Hazards COPY Flashcards
what is a hazard?
it is a potential threat to human life and property. it can either be hydro-meteorological or geophysical
what are hydro-meteorological hazards?
caused by climatic processes
what are geophysical hazards?
caused by land processes
where do geophysical hazards occur?
they occur near plate boundaries. these plates moved different speeds and directions which can cause collisions, earthquakes and volcanic activity.
where do earthquakes mainly take place?
greatest in the Pacific Ocean along the ring of fire. also the entire ocean is ringed by areas known as subduction zones.
where do the most powerful earthquakes generally happen?
at convergent or conservative boundaries
why is reporting disaster impacts (e.g. fatalities) very difficult and controversial?
- depends on whether you look at the direct deaths so those killed straight away or indirectly by looking at how many people died of diseases that spread after the disaster
- the location is important as rural and isolated areas are hard to reach and so it may be hard to collect data from them.
also areas of high pop densities may be hard to collect from - the number of deaths quoted by a government may be subject to bias. in the 2004 tsunami, the Burmese government claimed there were 0 deaths in Burma. this may be to try and show the government is doing a good job.
where are volcanoes predominately located?
along the ring of fire which borders the indo-australian plate to the south west, the Eurasian plate to the north west and the North American plate to the west
- they are usually found at plate boundaries where plates converge or diverge, anomalies include hotspots.
what is the epicentre?
the area above ground that is directly above the hypo centre (shaking tends to be worse here)
what is the hypo centre?
the point at which tension and friction releases seismic waves
where do the most powerful earthquakes occur?
at destructive and conservative boundaries
when will the intensity of seismic waves decrease?
they will decrease further from the epicentre as waves lose energy as they travel. However, this does not mean that impacts felt or damage caused will always decrease further from the epicentre as other factors affect a location’s vulnerability
what are the factors affecting vulnerability for an area?
- Geology
- Geographical location (whether the earthquake occurs nears the sea or intraplate)
- Education of locals
- Durability of buildings
- Mitigation
what are the factors explaining the intensity of an earthquake?
- Seismic intensity = what you feel
- Proximity to the epicentre
- Types of soil / rock and distance from the epicentre
- Magnitude= the size of the earthquake and the energy intensity released
- Depth of focus
- Shallow hypocentre means higher intensity
- Soil substrate, if it is wet, soft or sandy then intensity will rise, liquefaction, soft saturated bay mud is x5 more damaging than bay rock
what is a secondary hazard?
a hazard that is a result of a primary hazard, e.g. landslides, flooding, sinkholes, tsunamis
what is a primary hazard?
caused by the initial process, e.g, the earthquake, ground shaking, crustal fracturing
what is a hazard-management cycle?
a theoretical model of hazard management as a continuous four stage cycle involving: mitigation, preparation, response and recovery
what is rapid onset for a hazard?
a hazard that happens very slowly with plenty of evidence and warning (e.g. drought)
what is the pressure and release model?
a tool used to work out how vulnerable a country is to hazard
what is the United Nations definition for a hazard?
a natural process becomes a hazard when people are affected
what is the United Nations definition for a disaster?
a natural hazard becomes a disaster when it affects a vulnerable population causing over 500 deaths
what is the United Nations definition for a mega-disaster?
when over 2000 people die or 20,0000 people are made homeless of if GDP is reduced by 5% or if dependence of aid lasts for over a year
explain dregs model for a natural disaster
it shows that if you were to combine a hazardous natural event with a vulnerable population susceptible to human and economic loss then you will have a disaster
what is the pressure and release model (PAR model)
- risk can be predicted using PAR model and two hazard risk equations
- PAR model is often known as the disaster crunch model
- it resembles a ‘nutcracker’ as pressure increases from both sides, release of pressure tacking vulnerability to reduce the disaster
It states that vulnerability is a process that starts with root causes. These are political and economic systems that control who has power in a society. Through a series of processes called dynamic pressures, these root causes can lead to unsafe conditions. The process from root causes to unsafe conditions is called the progress of vulnerability.
root dynamic unsafe
causes pressures conditions
DISASTER
hazard
- if the area affected is highly vulnerable from a range of social and environmental factors the disaster is more greatly experienced
- e.g. Haiti had a poor political system which is a root cause of vulnerability, this is because the government is highly corrupt and the humanitarian aid funds did not reach the people in their entirety meaning people and businesses could not cover as quickly meaning the disaster was greater
what are the three types of vulnerability in the PAR model?
root causes (governmental) dynamic pressures (people) unsafe conditions (location)
explain the strand of vulnerability of root causes
1) limited access to:
- power
- structure
- resources
2) ideologies
- political system (corruption)
- economic system
explain the strand of vulnerability of dynamic pressures
1) leads to lack of investment into:
- infrastructure
- education (no warning systems in place)
- Training
- Appropriate skills
- Local investment
- Local market
- Media freedom
- medical care
2) macroforces
- Rapid population increase
- Rapid urbanisation
- Expenditure
- Deforestation
- Decline in soil productivity
explain the strand of vulnerability of unsafe conditions
1) Fragile physical environment
- Dangerous locations (landslide prone)
- Unprotected infrastructure (shanty towns)
2) Fragile local economy
- Livelihoods at risk
- Low income levels
- high inequalities
3) Vulnerable society
- Special groups at risk (elderly)
4) Public actions
- Lack of preparedness
- Epidemic disease
what is the hazard risk equation?
risk reduction = (mitigation of hazard x reduction of vulnerability) / capacity to cope
what is risk/damage threshold?
refers to the classing of different natural hazards based off their magnitude and scale of damage.
When a hazard’s magnitude exceeds the risk/damage threshold the hazard is dangerous to the local population. This can be because the population is vulnerable or the hazard has an extremely high magnitude.
explain the five strands of vulnerability
1) Physical vulnerability
- When people live in hazard-prone areas in building that offers little protection, lack of infrastructure
- Action: move away from hazard-prone areas
2) Economic vulnerability
- dependant on the economic stays of individuals and nations so affected by assets
- poor residents do not have to money to afford recovery and preparation
- Action: Introduce housing insurance, compensation
3) Social vulnerability
- When a household or community is unable to support the disadvantaged people within it, e.g. political isolation may exist for the poor, females, elderly and rural residents
- elderly populations are more vulnerable
- high population density
- Action: Government could provide money
4) Knowledge vulnerability
- When people lack education and training and therefore understanding.
- This leads to the lack of warning or evacuation systems in place
- Action: They must educate people on efficient evacuation routes
5) Environmental vulnerability
- lack of natural resource depletion
- resource degradation making settlements vulnerable, those dependant on resources
- high pop density leading to people being forced into riskier areas
- being on plate boundaries
- Action: They must relieve population pressures by creating new services
what do u believe is the greatest initiative for mitigation?
the greatest initiative for mitigation must come from the government as they have the largest influence/power to implement reforms. They also have the money to maximise their effectiveness and strength. For example, individuals may not have the social influence to make their ideas widespread or the money to successfully enforce them.
why was Haiti vulnerable and had a low capacity to cope?
- Poor structural integrity meaning buildings couldn’t maintain their structure leading to a lack of shelter
- Densely populated so inevitably affected more people
- Lack of government stability reduced spending and preparation as people were less equipped and educated to deal with the risks
- On a plate boundary so suffered from environmental/physical vulnerability
why are hazard profiles?
They are a way of comparing two physical processes and impacts that all hazards share.
They can show intensity, frequency, special extent, duration, speed of onset, death toll, recovery rate and damage ($). It can also compare two areas of events.
evaluate the positives of the use of hazard profiles
- they can compare the vulnerability of areas to different hazards in a range of categories and are an easy visual representation
- they can help areas see what they are most at risk of. because of this, they can plan and prepare more efficiently, helping to mitigate the effects when they come
- it is easy to compare the same type of hazard in two different locations because it breaks the event down into a variety of factors
evaluate the negatives of the use of hazard profiles
- it is difficult to compare two different hazards as they have different impacts, e.g. a volcano may have a larger spatial extent like Hawaii but not be very intense whereas an earthquake may be very intense like Hawaii, but have a low spatial extent
- It is difficult to compare two different hazards because it doesn’t provide specific values for factors leaving it somewhat open to interpretation. They have varying impacts and spatial and temporal distributions
what are the pros and costs on using a hazard profile of 1 area with a range of factors on different types of hazard
pros
- see what an area is most vulnerable to, see how an area can defend against the hazards, e.g. droughts have a slow speed of onset so allows for preparation
cons
- doesn’t compare to other area so hard to see development
- Development is not factored into the different scales so it’s hard to see
what are the pros and cons of comparing two different areas for the same hazard
pros
- see how vulnerable an area is in comparison to another area
- similar impacts so easy to visually compare
cons
- only references one hazard which is less useful in a multiple hazard risk zone
what would the main points be for
‘Assess the reasons why some countries are vulnerable than others to tectonic hazards’ (12)
- Physical location
- Government initiatives / community preparedness, social and knowledge vulnerability
- New Zealand on ring of fire and plate boundary
- Haiti is also on a plate boundary
what is governance?
Governance is the sum of the many ways individuals and institutions manage common affairs. It is a root cause of vulnerability.
as developing countries generally have poor governance (root cause) what do they normally also have?
- Poor investment into social development, rapid urbanisation
- Exploitation of the environment (dynamic pressure)
- High inequality, poor building and infrastructure, lack of preparedness (unsafe conditions)
what is economic governance
includes the decision-making process that affects a country’s economic activities and its relationship with other economies. This has major economic implications for equity, poverty and QOL.
what is Political governance
is the process of decision making to create policies, influencing national disaster reduction and planning. The nature of this process and the way it brings together the state, non-state and private. Sector players determined the quality of the policy outcome.
what is Administrative governance
is the system of policy implementation and requires good governance at both central and local levels. It requires functioning enforcement of building codes, land-use planning, environmental risk and human vulnerability, monitoring and safety standards.
