haiti ($8bn)
96
Q

Long term, what % of Haitians lost their job following the 2010 earthquake?

A

20%

97
Q
A

1 Tectonic Processes and Hazards (3 decks)

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