Hazards Flashcards
(33 cards)
HAZARDS IN A GEOGRAPHICAL CONTEXT
What is a natural hazard? Give as many examples as you can.
natural hazard: the threat of substantial loss of life, impact upon or damage to property caused by an event.
e.g.) earthquakes, volcanic eruptions, wildfires, hurricanes, floods, tsunamis, droughts, landslides
HAZARDS IN A GEOGRAPHICAL CONTEXT
Outline, explain and exemplify the three categories of hazards.
Geophysical (tectonic) - driven by the earth’s internal energy sources
e.g.) volcanoes/volcanic eruptions, earthquakes, tsunami
Atmospheric (weather) - driven by processes occurring in the atmosphere
e.g.) tropical storms
Hydrological - driven by bodies of water
e.g.) floods, droughts
PERCEPTION OF HAZARDS
Define ‘risk’ and ‘vulnerability’, then give 5 reasons why people choose to live in hazardous areas.
risk - the exposure of people to a hazard which could threaten their lives, their possessions or their property.
vulnerability - the potential for loss
- unpredictability (frequency, magnitude, location)
- lack of alternatives (social, political, economic factors)
- changing levels of risk (places that were once safe are now risky)
- cost-benefit (fertile soil, geothermal energy)
- perception or naïvety
PERCEPTION OF HAZARDS
Explain how hazard perception has economic and cultural determinants. (What affects a person’s perception of hazards? Give 6 factors.)
CHECK
- socio-economic status
- level of education
- employment status
- religion/cultural background
- family situation
- past/lived experience, age (e.g. older people may have less fear of death since they’ve lived a long life)
PERCEPTION OF HAZARDS
Which 5 factors could affect or change the impacts of a natural hazard?
- location of hazard (HIC/LIC, country/urban/rural)
- size of the population (densely/sparsely populated)
- magnitude/strength/category of event
- level of development
- level of preparation
PERCEPTION OF HAZARDS
Explain the fatalism approach as a human response to hazards.
fatalism (aka acceptance)
- an acceptance that hazards are natural events that we can do little to control and losses must be accepted. the idea that natural hazards are “an act of God”
- the view that interfering with natural processes and natural environments (to try and stop a hazard) could be detrimental to the environment
- also, it can be argued that hazards can act as a regenerative process and so they should be allowed to take their course (positive thing)
PERCEPTION OF HAZARDS
Explain the prediction approach as a human response to hazards.
prediction
- the view that hazards are predictable to some extent, which can reassure people and reduce fear around hazards
- as technology increases/improves, we will become better at predicting and monitoring hazards, leading to improved communications and warnings to people most at risk
- more likely to be the perception in more developed countries due to money, infrastructure and skills
PERCEPTION OF HAZARDS
Explain the adjustment/adaptation approach as a human response to hazards.
adjustment/adaptation
- accepting that natural events are inevitable and adapting our behaviour accordingly to reduce losses
- people see that they can prepare for hazards by adjusting systems, responding flexibly to the hazard and researching into new technology to help mitigate the hazard
- the most realistic option for many people and is the most effective and cost-effective for governments (esp. less developed countries due to less income for research etc.)
HAZARD MODELS
Define and sketch the Hazard Management Cycle.
the hazard management cycle illustrates the ongoing process by which governments, businesses and society manage both the pre- and post- hazard event situations.
(in a circular cycle:)
(hazard event) –> response –> recovery –> mitigation –> preparedness –> (hazard event –> response etc.)
HAZARD MODELS
Explain each section of the Hazard Management Cycle.
- recovery: reacting to a hazard event (speed of response depends on effectiveness of emergency plan put in place) (e.g. immediate responses focus on saving lives)
- recovery: restoring the affected area back to normality (or as close as it can be) (e.g. restoring vital services so long-term planning can occur)
- mitigation: reducing the severity of the event and lessening its impacts (next time around) (e.g. changes to building design or building defences)
- preparedness: education and awareness can minimise the likely impacts of a hazard event, even though the hazard cannot be prevented from happening. in areas of higher risk, the level of preparedness will often be greater than in areas of lower risk.
HAZARD MODELS
Define the park model of human response to hazards.
the Park model illustrates the stages an area goes through over a period of time, before the hazard, during the hazard and after the hazard. It also considers the effect the hazard has upon quality of life.
HAZARD MODELS
What 3 factors cause each stage of the Hazard Management Cycle to vary?
- the magnitude/strength of the event
- the wealth/level of development in the area
- the help available, e.g. government or external help
HAZARD MODELS
What are the 3 phases following a hazard event that the park model describes? Describe each one.
- relief: An immediate aid (local or global) in the form of aid, expertise and search and rescue
- rehabilitation: A longer phase lasting weeks and months, whereby key infrastructure and services are mostly repaired (starting to get back to normality)
- reconstruction: Restoring or rebuilding to the same of better quality than before the event took place. May include mitigation measures to prevent the same level of disaster occurring again.
HAZARD MODELS
What 3 factors would change parts of the park model?
the wealth/development of the country
the level of preparedness/mitigation
the strength/magnitude of the hazard
HAZARD MODELS
Comment on the relationship between human responses on the Park model and hazard incidence, intensity, magnitude, distribution and levels of development.
CHECK
HAZARD MODELS
Finish these sentences about the Park model:
The steepness of the downward curve depends on the…
The depth of the downward curve reflects the…
The gradient of the upward curve depends on the…
The steepness of the downward curve depends on the… nature of the event (i.e. wat hazard was it?)
The depth of the downward curve reflects the… scale of the event
The gradient of the upward curve depends on the… level of development and governance (provided both internally and externally)
HAZARD MODELS
Give 3 strengths and 3 limitations of the Park model.
STRENGTHS:
- visually effective and quite easy to interpret
- enables comparison of different events
- highlights significance of emergency relief and rehabilitation in the aftermath of hazard events
LIMITATIONS:
- generalised and not necessarily applicable to all areas in the world
- doesn’t account for different levels of development in a country
- no account for varying capacity to respond (doesn’t consider that some countries need more outside help than others)
STRUCTURE OF THE EARTH
Sketch the Earth’s structure including the depths and description of layers. Include: thickness of layer, state (i.e. solid/liquid) and key characteristics.
layers to include:
CRUST
- outer layer
- thickness: 5-10km beneath oceans
- state: solid
- key characteristics: oceanic crust = occasional broken layer of basaltic rock (sima = silica and magnesium). continental crust = bodies of mainly granite rocks (sial = silica and aluminium)
LITHOSPHERE: the crust and the upper mantle, the zone where the tectonic plates are found.
ASTHENOSPHERE: the semi-molten, plastic-like material/rock below the lithosphere on which the tectonic plates float
MANTLE
- second layer
- thickness: 2900km thick
- state: liquid
- key characteristics: mainly silicate rocks due to great heat and pressure
OUTER CORE
- third layer
- thickness: 2250km
- state: semi-liquid
- key characteristics: mainly iron
INNER CORE
- central layer
- thickness: 1200km
- state: solid
- key characteristics: iron-nickel alloy, source of earth’s internal heat (due to natural radioactive decay), which is a major cause of the earth’s tectonic activity
STRUCTURE OF THE EARTH
Differenciate the two types of crust based on:
- thickness
- density and light/heavy
- age of rock
- types of rock its made out of
- sima or sial
CONTINENTAL
- thickness: 35-40km thick, 60-70km under mt chains
- density and light/heavy: lighter, denstity of 2.7g/cm3
- age of rock: very old, mainly over 1500 million years
- types of rock its made out of: mostly granite
- sima or sial: sial
OCEANIC
- thickness: 6-10km thick
- density and light/heavy: heavier, density of 3.0g/cm3
- age of rock: very young, mainly under 200 million years
- types of rock its made out of: mainly basaltic (think salt, salt found in ocean)
- sima or sial: sima
PLATE TECTONIC THEORY
Explain plate tectonic theory and who came up with the idea first.
plate tectonic theory: Alfred Wegner in 1912
- the world was once a super continent called Panagea (300 million years ago)
- then Panagea broke into Laurasia and Gondwanaland
- continents look the way they do today because of ‘continental drift’
PLATE TECTONIC THEORY
Outline ‘continental fit’ as evidence for continental drift.
It is not a coincidence that the continents such as South America fit very neatly into West Africa.
PLATE TECTONIC THEORY
Outline ‘geological evidence through glacial deposits’ for continental drift.
Evidence of glacial depositis in South America, Antarctica and India cannot be explained by their current location; they must have been formed together and then moved over time.
Rock striation patterns (scratches from glaciers moving over rock/surfaces) in Brazil are also similar to those in West Africa which points to a smiliar scenario.
PLATE TECTONIC THEORY
Outline ‘biological/fossil’ evidence for continental drift.
Mesosaurus remains were found in Southern Africa and South America, two far away places. It’s unlikely that it would have lived in both places and it was a freshwater animal so it wouldn’t have been able to swim across the Atlantic, indicating the two continents used to be joined together.
PLATE TECTONIC THEORY
Outline ‘climate evidence’ for continental drift.
Coal deposits that would have had to be formed in tropical climate conditions are found in places that do not now have tropical conditions (Antarctica), which means these plates must have moved over time.
