Tectonic Processes and Hazards - 2 Tectonic hazards and disasters

Question 1

What is a hazard?

Answer 1

‘A perceived natural/geophysical event that has the potential to threaten both life and property’ (Whittow). Yet a geophysical hazard event would not be such without, for example, people at or near its location. That is to say, earthquakes would not be hazards if people did not live in buildings that collapse as a result of ground shaking. Many hazards occur at the interface between natural and human systems.

Question 2

What is a disaster?

Answer 2

The realisation of a hazard, when it ‘causes a significant impact on a vulnerable population’ (Degg). The Centre for Research on the Epidemiology of Disasters (CRED) states that a hazard becomes a disaster when:

• 10 or more people are killed, and/or
• 100 or more people are affected.

Question 3

How does the UN’s International Strategy for Disaster Reduction (ISDR) define disaster?

Answer 3

‘A serious disruption to the functioning of a community or a society involving widespread human, material, economic or environmental losses and impacts, which exceeds the ability of the affected community or society to cope using its own resources.’

Question 4

What are alternative interpretations of disaster?

Answer 4

Alternative interpretations of disaster are provided by some large insurers, which define it as economic losses over $1.5 million.

Question 5

What does Degg’s Model show?

Answer 5

Degg’s Model shows the interaction between hazards, disaster and human vulnerability. Importantly, disaster may only occur when a vulnerable population is exposed to a hazard.

Question 6

Why is the relationship between risk, hazards and people complex?

Answer 6

1 Unpredictability - many hazards are not predictable; people may be caught out by either the timing or magnitude of an event.
2 Lack of alternatives - people may stay in a hazardous area due to a lack of options. This may be for economic reasons (work), because of a lack of space to move, or a lack of skills or knowledge.
3 Dynamic hazards - the threat from hazards is not a constant one, and it may increase or decrease over time. Human influence may also change the location or increase the frequency or magnitude of hazardous events.
4 Cost-benefit - the benefits of a hazardous location may well outweigh the risks involved in staying there. Perception of risk may also play a role here.
5 ‘Russian roulette reaction’ - the acceptance of the risks as something that will happen whatever you do, that is, one of fatalism.

Question 7

What is risk?

Answer 7

The exposure of people to a hazardous event. More specifically, it is the probability of a hazard occurring that leads to the loss of lives and/or livelihood.

Question 8

What is the hazard risk equation?

Answer 8

Risk = hazard x exposture x vulnerability/manageability

Question 9

How can risks be understood through perception?

Answer 9

For example, when there is increasing stress from natural hazards, there may come a point when the population or community has to ‘adjust’.

Question 10

Why will the balance between absorption and adjustment vary?

Answer 10

The balance between absorption and adjustment will vary according to the type of hazard, as well as the attitudes of decision makers.

Question 11

What is resilience?

Answer 11

In the context of hazards and disasters, resilience can be thought of as the ability of a system, community or society exposed to hazards to resist, absorb and recover from the effects of a hazard.

Question 12

According to the United Nations Office for Disaster Risk Reduction (UNISDR), what is the resilience of a community determined by?

Answer 12

According to the United Nations Office for Disaster Risk Reduction (UNISDR), the resilience of a community in respect to potential hazard events is determined by the degree to which the community has the necessary resources and is capable of organising itself both prior to and during times of need.

Question 13

What two important trends are highlighted by the Disaster Risk and Age Index?

Answer 13

The Disaster Risk and Age Index highlights two important trends:
1 ageing populations
2 the acceleration of risk in a world that is increasingly exposed to a range of hazard types.

Question 14

According to the Disaster Risk and Age Index, what percentage of the world’s population aged over 60 live in less-developed regions?

Answer 14

Around 66 per cent of the world’s population aged over 60 live in less-developed regions. By 2050, this is expected to rise to 79 per cent.

Question 15

According to the Disaster Risk and Age Index, what percentage of the world’s population is expected to live in less-developed regions by 2050?

Answer 15

79 per cent

Question 16

How can Myanmar and Japan be compared in terms of their hazard and exposure score?

Answer 16

Myanmar
Myanmar has a significantly high natural hazard component due to the potential for tsunami and earthquakes (as well as floods and storms).

Japan
Japan is subject to a range of natural hazards and is highly exposed.

Question 17

How can Myanmar and Japan be compared in terms of their vulnerability?

Answer 17

Myanmar
Moderate risk though a relatively low score - there have been few natural shocks in recent years.

Japan
Vulnerability is high compared to other wealthy nations due to the ageing population, but it is still low risk.

Question 18

How can Myanmar and Japan be compared in terms of their coping capacity?

Answer 18

Myanmar
Poor coping capacity; low level of internet/mobile phone access for older people; education is poor.

Japan
Coping capacity is good; the elderly tend to be educated, have high internet connectivity, effective government and low gender inequality.

Question 19

How can Myanmar and Japan be compared in terms of their overall risk to disaster?

Answer 19

Myanmar
Myanmar is ranked 7th out of 190 nations, which means that the disaster risk to elderly citizens is very high.

Japan
Although Japan is highly exposed to natural hazards, it is ranked 133rd out of 190 nations thanks to its strong coping capacity and lower levels of vulnerability.

Question 20

How many people were killed in Japan by the tsunami of 2011?

Answer 20

15,000

Question 21

How many people were either injured or missing in the Japan tsunami of 2011?

Answer 21

9500

Question 22

What percentage of people who died in the Japanese tsunami were aged 65 and over?

Answer 22

56 per cent of those who died in the tsunami were aged 65 and over, even though this age group compromised just 23 per cent of the population in the area affected.

Question 23

g

Answer 23

g

Question 24

According to the Pressure and Release Model (PAR) Model (also known as the Disaster Crunch Model), what is a disaster the intersection of?

Answer 24

The basis for the Pressure and Release (PAR) Model (also known as the Disaster Crunch Model) is that a disaster is the intersection of two processes:
1 processes generating vulnerability on one side, and
2 the natural hazard event on the other.

Question 25

f

Answer 25

R

Question 26

What are some examples of the root causes in the Pressure and Release Model (PAR) Model?

Answer 26

Root causes

Limited access to:

• Power
• Structures
• Resources

Ideologies

• Political systems
• Economic systems

Question 27

What does root causes, such as limited access to power and resources, create?

Answer 27

Root causes, such as limited access to power and resources, create vulnerability through different pressures such as inadequacies in training, local institutional systems, or capacity and standards in government.

Question 28

What are some examples of the dynamic pressures in the Pressure and Release Model (PAR) Model?

Answer 28

Dynamic pressures

Lack of:

• Appropriate skills
• Training
• Local investment
• Press freedom
• Ethical standards in public life

Macro forces:

• Rapid population change
• Rapid urbanisation
• Deforestation
• Arms expenditure
• Debt repayment schedules

Question 29

What are some examples of unsafe conditions in the Pressure and Release Model (PAR) Model?

Answer 29

Unsafe conditions

• Fragile physical environment
• Fragile local economy
• Vulnerable society
• Public actions

Question 30

What do dynamic pressures produce in the physical and social environments of the groups and people most susceptible to vulnerability and risk?

Answer 30

Unsafe conditions

Question 31

What is disaster-risk the result of?

Answer 31

Risk = hazard + vulnerability

Question 32

Why do the social and economic impacts of tectonic hazards vary?

Answer 32

The social and economic impacts of tectonic hazards vary considerably in terms of time and, more importantly, geographical region. They may vary from minor nuisances to major disasters involving a considerable impact on people in terms of loss of livelihood or even death.

Question 33

Why are the impacts of earthquakes (and linked secondary effects) generally much greater than those presented by volcanoes?

Answer 33

The concentration of volcanoes in relatively narrow belts means not only that a relatively small proportion of the land area of the world is close to a volcano but that a relatively small proportion of the human population has direct exposure to volcanic activity. Somewhat less than one per cent of the world’s population is likely to experience risk from volcanic activity, whereas the figure for earthquakes (directly) is estimated to be five per cent. That figure rises considerably when secondary impacts are considered (landslides and tsunami, for instance).

Question 34

What percentage of the world’s population is likely to experience risk from volcanic activity, compared to the figure estimated for earthquakes?

Answer 34

Somewhat less than one per cent of the world’s population is likely to experience risk from volcanic activity, whereas the figure for earthquakes (directly) is estimated to be five per cent.

Question 35

What are the economic impacts of volcanoes roughly proportional to?

Answer 35

The economic impacts are roughly proportional to the land area exposed to the relevant hazard.

Question 36

What do the economic impacts of tectonic hazards need to be considered more carefully against?

Answer 36

Economic impacts need to be considered more carefully set against the context, for example:
1 level of development (region or country)
2 insured impacts versus non-insured losses
3 total numbers of people affected and the speed of economic recovery following the event (a measure of resilience)
4 degree of urbanisation and, linked to this, land values, and the country or region’s degree of interdependence
5 absolute versus relative impacts on a country’s gross domestic product (GDP); higher relative impacts are more devastating.

Question 37

What is development?

Answer 37

Development is linked to an improving society, enabling people to achieve their aspirations. It includes the provision of social services, acquisition of economic assets, improved productivity and reducing vulnerability to natural disasters. Low levels of development are closely associated with high levels of risk and vulnerability to natural disasters.

Question 38

What are the four types of scales used for different types of tectonic hazard?

Answer 38

Richter scale
Mercalli Scale (modified)
Moment Magnitude Scale (MMS)
Volcanic Explosivity Index (VEI)

Question 39

What does the Richter Scale measure?

Answer 39

Hazard
Earthquake

Scale
0-9

Overview
A measurement of the height (amplitude) of the waves produced by an earthquake. The Ritcher Scale is an absolute scale; wherever an earthquake is recorded, it will measure the same on the Richter Scale.

Question 40

Why is the Ritcher Scale an absolute scale?

Answer 40

The Ritcher Scale is an absolute scale; wherever an earthquake is recorded, it will measure the same on the Ritcher Scale.

Question 41

What does the Mercalli Scale (modified) measure?

Answer 41

Hazard
Earthquake

Scale
I-XII

Overview
Measures the experienced impacts of an earthquake. It is a relative scale, because people experience different amounts of shaking in different places. It is based on a series of key responses, such as people awakening, the movement of furniture and damage to structures.

Question 42

Why is the Mercalli Scale (modified) a relative scale?

Answer 42

It is a relative scale, because people experience different amounts of shaking in different places.

Question 43

What does the Moment Magnitude Scale (MMS) measure?

Answer 43

Hazard
Earthquake

Scale
0-9

Overview
A modern measure used by seismologists to describe earthquakes in terms of energy released. The magnitude is based on the ‘seismic movement’ of the earthquake, which is calculated from: the amount of slip on the fault, the area affected and an Earth-rigidity factor. The USGS uses MMS to estimate magnitudes for all large earthquakes.

Question 44

How is the ‘seismic movement’ of the earthquake calculated by the Moment Magnitude Scale (MMS)?

Answer 44

The magnitude is based on the ‘seismic movement’ of the earthquake, which is calculated from: the amount of slip on the fault, the area affected and an Earth-rigidity factor.

Question 45

What does the USGS use the MMS for?

Answer 45

The USGS uses MMS to estimate magnitudes for all large earthquakes.

Question 46

What does the Volcanic Explosivity Index (VEI) measure?

Answer 46

Hazard
Volcanic eruption

Scale
0-8

Overview
A relative measure of the explosiveness of a volcanic eruption, which is calculated from the volume of products (ejecta), the height of the eruption cloud and qualitative observations. Like the Richter Scale and MMS, the VEI is logarithmic: an increase of one index indicates an eruption that is ten times as powerful.

Question 47

How is the explosiveness of a volcanic eruption calculated?

Answer 47

The volume of products (ejecta), the height of the eruption cloud and qualitative observations.

Question 48

f

Answer 48

f

Question 49

f

Answer 49

f

Question 50

f

Answer 50

f

Question 51

f

Answer 51

f

Question 52

What are hazards managers also considering as a tool to help understand risk?

Answer 52

Increasingly hazards managers are also considering magnitude-frequency relationships as a tool to help understand risk. These probability-based estimates help engineers plan and design key infrastructure in hazard-prone areas. Such modelling is based on the general assumption that magnitude is often inversely proportional to the frequency of a particular event, that is, large earthquakes are much rarer than small ones.

Question 53

What are hazard frequency relationships based on?

Answer 53

Such modelling is based on the general assumption that magnitude is often inversely proportional to the frequency of a particular event, that is, large earthquakes are much rarer than small ones.

Question 54

What is a tectonic hazard profile?

Answer 54

A technique used to try to understand the physical characteristics of different types of hazards, for example, earthquakes, tsunamis and volcanoes. Hazard profiles can also be used to analyse and assess the same hazards which take place in contrasting locations or at different times. Hazard profiles are developed for each natural hazard and are based on criteria such as frequency, duration and speed of onset.

Question 55

What does a hazard profile compare and help decision makers to identify?

Answer 55

A hazard profile compares the physical processes that all hazards share and helps decision makers to identify and rank the hazards that should be given the most attention and resources.

Question 56

What is one of the difficulties with hazard profiling?

Answer 56

One of the difficulties with hazard profiling, however, is the degree of reliability when comparing different event types. It is relatively easy to compare, say, an earthquake in Nepal to an earthquake in California because they are measured using similar scales or metrics and cause similar types of damage. However, it is much more difficult to compare across hazards, for example an earthquake to a tsunami or a volcanic eruption, as they all have different impacts on society and have varying spatial and temporal distributions. To accurately rank multiple hazards on one scale certain elements of the hazard become inaccurately displayed or must be omitted from the profile itself.

Question 57

What has the traditional strategy for hazard planning been?

Answer 57

The traditional strategy for hazard planning has been on an individual hazard-by-hazard basis.

Question 58

Why can the traditional strategy for hazard planning on an individual hazard-by-hazard basis be problematic?

Answer 58

This type of hazard planning can be problematic, however, due to conflicts between cost and government willingness to pay, and the resources available.

Question 59

How can disaster vulnerability be compared between developed and developing/emerging countries?

Answer 59

Developed
Population millions
Low birth rate
Wealthy people
Resource surplus
Large cities
High technology
Safe environments
Secure livelihoods
Global economy
Aid source
Independence
Many choices

Developing/Emerging
Population billions
High birth rate
Poor people
Resource deficit
Megacities
Low technology
Unsafe environments
Fragile livelihoods
Local economy
Aid sink
Dependence
Few choices

Question 60

What does the Disaster Risk Index (DRI) seek to combine?

Answer 60

This index seeks to combine physical exposure to hazards with vulnerability.

Question 61

According to the Disaster Risk Index (DRI), which countries are the top in terms of numbers of people killed per year (absolute)?

Answer 61

The top countries at risk in terms of numbers of people killed per year (absolute) are the most populated countries (China, India, Indonesia, Bangladesh).

Question 62

According to the Disaster Risk Index (DRI), which countries come first in terms of numbers killed per million inhabitants per year (relative)?

Answer 62

Small island states (Vanuatu, Dominica, Mauritius, Antigua and Barbuda, St Kitts and Nevis, Solomon Islands, Grenada, and so on).

Question 63

What are the most important causes in the ‘root cause’ phase of the PAR Model?

Answer 63

In the ‘root cause’ phase of the PAR Model, the most important causes are those which have an economic, demographic or a political foundation.

Question 64

How can risk vulnerability be explained for people in developing and recently emerging countries who tend to have less power over their socio-political and physical environments?

Answer 64

• People and communities in developing and recently emerging countries only have access to livelihoods and resources that are insecure and difficult.
• They are likely to have a low priority for government interventions intended to deal with hazard mitigation.
• People who are economically and politically ‘on the edge’ are more likely to stop trusting their own methods for self-protection and to lose confidence in their own local knowledge. This means they rely more on government help, which may actually not work very well for them or their families.

Question 65

What are the consequences for people who are economically and politically ‘on the edge’?

Answer 65

People who are economically and politically ‘on the edge’ are more likely to stop trusting their own methods for self-protection and to lose confidence in their own local knowledge. This means they rely more on government help, which may actually not work very well for them or their families.

Question 66

What are people’s basic health and nutritional status an important measure of?

Answer 66

People’s basic health and nutritional status correlate strongly with their ability to survive disruptions to their livelihood and normal well-being. It is an important measure of their resilience when dealing with the external shock from hazard events.
There is also a clear relationship between nutrition and disease, which is often evident after a hazard impact (especially when people are forced to find shelter and come into close contact with one another). People who are undernourished and sick are at greater risk of disease as they have weaker immune systems.

Question 67

What are the several elements of development that relate to vulnerability and disaster risk?

Answer 67

1 An economic component dealing with the creation of wealth and the improvement of quality of life which is equally distributed.
2 A social dimension in terms of health, education, housing and employment opportunities.
3 An environmental strand which has a duty of care for resource usage and distribution, now and in the future.
4 A political component including values such as human rights, political freedom and democracy.

Question 68

In the aftermath of the devastating Haiti earthquake in 2010, how many people were estimated to have died from cholera, and how many people were thought to be affected?

Answer 68

In the aftermath of the devastating Haiti earthquake in 2010, for example, an estimated 9000 people died from cholera, and around 700,000 were thought to be affected.

Question 69

Why is Haiti an example of a country where level of development may contribute towards disasters by increasing vulnerability as well as creating new hazard?

Answer 69

The source of the 2010 outbreak is disputed but it centres around the Artibonite River, from which most of the affected people had drunk water. There was suspicion among Haitians that a UN military base, located on a tributary of the river and home to peacekeepers from Nepal (who had come to help with the recovery) was actually the source of the disease). They thought that the base could have caused the epidemic, and this was confirmed in 2011 by the UN who stated that there was ‘substantial evidence that the Nepalese troops had brought the disease to Haiti’.

Question 70

What caused the epidemic in the aftermath of the devastating Haiti earthquake in 2010?

Answer 70

f