D.2 - Geophysical Hazard Risks

Question 1

Define hazard

Answer 1

-Any threat which can cause loss of life, injury, property damage, environmental degradation
etc.
-Has the potential to affect people

Question 2

Define hazard event

Answer 2

• The occurrence of a hazard which has negative impacts
• Accompanied by the resulting demographic/economic/environmental conditions

Question 3

Define hazard perception

Answer 3

• The degree to which a hazard is considered a threat by different people

Question 4

Define resilience

Answer 4

• The ability to protect lives/infrastructure from destruction and recover after a hazard event

Question 5

Define adaptation

Answer 5

• Altering human actions to account for increasing hazard risks

Question 6

Define geophysical hazard

Answer 6

• A hazard associated with the earth’s processes

Question 7

Define disaster

Answer 7

• Major hazard events that cause widespread disruption to a community/region
• Lead to significant demographic/economic/environmental losses
• Affected community is incapable of dealing with it adequately without outside help

Question 8

Where are volcanos found

Answer 8

Concentrated along convergent plate boundaries where subduction occurs
Can also be found at divergent plate boundaries or above a hot spot

Question 9

Where are earthquakes found

Answer 9

Found at all three plate boundaries
The most hazardous ones occur at convergent boundaries

Question 10

Where are tsunamis found

Answer 10

Begin near the epicentre of EQs, then radiate outwards far along ocean waters

Question 11

Where is mass movement found

Answer 11

Result of gravity
Most likely to occur on steep hills, especially with heavy rainfall, frequent freeze-thaw, snowfall, and limestone rocks

Question 12

Define risk management

Answer 12

• Identifying, assessing, and prioritising risks
• Allocating resources in effective coordinated manner to reduce potential hazards
• To be effectively implemented, requires the measurement of the magnitude, frequency, and likely recurrence of hazards

Question 13

What are 2 ways of measuring earthquakes

Answer 13

• Richter scale
• modified mercalli intensity scale

Question 14

What is the Richter scale

Answer 14

Most common method
Measures amount of seismic energy released in an EQ
Uses a logarithmic scale from 0-10+
A difference of one represents an approximate thirtyfold difference in magnitude
EQs measuring 5+ can cause destruction
Over 7 will cause major damage if near settled areas
Allows easy comparison of EQ magnitudes, regardless of the location

Question 15

What is the modified mercalli intensity scale

Answer 15

Designates Roman numerals to represent EQ intensity, ranging from imperceptible shaking to catastrophic destruction
No mathematical basis
Uses arbitrary rankings based on observed effects
E.g. if furniture moves, if buildings collapse, if people are frightened
Can be useful as its descriptions can be related to observations
However, useless in places without trees, houses, railways etc.
Can also be variable, depending on personal interpretations

Question 16

How are the volcanos formed

Answer 16

The volcanoes in the Pacific Rim or Ring of Fire are caused by the subduction beneath either the oceanic or continental crust. Subduction in the oceans provides chains of volcanic islands known as island arcs, such as the Aleutian Islands formed by the Pacific Plate subducting beneath the North American Plate. Where the subduction of an oceanic crust occurs beneath the continental crust, voung fold mountains are formed. The Andes, for example, have been formed where the Nazca Plate subducts beneath the South American Plate.

Question 17

Where are most volcanos found

Answer 17

The pacific ring of fire

Question 18

Where a landslides most likely to occur

Answer 18

Landslides are naturally occurring phenomena in every environment on Earth, including the tropics, the temperate regions, the high latitudes and also the ocean. However, fatal landslides tend to be more common in areas that have:
active tectonic processes that lead to high rates of uplift and occasional seismic events
• high levels of precipitation, including high annual totals and high short-term intensities
• a high population density.

Question 19

define risk

Answer 19

The probability of a hazard event causing harmful consequences

Question 20

Define disaster risk

Answer 20

Consequence of interaction between a hazard and the characteristics that make places vulnerable

Question 21

Define vulnerability

Answer 21

• The characteristics of a community that make it susceptible to damage from hazard events
• Rich countries are more vulnerable to economic costs
• Poorer countries are more vulnerable to social costs

Question 22

Define capacity

Answer 22

• Ability for a community to absorb and ultimately recover from a natural disaster
• E.g. hazard mapping, early warning systems, effective communication, availability of emergency response

Question 23

What are 5 ways of measuring risk

Answer 23

• disaster recovery index
• disaster deficit index
• local disaster index
• prevalent vulnerability index
• risk management index

Question 24

What is disaster recovery index

Answer 24

Estimates risk of loss of life
Ignores possible damage to livelihoods and the economy
Considers the hazard, population size, and the vulnerability of the population
Good at clearly highlighting hazard risk and avoiding problems when comparing countries with fluctuating currency exchange rates
However, estimating number of deaths is difficult, and doesn’t measure gov’t capacity to improve state of development to reduce risk

Question 25

What is disaster deficit index

Answer 25

Models consequences of hazard events in macroeconomic and financial terms
Represents maximum probable loss, and capacity of country to deal with it Informs if governments will be able to raise sufficient funds to cope with losses

Question 26

What is local disaster index

Answer 26

Measures social environmental risks at a local scale
Particularly looks at those with a greatest impact on poorer people

Question 27

What is prevalent vulnerability index

Answer 27

Composite measurement based on indicators for exposure, socio-economic fragility, and resilience
However, requires more data which may be difficult to gather in poorer countries

Question 28

What is risk management index

Answer 28

Composite measure based on indicators of risk identification/reduction, hazard reduction, and effectiveness of governance
Estimates risk management in terms of institutional organisation, capacity, and development to reduce losses

Question 29

What is troubling about analysing risks

Answer 29

• Insurance companies try to analyse and predict hazards in a very detailed manner
• However, errors can occur
• Challenging due to the many variables and different time scales to consider (e.g. both direct and indirect effects)
• Can often be misjudged as planners underestimate the severity or frequency of hazards, for a variety of reasons

Question 30

What three reasons make it troublesome to analyse risks

Answer 30

• economically poor countries
• lack of data
• psychological denial

Question 31

Why are hazards in economically poor countries difficult to analyse

Answer 31

Gov’ts may deliberately minimise severity of hazards to spare certain companies the expense of dealing with the remedies required

Question 32

Why does the lack of data make hazards difficult to analyse

Answer 32

People may lack the necessary long-term data and information to accuratelv assess risk

Question 33

Why does psychological denial make it difficult to analyse hazard s

Answer 33

People may understand the risk but psychologically suppress it so the benefits of living in the area are not challenged

Question 34

What are 2 social reasons people live in hazardous environments

Answer 34

• must live where they are born
  Due to extended family ties, being in debt to a landlord, lack of finances to move
• they do not realise there is a hazard where they live
  e.g. EQs can strike in places with no prior history of EQs

Question 35

What are 4 economuc reasons people live in hazardous environments

Answer 35

• fertile soils near active volcanos
  Volcanoes erupt and distribute ash which aids the fertilitv of soils
  Good for cultivation
• employment
  Farmers may lack skills required to gain employment if they moved to urban areas
• living costs
  Hazardous areas cost less to live in
• tourism
  Wild, raw, barren volcanic landscapes can attract tourists

Question 36

What are 7 social factors affecting geogphysical hazard risks

Answer 36

• less education
• gender
• remoteness and isolation
• building type
• children
• higher population density
• large amounts of recent arrival

Question 37

How does less education create more hazard risk

Answer 37

Less likely to recognise dangers of living in hazard areas
Less able to take preventative action e.g. in wealthier and educated countries like
Japan and USA, students routinely practice EQ drills to prepare for hazards

Question 38

How does gender create higher risk of hazard

Answer 38

Tend to have less access to resources, and be the main caregivers
Less able to respond to disasters with the resources needed to

Question 39

How’d ones remoteness and Isolation create geophazard risks

Answer 39

Rescue services take longer to reach the site Communications may be less reliable, with less developed telephone/internet links
Often have less well-equipped hospitals and emergency centres, requiring injured to be transported long distances for treatment

Question 40

How does building type create geophysical hazard risk

Answer 40

Lower buildings are more susceptible
Taller buildings are typically more flexible and thus safer

Question 41

How dies children make a area more affect by geophysical hazards

Answer 41

Vulnerable to long-term psychological problems as they can’t fully understand what is happening
Can be vulnerable to disease and death if infections break out

Question 42

how does a higher population density make you more vulnerable to geophysical hazards

Answer 42

More difficult evacuations
More difficult to get rescue crews into these areas

Question 43

How does large amounts of arrival make a area more affect by geophysical factors

Answer 43

Less likely to know their way around, making evacuation less efficient
Less likely to know about potential geophysical hazards

Question 44

What are 3 economic factors affecting geophysical hazard risk

Answer 44

• cheap housing
• poorer countries
• wealthier countries

Question 45

How does cheap housing affect geophysical hazard risk

Answer 45

Many poor people live in shanty settlements which lack basic facilities like clean water, drainage, and telecommunications
They are also often built in high-risk locations, near steep valley sides, flood-prone rivers, and on fault lines of tectonic plates

Question 46

How do poorer countries create geophysical hazard risk

Answer 46

Technology is often inadequate
Harder to pay for early warning systems to warn of impending risks
Building standards are often low to save funds or due to corruption between building developers and gov’t officials
Thus, many structures are damaged and can possibly trap people inside
Tend to have poorer emergency services with less personnel
e.g. relief workers may work with shovels compared to ultrasound search devices, ambulances, and excavation equipment etc.
Worse education, poorer funded gov’t agencies, less money to pay for repairs, less change of back-up communication lines
Less likely to have insurance coverage against disasters, to repairs take longer to be made

Question 47

How does wealthier countries affect geophysical hazard risks

Answer 47

Infrastructure is likely to have greater financial value with higher construction costs and greater levels of services provided
Tend to have assets with higher cash values which cost more to repair
Thus, hazard events will have greater financial costs (although damage typically represents greater proportions of total wealth in poorer countries)

Question 48

What are 2 political factors affecting geophysical hazard risk

Answer 48

• political conflict
• political structure

Question 49

How does political conflict affect geophysical hazard risk

Answer 49

Civil unrest and conflict can impede rescue efforts
e.g. frequent EQs/mass movements in
Afghanistan

Question 50

How does political structure affect geophysical hazard risk

Answer 50

Can be a barrier to mounting effective rescue events

e.g. Chinese government in 1970s routinely practiced secrecy, so EQs were reported days after occurring, delaying initial rescue and recovery efforts

Question 51

What are 4 factors affecting geophysical hazard event impact

Answer 51

• physical location
• time of days
• urban areas
• rural areas
• population density
• rock type and sediment
• economic development

Question 52

How does physical location affect geophysical hazard event impact

Answer 52

Places found on plate boundaries have higher risks of experiencing EQs or eruptions
Locations on steep mountain sides are more likely to experience mass movement events

Question 53

how does time of day affect geophysical hazard event impact

Answer 53

Hazards that strike at busier times of day often cause more deaths and injuries
More people are out in the streets, away from familiar areas
Congested streets make it more difficult for rescue vehicles to move around and help victims

Question 54

how does urban areas affect geophysical hazard event impact

Answer 54

More vulnerable to falling walls and collapsing buildings

Question 55

How does rural areas affect geophysical hazard event impact

Answer 55

More vulnerable to landslides as unstable slopes are less likely to have been stabilised and strengthened
They have fewer rescue services to respond

Question 56

How does pop;latino density affect the impact of a geophysical event

Answer 56

a geophysical event that hits an urban area of high population density, such as in the Tokyo area of Japan, could inflict far more damage than one that hits a rural area of low population and building density. Most of the deaths in the 1985 Mexico City earthquake occurred in the city, despite the focus being over 200 km away.

Question 57

How does building type affect the impacts of geophysical events

Answer 57

high-income countries generally have better-quality buildings that have been built to be earthquake resistant.
The 2010 Port-au-Prince earthquake destroyed more buildings than the 2010-2011 New Zealand earthquakes although they were of comparable magnitude. People in high-income countries are also more likelv to have insurance cover than those in low-income countries, so recovery after the event is easier.

Question 58

How does rock type and sediment affect the impacts of geophysical hazards

Answer 58

loose materials may act like liquid when shaken, a process known as liquefaction. Solid rock is much safer, and buildings built on flat areas of solid rock are more earthquake resistant. Unconsolidated volcanic sediments are at high risk of landslide compared with solid geology, for example the Casita volcano in Nicaragua following Hurricane Mitch.

Question 59

How does economic development affect the impacts of geophysical events

Answer 59

Economic development: high-income countries will generally have a better level of preparedness and more effective emergency response services, better access to technology and better health services. There will be more funds to cover the cost of coping with disasters. The responses to the Christchurch earthquakes in New Zealand were more effective than the responses to the Port-au-Prince earthquake in Haiti.

Question 60

How does construction styles and building codes affect the vulnerability of a area to geophysical hazards

Answer 60

Construction styles and building codes: there was criticism during the Sichuan earthquake that whereas government buildings remained standing many schools were destroyed (suggesting that the schools were poorly built).

Question 61

How does access to technology affect the vulnerability of an area to a geophysical hazard

Answer 61

Access to technology: in Japan, earthquake and tsunami warnings are issued to people via smartphones; people with greater access to communications are better able to keep up to date with warnings and forecasts.

Question 62

What are some demographic factors that affect the vulnerability of an area to geophysical hazards

Answer 62

• Population density: a large number of rapidly growing cities are in hazardous areas; large urban areas such as Port-au-Prince in Haiti are especially vulnerable to natural hazards
• Age: 65 per cent of those who died in the Japanese tsunami in 2011 were aged over 60.
• Migrants: when people move to an area they may be unaware of some of the natural hazards present in that environment.
• Disability: the mortality rate of the disabled in the Japanese tsunami of 2011 was twice that of the normal population.
• Cultural factors: some of the cultural factors that influence public response to warnings are: the extent of trust in government, scientists or other authority figures; the extent and success of social networks; the amount of control or autonomy that a community feels it has; and the perceived hazard level.

Question 63

What is the recurrence interval or return period

Answer 63

The recurrence interval or return period is the expected frequency of occurrence in years for an event of a particular size. In general, small events have a high frequency/short return period whereas large events have a very low frequency/high return period. Thus there are fewer highly destructive earthquakes but many minor ones (Table D.3 and Figure D. 14). These are generalized into high-frequency/low-magnitude events versus low-frequency high-magnitude events. Low-frequency high-magnitude events cause the most destruction and require the greatest management.