Hazards Flashcards
What is a hazard?
Potential threat to life and property caused by an event.
They can be natural or caused by humans.
What are natural disasters?
Disasters occur when a vunerable population is exposed to a hazard.
Dregs model is a good representation of this concept.
What are the 3 main types of hazard?
Geophysical - tectonics, volcanoes
Atmospheric - weather systems, wildfires
Hydrological - bodies of water, floods
Can be a mixture of the 3
What is hazard perception
Viewpoints on how dangerous / how much of a threat a hazard poses to a group of people.
What lifestyle factors affect perception of hazard?
Wealth - may percieve hazard to be smaller as they are less vunerable. Equally, may view it as higher as cost of property damage and financial loss.
Experience - people who have experienced more hazards ar emore likely to understand the extent. Some may be more optimistic and unrealistic on the outlook. ‘Lightning never strikes twice’
Education - more educated will understand the effects - more likely to evacuate
Religion and beliefs - everything happens for a reason, don’t view hazard as negative. Strong environmental conservation belief may vire hazards as huge risk.
Mobility - limited access to evacuation - hazards greater threats in secluded locations. Impared with disabilities or illness
What is fatalism
Response to hazard that nothing can be done, hazards are uncontollable and should be accepted.
What are some active responses to hazards?
- prediction
- adaptation
- mitigation
- management coordinated strategies - prediction, adaptation, mitigation.
- risk sharing - community preparedness - community shares risk and invests collectively to mitigate future hazards.
Name an example of risk sharing that worked
New Zealand - multi-hazard environment under threat from earthquakes, tsunamis, volcanoes and atmospheric related hazards.
Canterbury EQ (2010) cost 20% gdp.
Name the aspects of hazards
Incidence - how often it occurs. Generally low incidence have higher magnitude. Harder to predict and more catastrophic.
Distribution - where they occur geographically. Areas of high hazard activity have management strategies. Pacific ring of fire - EQ and Volcanoes.
Intensity - power of hazard and how damaging the effects
Magnitude - size of hazard, usually how intensity is measured.
Level of developent- affects how well a place can respond to hazard. Ifentical hazards affect places different based on economical development. Multihazard environments struggle as resources spread thinly.
What is the difference between magnitude and intensity of a hazard?
Magnitude - definable by a number scale that doesn’t change.
Intensity - affect on person and can change depending on distance from hazard and management strategies in place.
Evaluate the effectiveness of hazard models.
Can they be applied to every hazard?
Does it take aspects of hazards into account?
Is there a timeframe?
Is the model too vague?
Doesit include hazards surrounding climate change?
Describe the structure of the earth.
Crust - top layer of lithosphere, oceanic crust is dense and continential is thicker but less dense. Oceanic crust is destroyed.
Lithosphere - majority within mantle.
Asthenosphere - semi-nolten layer moves due to concection currents - powered by heat from core.
Mantle - mainly solid rock high in silicon. Top layer semi-molten.
Outer core - semi-molton, mainly iron and nickel.
Inner core - solid ball of iron and nickel. Hot and extreme pressure - radioactive decay provides extreme heat.
What is the plate tectonic theory?
The lithosphere is broken into plates which move through convection currents in the asthenosphere.
State what happens at a destructive boundary for all 3 plate margins.
Oceanic-continental - dense oceanic plate subducts below continental. Ocean trench, fold mountains, explosive composite volvanoes form.
Oceanic-oceanic - heavier plate subducts. Island arcs formed by volcanoes, and trenches form here.
Continential-continential - neither subducts. Forms fold mountains.
State what happens at a constructive plate boundary. Include both types of plate margin.
Oceanic - oceanic - plates pull apart forming ocean ridge. Magma rises in gap forming new land. New land pushes slabs of magma away from ridge - ridge push.
Continental- continental- land pulls apart forming rift valley. Volcanoes form as magma rises through gap. Usually fills up with water forming separate island. Lifted areas called horsts, valley is called a graben.
Explain what ridge push and slab pull are.
Ridge push - slope created when plate smove apart causes plate to push further away through gravity. AKA gravitational sliding.
Slab pull - when plate subducts pulling rest of plate with it.
