hazards Flashcards
what is a hazard?
a natural phenomenon that might have a negative effect on people or the environment.
in orrder for a physical event to be hazardous, what must there be?
a loss of life.
what is a geophysical hazard, and examples?
a natural hazard where the casual factor is a geological or geomorphological process.
- earthquakes,
- volcanoes,
- landslides,
- tsunamis.
what is an atmospheric hazard, and examples?
a natural hazard where the casual factor is an atmospheric process.
- tropical storms,
- tornadoes,
- droughts,
- wildfires.
what is a hydrological hazard, and examples?
a natural hazard where the casual factor is a water process.
- flash floods,
- avalanches.
what are the three examples of hazard perception?
- acceptance,
- domination,
- adaptation.
hazard perception - what is acceptance?
people seeing hazards as a natural event which are a part of life.
hazard perception - what is domination?
people understanding extreme events like hazards and being able to predict it.
hazard perception - what is adaption?
mixture of acceptance and domination. natural hazards will happen due to natural and human factors, and magnitude and frequency can be estimated.
how does hazard perception vary globally?
developed countries are more likely to be around ‘domination’ due to money and technology.
less developed countries use acceptance and adaption.
what are common characteristics of human responses to hazards?
fatalism, prediction, adjustment, mitigation, management and risk sharing.
human responses - what is fatalism?
where people accept there is a risk but choose to do little about it.
human responses - what is prediction?
predicting the occurrence in preparing places for the impact.
human responses - what is adjustment?
regular hazards are likely to be adapted to by people.
human responses - what it mitigation?
action to reduce or eliminate the long-term risk to human life and property.
human responses - what is management?
identifying the possible risks to human life and property, allocating resources to tackle the hazard.
human responses - what is risk sharing?
sharing knowledge and human response strategies will enable all countries to prepare for a hazard event in a better way.
what factors affecting the type of response taken to a hazard?
- psychology of population,
- magnitude,
- population,
- frequency,
- intensity,
- wealth,
- nature of the area,
- level of development.
type of response - what is distribution?
refers to the spatial coverage of the hazard, can also refer to the areas where the particular hazard is likely to occur.
type of response - what is frequency?
the distribution of the hazard through time.
type of response - what is magnitude?
assesses the size of the impact, or the energy released.
what is the park model?
a disaster response curve, to show the effects of hazards on the quality of life.
what are all the stages to the park model?
- pre-disaster phase,
- relief phase,
- rehabilitation phase,
- reconstruction phase.
how can different events have different impacts? (variations)
- the speed of the drop in quality of life,
- how far quality of life drops,
- the duration of the decline,
- the speed and nature of recovery.
what is the nature of recovery related to?
- the need to reduce vulnerability,
- the desire to increase self-reliance,
- goal of restoring normality as soon as possible.
what happens during the relief phase?
teams arrive from outside the immediate area, to help with search and rescue.
what happens during the rehabilitation phase?
assessment of needs and coordinated planning of resources.
what happens during the reconstruction phase?
permanent changes are introduced to restore quality of life.
what are the four stages of the hazard management cycle?
- preparation,
- response,
- recovery,
- mitigation.
hazard management cycle - what is preparation?
includes plans or preparations made in advance of an emergency. e.g public education or rehearsals.
hazard management cycle - what is response?
includes any action taken in the midst of or following an emergency. e.g evacuation or s&r.
hazard management cycle - what is recovery?
includes restoring and rebuilding the impacted area. e.g temporary housing or public information.
hazard management cycle - what is mitigation?
includes implementing measures to prevent future risks and disasters. e.g flood proofing or insurance.
how can globalisation help with tackling disasters?
- movement of money,
- transport developments,
- trade links,
- communication.
how is there a lack of consistency around global response?
- political alliances,
- stages of development of countries,
- levels of corruption,
- internal conflicts.
what are the characteristics of the core?
- made up of dense rock,
- divided into solider inner and molten outer,
- convection in the outer core gives rise to the earth’s magnestic field.
what are the characteristics of the mantle?
- made up of molten and semi-molten rocks,
- deep as 2890km,
- rock rich with iron and magnesium.
what are the characteristics of the crust?
- crust is lighter because it contains silicon, oxygen, aluminium, potassium and sodium,
- composed of igneous rock,
- less 1% of earths volume,
- crust separated from the mantle by the Moho discontinuity.
what are the characteristics of oceanic crust?
- beneath deep oceans,
- between 5-8km,
- consists of basalt rocks less than 200 million years old.
what are the characteristics of continental crust?
- beneath earth’s continental land masses and under shallow sea, between 30-70km, consists of lighter rocks both young and 4 billion years old.
what is the upper mantle and crust divided into?
lithosphere and asthenosphere.
what is a super-continent?
a large landmass made up of most of or all of earth’s land.
who created the theory of plate tectonics?
wegener.
what is the plate tectonic theory?
the outer rigid later of the earth is divided into a couple dozen plates that move across the earth’s surface relative to each other.
what is the evidence that continents were joined together?
- fitting together,
- fossil evidence,
- glacial deposits,
- geological evidence,
- mountain belts,
- sea floor.
what are the three plate movements?
- constructive - moving apart,
- conservative - moving past,
- destructive - moving towards.
what are the two main types of forces that influence plate motion?
friction and gravity.
plate movement - what is basal drag? (friction)
plate motion driver by friction between the convection currents in the asthenosphere.
plate movement - what is slab suction? (gravity)
plate motion driven by local convection currents that exert a downward pull on plate in subduction zones at ocean trenches.
plate movement - what is slab pull?
the denser plate sinks back into the mantle under the influence of gravity, then pulls the rest of the plate behind it.
plate movement - what is ridge push?
magma rises as the plates move apart, the magma cools to form a new plate. when it cools is becomes denser and slides down away from the ridge.
what is a constructive plate margin?
- plates move away from each other,
- causes volcanoes,
- causes weak earthquakes,
- two continental or two oceanic.
what is a destructive plate margin?
- plates move towards each other,
- causes volcanoes,
- causes earthquakes,
- oceanic + continental = oceanic subducts,
- continental + continental = mountains.
what is a conservative margin?
- plates moving past each other,
- no volcanoes,
- causes earthquakes.
