Hazards Flashcards
what is a hazard by definition?
potential threat to human life and property caused by an event.
what is a natural disaster?
when a vulnerable population is exposed to a hazard
who’s model represents hazards and disasters?
Degg’s model
what are the three main types of geo hazard?
geophysical- land processes
atmospheric- atmospheric processes- weather
hydrological- water bodies and movement
what are hazards that are both atmospheric and hydrological?
hydrometeorological hazards
what can cause people to have different viewpoints of how dangerous hazards are and what risk they impose?
- lifestyle
- £
- cultural
how can wealth effect affect how a person might perceive a hazard?
wealthier people may perceive a hazard to be smaller as they are less vulnerable. yet they may also see the risk as greater as there is more risk of property damage and financial loss.
how can experience affect someones hazard perception?
someone who has experienced more hazards more likely to understand full effects of hazards. OR have a ‘lightening never strikes the same place twice’ mindset
how can education affect someones hazard perception
?
A person who is more educated about hazards may understand their full effects on people and how devastating they can be and have been in the past.
how can religious beliefs affect someones hazard perception?
Some may view hazards as put there by God for a reason, so may not perceive them to be negative.
how can mobility affect someones hazard perception?
Those who have limited access to escape a hazard may perceive hazards to be greater threats than they are
what is fatalism?
- uncontrollable natural events
- any losses should be accepted
- nothing that can be done to stop them
“what ever happens happens”
what are 5 active responses to hazards?
RAMMP
- prediction
- adaption
- mitigation
- management
- risk sharing
what is prediction?
using scientific research and past events to know when a hazard will take place, send out warnings, impacts reduced
what is adaption?
attempting to live with the hazards by adjusting lifestyle choices so vulnerability is lessened
what is mitigation?
strategies carried out to lessen the severity of hazard
what is management?
coordinated strategies to reduce a hazards effects. includes (prediction, adaption, mitigation)
what is risk sharing?
community preparedness, community shares risks, invests collectively to mitigate the impacts of future hazards
give a case study of where risk sharing has worked?
New Zealand- Multi hazard environment (earthquake, volcano, tsunami), Canterbury hazard cost 20% of national GDP, now risk share by insurance investment so strategies can be put in-place before the disaster.
what is incidence?
frequency of a hazard, not affected by strength
what is an issue with low incidence hazards?
harder to predict and have less management strategies put in place = more catastrophic.
some characteristics of low incidence hazards?
- usually more catastrophic/ intense, only 36 earthquakes since 1500 were a magnitude of 8.5+ but millions of earthquakes that are too weak to be recorded.
what effects will have high magnitudes, high intensity hazards have?
worse effects require more management
are magnitude and intensity interchangeable?
NO
why are magnitude and intensity not interchangeable?
the magnitude is usually definable and can be a number- THIS DOES NOT CHANGE.
Intensity is effects on a person and can change dependent on distance from hazard or management strategies
how level of development effect how a place reacts to a hazard?
LIC= less effective mitigation strategies= efforts= more catastrophic
HICS that are less prepared= lack of management strategies
case study for a HIC not being prepared for a hazard?
Canada, where wildfires have been increasing less money and resources have been available for earthquake and tsunami preparation. even detailed Evacuation routes and tsunami siren are not available in pop tourists beaches such as Vancouver island. Text message systems are available tho.
what is the pate tectonic theory?
the lithosphere us broken up into large slabs of rock called tectonic plates
why do the plates move?
due to convection currents in the asthenosphere, which push and pull plates in different directions. convection currents are caused when less dense magma rises, cools, then sinks
what are the three types of plate boundaries?
constructive (away from each other)
destructive (towards each other)
conservative (parallel to each other)
what land forms are created at constructive (continental)
- rift valleys
- earthquakes
- volcanoes
what land forms are created at constructive (oceanic)
- ocean ridges
- earthquakes
- volcanoes
what land forms are created at conservative plate boundaries?
earth quakes
what land forms are created at destructive (continental)
- fold maintains
- earthquakes
what land forms are created at destructive (oceanic)
- ocean trenches
- island arcs
- earthquakes
- volcanoes
what land forms are created at destructive (continental/oceanic)
- fold maintains
- volcanoes
what are destructive plate boundaries?
oceanic crust sub-ducts under the continental plate. leaves a deep ocean trench.
what are the three different types of destructive plate boundaries?
continental and oceanic
oceanic and oceanic
contiental and conteinetal
what are the two types of plates at constructive plate boundaries?
oceanic and oceanic
continental and continental
what are two forces that inflencent how convergent boundaries occur?
rideg push
slap pull
what happens at a conservative plate boundary?
- parallel plates move in different directions
- the oceanic crust movement can displace a lot of water
- continental crust, fault lines occur where the ground is cracked by movement.
what are hotspots?
areas of volcanic activity that are not related to plate boundaries. Hot magma plumes from the mantle rise and burn through weaker parts of the crust. create volcanoes and islands. plame stays in same place but plates continue to move with sometimes cause a chain of islands
what happens on plate boundaries where volcanoes form?
plates melts and magma erupts through plate
name three hazards associated with volcano eruptions? LMT
lava flows- silica makes lava viscous and slow, common inn explosive eruptions
mudflows- caused by ice melting at high latitudes
tephra - any type of rock that is ejected by a volcano
what is the ring of fire?
an area of high volcanic and earthquake activity located in the pacific and the majority of large volcanoes occur within 25,000 mile belt
what is vulcanicity measured in?
volcanic explosivity index (VEI)
what are intense high magnitude eruptions known as?
explosive
what are calmer, lower magnitude eruptions known as?
effusive
what are the three classifications of volcanoes known as?
active, dormant or extinct
how many volcanoes erupt each year? estimated?
50-60
where are eruptions similar and regular?
on each type of boundary
can you definitely predict volcanoes? if not what can you use to predict?
NO, but seismic activity, gases releasing, and elevation indicate and imminent eruption
what are the primary/ secondary environmental effects of volcanoes?
ecosystems damaged
volcanic gases contribute to greenhouse effect
what are the primary/ secondary economic effects of volcanoes?
businesses destroyed
lost jobs
what are the primary/ secondary social effects of volcanoes?
people killed
trauma
what are the primary/ secondary political effects of volcanoes?
- gov buildings destroyed
- conflicts concerning government response to food
what are the four ways to respond to a hazard?
prevention
preparedness
mitigation
adaption
how can volcanoes be prevented?
- volcanoes cannot be prevented
- only thing that can be prevented is keeping people away from volcanoes
what can be done to be prepared for a volcanic hazard?
- monitoring, means warnings can be given out
- evacuation procedures planned
how can you adapt to volcanic hazards?
move away from risk area
or capitalise opportunities such as encouraging tourism
definition of a tropical storm?
a low pressure spinning storm with high winds and torrential rain
what are the 5 certain conditions for a tropical storm to form and develop?
- temperature
- air pressure
- wind shear
- rotation
- a trigger
what are the temperature conditions for a tropical storm to develop?
ocean temperatures must be around 26-27 degrees and 50m deep. warm water= energy
what are the air pressure conditions for a tropical storm to develop?
must be in areas of unstable air pressure (high pressure and low pressure meet (convergence))
what are the wind shear conditions for a tropical storm to develop?
winds must be present for the swirling motion to form
what are the rotation conditions for a tropical storm to develop?
tropical storms only form around the equator but no less than 5 on either side.
Coriolis effect= effect of earths rotation on weather events, there is no Coriolis effect at the equator
what are the trigger conditions for a tropical storm to develop?
spot of very high sea surface temperature, an area of low pressure
what is the formation of a tropical storm
1) warm moist air rises, leaving an area of low pressure below.
2) warm air rises and cools condensing into thunderstorm clouds
3) constant additions of energy from warm air causes storm to spin faster. at 39 mph= tropical storm
what is the eye of a tropical storm?
centre, calm and could free
what is the eye wall of a tropical storm?
most intese powerful area of the storm. Warm, most air rapidly rises here, high winds and torrential rain
what is the wind speed when a tropical storm can be classes at a hurricane/cyclone or typhoon?
74mph
what happens when a tropical storm reaches the coast?
the low pressure and high pressure winds will cause a large amount of sea water to be taken into the system, and released as a high wave called a storm surge
what happens when the storm then reaches land?
no longer has a supply of energy and the eye eventually collapses. heavy rain may persist for days
plates do not perfectly fit into each other, what does this mean happens at the plates?
plates become stuck due to friction between plates
what happens when a plate gets stuck?
pressure released = jolting motion= seismic movement= waves in ground
where is the epicentre?
directly above the focus
what is seismicity measured in ?
logarithmic richter scale (mag)
mercalli intensity scale (impacts)
logs moment magnitude (energy)
name two hazards that are caused by seismic events?
- shockwaves
- tsunami
what are shock waves?
When two plates move side by side, friction builds up and pressure increases when released vibrates throughout the ground
how do tsunamis occur?
-earthquake rocks ocean floor
-water pushed up
-sets of oscillation which develops underwater at great speed
-sea water is sucked back from the shore
waves get bigger as water gets shallower
what is liquefaction?
when soil is saturated, the vibrations of an earthquake cause it to act like a liquid. soil= weaker and more likely tp subside when it has large weight on it
what are the environmental primary/ secondary effects of seismic hazards?
p- fault lines
s- radioactive materials leaked from power plants
what are the economic primary/ secondary effects of seismic hazards?
p-businesses destroyed
s- economic decline
what are the social primary/ secondary effects of seismic hazards?
p- buildings collapse killing people
s- water supplies contaminated
what are the political primary/ secondary effects of seismic hazards?
p- gov buildings destroyed
s- political unrest from food shortages
what forms of prevention is there for seismic hazards?
- earthquakes and tsunamis will occur regardless
- liquefaction can be prevent through soil stabilisation
what are 2 forms of preparedness is there for seismic hazards?
- earthquake prone areas have extensive awareness strategies and eduaction in place
- tsumani warning systems
- evacutaion plans
what forms of mitigation is there for seismic hazards? 3
- search and rescue
- demolishing old unsafe buildings
- sea walls and tsunami wave breaks
what forms of adaptation is there for seismic hazards? 2
- move away from area at risk
- earthquake proof buildings
how are tropical storms measured?
saffir- simpson hurricane wind scale
name 4 hazards caused by tropical storms?
high winds- over 300km/h
flooding- storm surges/heavy rain
landslides
storm surges- rise in sea levels
what are the environmental primary/ secondary effects of storm hazards?
p- beaches erode
s- animals displaced
what are the economic primary/ secondary effects of storm hazards?
p- businesses destroyed
s- rebuilding and insurance payout
what are the social primary/ secondary effects of storm hazards?
p- drowning
s- homelessness
what are the political primary/ secondary effects of storm hazards?
p- government buildings destroyed
s- issues paying back International aid
what forms of prevention is there for storm hazards?
cannot be avoided
what forms of preparedness is there for storm hazards?
- evacuation plans
- storm warnings
what forms of mitigation is there for storm hazards? 2
- search and rescue
- clearing loose debris before storm
what forms of adaption is there for storm hazards?
- design buildings to stand high winds
- flood defences
WILDFIRES-
what are wildfires?
a large, uncontrolled fire that quickly spreads through vegetation
how can vegetation favour intense wildfires?
thick, close together vegetation allows fire to spread quickly and easily. Flammable oils like eucalyptus causes more intense fires
what fuel vege characteristics are there that favour intense wildfires ? 3
- vegetation should be dry to allow it to catch,
- finer vege causes fires to spread quicker
- large thicker vege burns for longer and more intensely
where are the most common wildfires? top 4 count
USA, Canada, Australi, Africa
what climates do wildfires occur in?
climates that have enough rain fall for sufficient plant growth, but considerate dry spells and droughts to dry out the fuel
give an example of dangerous winds that caused more wildfire damage?
Santa Ana winds and diablo winds California
what other climatic affects do el Nino and el Nina have on wildfire prevalence?
el nino (warm phase)- warmer wetter seasons to grow vegetation el nina (cold phase) dryer seasons create more wildfires
in recent times what has caused an increase in the number of wildfires?
temperature increase
what is happening to WF in W US?
- occurring 5x more often since the 1970s and 80s.
- burning 6x the land area
- lasting 5x longer.
despite climate change there is evidence that wildfires are not increasing everywhere?
1998-2015
between 1998-2015 globally burned areas declined by 24%, however this may be down to agricultural productivity and land use change, less that can be burned down
where do fires spread quickly?
on hills as heat rises
how can fires ‘jump’ across rivers and into areas?
lit debris
what are the three main types of wildfire burning? CSG
crown fires- burn entire tree top to bottom (most dangerous)
surface fires- leaf litter (easy to extinguish)
ground fires- burn at the dry peat or vegetation beneath the surface, move slowly through the dried underground (difficult to put out)
what are the two types of causes of wildfires?
natural- lightning, volcanoes, spontaneous
human- cigarettes, BBQ, agriculture, train line etc.
what are the political primary and secondary effects of wildfires?
P- gov buildings destroyed
S- borrowing money for international aid
what can prevent the ignition of wildfires?
public awareness
what is used in the US to warn people of wildfires?
Smoky bear, US mascot used to provide information on preventing wildfires,
how can people be prepared for wildfires? 3
- evacuation plans
- warning systems
- thermal infrared satellite imagery show people where wildfires are occurring therefore evacuation zones can set up
how can people mitigate wildfires ?
extinguishing or diverting the fire
what are long term mitigation strategies to reduce the impact of wildfires?
controlled burnings are burnings created on purpose to remove flammable materials so that less fuel is available, strictly monitored
what can people do that live in areas at high risk of wildfires to mitigate wildfires?
such as removing flammable materials from the area os that your house is less like to contribute to the fire
how can people adapt to wildfires?
insurance, globally reduce CO2 levels heightening the green house effect
what is the fatalistic outlook?
the view that we should let the wildfires burn and not stop them as wildfires eradicate disease and stimulate seed germination
give an example of when extinguishing the fire would have done more harm than good?
asper, Alberta. Threatening wildfires have been frequently extinguished in the past, meaning the forest has become thick and deprived of light. This has then prevented the growth of silver birch and other trees, and the forest is now mostly pine.
