Hazards 3.1.5.1 Flashcards
3.1.5.1-3.1.5.6
What is a natural hazard?
Natural hazard = A natural event with the potential to cause harm to people and to property
What is a natural disaster?
A natural disaster = The realisation of a natural hazard where harm has occured
When can a hazard be defined a disaster?
- 10 or more deaths have occured or when there is a declaration of an emergency by the relative government
- Insurance companies define it when economic losses exceed 1.5million
What can hazards be caused by?
- Human actions (explosions, chemical releases into atmosphere and nucler incidents)
- Natural (earthquakes, storms, volcanoes and wildfires)
- Natural events are often caused by human action e.g wildfires due to human carelessness
What factord affect the impacts of hazards?
-The location of rge hazard relative to areas of population and the magnitude and extent of the hazard
- Specifc to the type of hazard e.g. type and exposivity of a volcanoe, Nature and continental shelf and shoreline for tsunamis
What are geophysical hazard?
Geophysical= caused by the movement of tectonic plates, driven by the earths own internal energy
E.g. Plate tectonics, volcanoes, sesimic activity
What are atmospheric hazards?
Atmospheric = Caused by processes occurring in our atmosphere
E.g. Tropical storms, Droughts
What are hydrological hazards?
Hydrological = driven by water bodies, mainly the ocean
E.g. Floods, Storm surges, Tsunamis
What are primary impacts?
Primary impacts = Those that have an immediate effect on the affected area, such as destruction of infrastructure and contamination of water supplies
What are secondary impacts?
Secondary impacts = impacts that have occurred after the disaster has occurred such as disease, economic recession and contamination of water supplies
What is hazard perception?
Hazard perception = the way in which someone understands or interprets a hazard
What is hazard perception determined by?
- The effect that the hazard may have on our lives and this increases if people have a direct experience with a hazard and the long term impacts it caused
What are the negatives of urbanisation for hazards?
- The pressure of an increasing population and subsequent demand for land has resulted in building on areas that are at increased risk
Population expansion can increase the risk of a hazard
How are hazards percieved as advantageous to some people?
- some people make use of the fertile soils on floodplains or in the vicinity of a volcanoe can be considered a risk worth taking and living with the threat is accepted
What are the effects of diasters on HDES ?
HDES effects tend to do little long term damage to the economy as there is enough wealth and potential for redevelopment to br able to rebuild infrastructure and supporting those directly affected
What are the effects of disasters on LDES?
LDES are more reliant on support and aid both in the immediate aftermath of an event and also in the long term
What are the local level responses to a disaster?
Saving possessions, and safeguarding property
What are the global responses to a disaster?
Co-ordination rescue and humanitarian aid
The intensity and magnitude if the event as well as the original state of the infrastructure affects the spread of international response
What is the automatic disaster analysis and mapping system (ADAM)?
A database that pools informarion from the US geographical society, world bank and world food programme
It allows almost immediate access to such information as the scale of the disaster and what supplies are avaliablly localy
What is fatalism?
Fatalism = acceptance - a view that nothing can be done to mitigate the hazard and therefore the outcome and the loss will be inevitable
What is community prepareness/risk sharing?
Prearranged measures aimed at reducing the loss of life and property damage
Can be done throigh public education and awareness programmes, evacuation procedures and provison of the neccesary resucres before hazards occur
Prediction
The ability to give warnings so that action can be taken to reduce the impact of hazardous events
E.g. remote sensing and seismic monitoring, advances in communications and warnings communication promptly
Preparation
Prearranfed measures that aim to reduce teh loss of life and damage to property throuhh increased awareness
E.g. Buildings/infrasturtucre made to withstand gazards
Prevention
Trying to stop the natural hazard occurring at all (impossible)
Mitigation
Physical action that takes place to lessen the impact of a natural hazard
Adaptation
Changing behaviour or physical/natural environment to reduce the risk
What is hazard management cycle ?
Hazard management cycle = shows phases of response, recovery, mitigation and prepardness in the management of a hazard
- Shown as a 4 stage continuous model
- Each stage is linked to the next but will also be an overlap between the stages
- Cycle involves key players/stakeholders: the government (at all levels) international organisations (The UN, Aid agencies) Business and Community
Recovery
- In short term how can affected area regain its essential services to aid long term recovery - restoration of services so that longer term planning and reconstruction can begin
- In the long term how will impacted area return to normal
Response
- Speed will depend on the effectiveness of emergency resposne teams and level of prepardness
- Short term responses focus on saving lives
- Assesment of damage will determine level of recovery required
prevention & mitigation
- How can impact of an event be lessend e.g. retrofitting or firebreaks in area ro prove to wildfires
- Will they be short term /
- long term protection of natural barriers such as coral reefs which protect the shore against storm surges, support after disaster in form of aid and insurance and reduce long term impacts
- Will they be hard or soft engineered?
- How much aid assistance comes from overseas
- Communities may not be avaliable in all high risk areas even in HDES and not at all in LDES who need it the most
preparation
- Is the community ready for the next hazard ( education)
- Good preparation allows for a more effective response to another event
- High risk areas tend to be better prepared
What is parks repsonse model ?
Parks response model = shows the changing quality of life through different phases of a disaster
*steepness of downward curve during disruption depends on the nature of the event (volcanoes could have weeks of warning so be able to mitigate the impacts)
What is a multi hazard zone?
Multi hazard zone = an area which is prone to a range of hazards. Some of these may be interrelated such as earthquakes triggering a landslide
What is Deggs model?
Deggs model shows the relationship between vulnerability, hazards and disaster. He indicates the interconnectedness between physical and human factors of place (synopicity and varying rates of different players / stakeholders)
Vulnerability includes: population? Devloped?What is the land used for? Emegency services prepared?Infrastructure?
Natural Hazard : When did it last occur? How large was affected area? How long did it last? How big was the event? etc
What are root causes?
Root causes = human context of place. This affects the vulnerability of the population
High inequality will rate low on hdi <0.555- peoples needs are not being met
Means either higher chance of people being killed or higher chance of people being rescued
Resillence
Resilience = the ability of a system, community or society exposed to hazards to resist, absorb and accommodate to and recover from the effect of a hazard
Relief
Stage 1 - Relief
(hours-days)
● Immediate local
response - medical
aid, search and rescue
● Immediate appeal for
foreign aid - the
beginnings of global
response
Reeconstruction
Stage 3 - Reconstruction
(weeks-years)
● Restoring the area to
the same or better
quality of life
● Area back to normal -
ecosystem restored,
crops regrown
● Infrastructure rebuilt
● Mitigation efforts for
future event
Rehabilitation
Stage 2 - Rehabilitation
(days-weeks)
● Services begin to be
restored
● Temporary shelters
and hospitals set up
● Food and water
distributed
● Coordinated foreign
aid - peacekeeping
forces etc.
Risk sharing
Risk sharing = working together to reduce the risk and sharing the cost of hazard response
How many people died in haiti eq 2010?
200,000 people
Deaths were due to infrastructure collapses not the eq itself
Primary hazard
Primary hazard = happen immediatley and are caused by the energy released by the earth
Secondary hazard
Secondary hazards = happen as a result of the primary hazards
What is sea floor spreading?
Sea-floor spreading = Movement of oceanic crustal plates away from constructive plate margins
Who produced the idea of sea floor spreading and when?
-Harry Hess in 1962 and this helped support wegeners theory of continental drift
-Hess discovered that rocks increased in age with distance from mid ocean ridges and that new oceanic crust were therefore being formed when plates diverged
- Hess theory was backed by the magnetic dating of these rocks (paleomagnetism)
-
Facts about sea floor spreading?
- 12,000ft long mountain range formed as mid alantic ridge a ridge of underwater volcanoes
-Molten rock pushed up from inside earth at the ridge new crust new ocean floor - Rate of spreading is expected to be up to 5cm per year
What is paleomagnetism?
Paleomagnetism = Measurement of the magnetism preserved in older rocks
Facts about paleomagnetism?
-Approximatley every 400,000 years the earths magnetic field swtitch polarity between north and south
-Studies in 1960s of magnite ( iron oxide) produced from the balsatic lava along mid ocean ridge records the earths magentic orientation at that time
-Both age and magnetic orientation and symetrical suggesting that the oceanic crust is slowly spreading away from this boundary and therefore supporrs theory of contineyal drift
-
What is mantle convention?
Mantle convention = the rising and falling of magma within the asthenosphere
Facts about the asthenosphere
part of the mantle that lies directly beneath the lithosphere
Gravitational sliding
Gravitational sliding = the movement of tectonic plates as a result of gravity at mid-ocean ridges and deep sea trenches (ridge push and slab pull)
Ridge push
Ridge push = the higher elevation at an ocean ridge causes gravity to push down and drag crust away from the ridge
Slab pull
Slab pull = The process whereby , following subduction, the lithosphere sinks into the mantle under its own weight ‘pulling’ the rest of the plate with it