Hazards Flashcards
Black Saturday
7th February March 14th 2009
Series of fires that started over the course of a months
Causes
- area covers in eucalyptus which ignites easily aiding the fire explosive flammable fuel
- temperature peaking at 45.1 degrees C
- V low humidity
Heatwave and drought causes by El Niño and Indian Ocean Dipole
Impacts
- Kinglake fire = largest of many fires burning on Black Saturday destroying 1,800 houses
- 173 does
- 7000 displaced from homes
- 4.4 billion USD damage
- looting happened to abandoned properties
Mitigation and response
- More than 4,000 firefighting personnel mainly from CFA deployed
- bush fire appeal raised over 350 million USD
- fire breaks, bulldozing vegetation to break course of flames
- offered families therapy to deal with trauma
- replanted trees in burnt down areas (helps stabilise hills and prevent mud slides
- Aus gov released ‘rebuilding together’ scheme to replace major facilities damaged in the flames
- 80 millions relief funding over next 30 years from Aus government
Prevention of future fires
- can’t prevent natural hazard (debatable global warming)
- controlled managed burning= less dead dry vegetation but disrupts ecosystems
- public awareness ‘smokey bear’ educated people about leaving bbqs and campfires unattended to
- fire ban at times of high risk
Example of earthquake ? Poor
Hati
- 13th Jan 2010
- in Caribbean
- lies between two fault zones, conservative play boundary (NA plate and Caribbean plate)
- fatalistic perception
- 70% live on 2 dollars or less a day
- life expectancy in Hati
- 7 on Richter scale
- epicentre 25km of Port au Prince
- 52 after shocks above 4.5
Perception
- fatalistic
- 86% live in slums
Cause
- Epicentre close to capital
- few earthquake resistant buildings
Primary impacts
- 220,000 dead
- several hospitals collapsed
- airport damaged
- businesses destroyed
- gas mains ruptured
secondary impacts
- 1 in 5 lost their jobs
- 1.3 homeless
- morgues overflowed with dead bodies = contamination in street of Hati= cholera outbreak
- aid obstructed as airport damaged
- many months later cholera outbreak and has killed 10,000 since event
Primary responses
- emergency rescue teams from Iceland
- 8000 temporary field hospitals set up by Red Cross
- UN troops and police sent to help distribute aid
- 100 mill given by USA
Secondary responses
- money pledged by organisations and governments but slow progress
- but after 1 year
1 mill still without a home
Cash for work programmes, still rubble
Schools being rebuilt and teachers trained
Volcanic activity example ?
Eyjafjallajokull
Iceland
On huge fissure
- on a Atlantic ridge
- April 2010
- constructive divergent plate boundary
- 4 VEI scale
Causes
- 2 bodies of magma meeting
Primary impacts of eruption
- ice cap melted on volcano = mass flooding
- pyroclastic flows
- interaction of water and gas= explosive plume of gas + volcanic ash caught in high altitude winds 10km high then carried south east
- deaths
- destruction of main roads
Secondary impacts of eruption
- air spaces in Europe which meant all air space shut down temporarily
- 100,000 flights cancelled effected tourism and trade
- 25% increase in respiratory illness across Iceland
- 11% decline in tourism following eruption
- fertile soils reported record yields following year
- coach and cruise ship companies benefited helping get people home
Primary response
- due to constant monitoring of the volcano sites the IVO suggested all people on the southern coastal towns be evacuated
- live stock moved
- sections of embankment deliberately breached to allow flood water to run to the sea and preventing expensive bridges being destroyed
- successful response as no one lost their lives
Secondary responses
- had to import more food as large areas of land not fit for agriculture
- ‘future volc’ improves technology and sensors so Icelandic officials be prepared in event of another eruption
- rebuilding damaged infrastructure
- Eyjafjallajokull = no popular tourist site= brings thousands in
- air fares increase to recoup losses
- families had to temporarily relocate
- research aims to improve forecast methods
Tropical storm example ?
HIC
USA Hurricane Katrina
Formed 200 miles SE of Bahamas
Caribbean sea around 28*c
-intensified to category 5 exceeding wind speeds of 175mph
-late August hit New Orleans
New Orleans
-high density population due to urbanisation
Advances warning given out on 26 August
- mayor or New Orleans ordered city be evacuated shortly after Kathrine was upgraded to cat 5
Primary impacts
Storm surge hitting Louisiana 10m high Desiree’s gulf coast
- more than 1 million became refugees
- demolished 30 oil platforms
- effected breeding grounds of endangered species e.g brown pelican
- Louisiana super Dome overcrowded, capacity 800 and 30,000 showed up= rape and crime
- 1.8 k died= low death toll as USA has good infrastructure
Secondary impacts
- refugees still in all 50 states
- racial tensions exposed
- oil prices rose, uk petrol increase by £1 per litre
- 200 billion USD damage
- businesses failed as couldn’t pay for damages
Primary responses
- most population left in cars
- 150 thousand remained, mainly by choice and arguably poorer who may not have had home insurance (illustrates how behaviour responses are determined by potential economic losses
- 1.8 billion donated to American Red Cross
- troops sent out to keep law and order
- Louisiana super dome offered as shelters
Secondary responses
- state criticises for poor effort for planning for event
- most effected by Katrina of black ethnicity and urban dwellers (poorest and most disadvantaged) in American society
- alleged authorities would have responded differently had it been white people majority effected by Katrina
What is a hazard
Threat of substantial loss of life that substantially impacts life and property that’s caused by an event either naturally caused or through humans
What is a disaster?
Is a result of a hazard, e.g living on a fault line= hazard but the earthquake effecting property and people is a disaster
What is a risk?
Exposure of people to hazardous event presenting a potential threat to themselves
Vulnerability ?
Potential for loss
Mitigate ?
Any sustained action to reduce/ eliminate risk of life/ property
3 types of hazard ?
Geophysical- driven by earths internal energy
Atmosphere- driven by processes in the atmosphere
Hyrdrological- driven by water bodies
Common features of hazards ?
- origins clear
- allow short earning before event
- requires emergency response
- results in loss of life
Resilience?
Capacity?
Community preparedness?
Resilience- ability of communities/ individuals to respond/ recover effects
Capacity- resources and strengths within a community that help them withstand/prepare for mitigate/ prevent/ recover from natural disaster
Community- prearranged measures that aim to reduce the loss of life and property damage through e.g education and food and shelter supplies
Explain the hazard management cycle ?
- illustrates the process which governments plan for and reduce the impact of natural disasters, following stages correctly results in greater future preparation and practical action company used this model
4 sections of the cycle?
(2 pre-event, 2 post event)
- preparedness, education and awareness can reduce human causes and adjust behaviour to minimise likely impact of a hazard
- response, speed of a response depends on effectiveness of emergent plan put in place
- recovery, restoring affected area to something approaching normal
Mitigation, actions aimed at reducing the severity of an event
Describe park impact response model
Describes 3 phases following a hazard
Relief
- immediate response in form of aid, expertise, search and rescue
Rehabilitation
- infrastructure restored temporarily to allow construction phase to begin
Reconstruction
- restoring to same or better quality of life as before event took place, likely to include measures to mitigate against similar level of disruption of event occurs again
2 types of plate ? And their characteristics?
Oceanic-
- basaltic rock, thinner but more dense
- 200 million yrs old
Continental
- granitic rock, thicker and less dense than oceanic
- 1.5 billion years old
- won’t sink into asthenosphere
What’s the Mohorovic discontinuity
The sharp divide between the upper mantle and crust
Lithosphere ?
Crusts and upper mantle where tectonic plates are formed
Asthenosphere?
Upper part of mantle and below lithosphere
What causes the earths magnetic field ?
Spinning of the outer core when the inner core rotates
2 species of internal heat on our planet ?
Radiogenic- heat created by radioactive decay of isotopes
Primordial- heat left over from initial collision during formation of the the earth
Evidence for continental drift as proposed by Alfred Wegener ?
Geological- minerals and striations match on different continents e.g Brazil and West Africa suggesting they were once pieces together
Climatological- glaciation in Africa, America and other countries all at same time around 300 millions years ago
Biological
- fossils of same species found in different continents separated by seas and plants e.g mesosaurus
Criticise Alfred Wegener theory
- no mechanism for movement
- wind and currents could carry species of plants/fossils across seas
- theory wasn’t accepted by scientists at time
Harry Hess’ plate tectonic theory ?
Studied age of rocks in Atlantic Ocean, confirmed newest rocks were in center of ocean and still being formed
(Said Atlantic ridge could be widening by 10cm a year)
Strength of Harry Hess ?
We can measure plate movement through palaeomagnetism, scientists know the approx flip of earths magnetic field and using positions of the ions in the rocks we can find out the rate of movement in plates
3rd body of evidence for plate movement ?
US when testing nuclear weapons underground uncovered idea of rigid plates and set up network of seismic stations and produced a coherent theory of plate tectonics
What is ridge push ? As an alternative explanations for plate movement
Happens as constructive plate boundaries, upwelling at ocean ridges. Gravity abuses these ridges to slide down the moving plate
What is slab pull ?
At destructive plate boundaries gravity pullls the whole oceanic plate down = destructive subduction
What happens at oceanic continental convergence
Continental oceanic
Denser oceanic plate subducts under continental = oceanic trench e.g Peru Chile trench
-the continental land mass is uplifted and compressed creating fold mountains e.g Andes
- friction builds at Benioff zone, earthquake may release tension
- melted oceanic plate is less dense that surrounding magma and may find its way to surface through faults in oceanic plate = explosion be volcanic eruptions
What happens at oceanic oceanic
?
Convergence
Faster/denser plate subducts dcreatjng deep ocean trench, melting of oceanic plate = magma plumes = summarise volcanoes that may turn to island arcs e.g Mariana Trench and Mariana Islands
What happens at continental continental plate ?
Low density so subduction doesn’t occur, colliding plates create high food mountains e.g Himalayas
Rift valleys are ?
During continental divergence lithosphere stretches = fracturing into set of parallel fault lines
- land between these faults collapses into valleys e.g Great African Rift Valley
Mid-ocean ridges ?
Divergence at continental areas creates chain of sub-marine mountain ridges e.g Mid Atlantic Ridge, middle of ridges are marked by deep rift valleys
Valleys widened by rising nagana that cools and solidifies
- volcanic eruptions occur along ridges creating sub-marine volcanoes
