Hazards Flashcards
What is a hazard
A potential to threat human life and property
What are the 3 major types of hazard
Geophysical - caused by land processes eg volcanoes - majorly tectonics
Atomospheric - eg wildfires caused by weather
Hydrological - caused by water bodies and movement eg flooding
What is perception
People have different viewpoints of how dangerous a hazard will be what risk they pose
Dependent on lifestyle, economic, cultural factors
What is prediction
Using past events in order to know when a hazard will take place
What is adaptation
Attempting to live with hazards by adjusting lifestyle choice
Mitigation
Strategies carried out to lessen severity of hazard
Management
Strategies to reduce hazards effects
What is the Park model and what is the 4 bottom axis
Graphical representation of steps carried out in hazard recovery
-can be used in comparing hazardous events (eg hazardous event in LIC will have longer recovery time than HIC)
steepness of curve shows how quickly an area deteriorates and recovers
depth of the curve shows the scale of the disaster (ie. lower the curve, lower the quality of life)
pre- disaster
Relief
Rehabilitation
Reconstruction
What is stage 1 - Relief (Parks model)
(hours-days)
- immediate local response - medical aid, search and rescue
- immediate appeal for foreign aid- the beginning of the global response
What is stage 2- rehabilitation (parks model)
(days-
Hazards caused by volcanoes
Lava flows
Lahars(mudflows) - caused by melting ice at high latitudes
Floods- melting ice
Tephra - why rock ejected from volcano
Toxic gassed - released during eruptions
Acid rain - cause by sulfur dioxide released into atmosphere
Pyrocoastic flows - clouds of burning hot ash and gas that collapse down volcano at high speeds
Tsunami
Cause when water is displaced from plates moving underwater, creating a large wave
Liquifactuon
When soul is saturated , vibrations of earth cause it to act like liquid . Soil becomes weak
Storm surge
Large rises in sea level - low pressure and Hugh winds
What is a natural hazard
caused by natural processes
What is vulnerability
how susceptible a population is to the damage caused by a hazard
Impacts of hazards
Hazards can have significant impact while they are occurring and often need an emergcancy response
impacts can also go on for a long tie after the hazard has passed
How do circumstances of people affect their perception of hazards
people view hazards in different ways:
some will believe that they will never experience a hazard
some adapt their lifestyle to minimise risk
and some accept hazards as being beyond their control
There are many responses to hazards that individuals and the gov. may take to try reduce vulnerability and its impacts
people may try to prevent a hazard for example;
building flood defences.
people may try to mitigate impacts by protection and adaptation
gov may coordinate response to a hazard to manage effectively
How can level of development affect how well a country manage hazards affectively
lack of wealth and technology
can lead to lack of education of hazards and how to stay safe and may not get warnings on phones etc
How is the park model good
shows how responses progress during a disaster which may help learners predict what resources will be needed for each stage,
also helps planners prepare for future hazard
What are the four phases in the hazard management cycle (state)
mitigation
preparedness
response
recovery
What are the four phases in the hazard management cycle (describe)
Mitigation- aims to minimise impact of future disasters
preparedness- about planning how to respond to hazard
response- how people react when a disasters occurs
recovery- about getting the affected area back to normal
The inner and outer core contain lots of ….?
iron and nicklel
The inner core is a
solid ball
the outer core is
semi- molten
iron/nickel
What type of crust is thicker continential or oceanic?
continental is thicker at 30-70km but is less dense than
oceanic crust which is thinner (6-10km) but more dense
What is the earths main internal source of energy
some of the heat energy is leftover from when the earth formed and some is left over from radioactive decay of elements such as uranium
What are the theories of how tectonic plates move
convection currents
ridge push
slab pull
How do convection currents move tectonic plates?
The core is very hot and lower parts of the asthenosphere heat up and slowly rise
as they move towards the top of asthenosphere they cool down, become dense and slowly sink
the circular movements of the semi molten rock create drag on base of tectonic plate causing them to move
How does slab pull move tectonic plates
at destructive plate margins
denser crust is forced under less dense crust
How does ridge push move tectonic plates
at constructive plate margin- magma rises to surface and formms a new crust.
This heats the surrounding rocks which expand and rise above the surface of the surrounding rocks forming a slope
as the new crust cools and becomes denser- gravity causes the denser rock to move down slope away from plate margins
this puts pressure on plate margins- causing them to move apart
What is seafloor spreading
as tectonic plates diverge, magma rises up to fill in the gap created- this then cools to form new crust
over time the new crust is dragged apart to form more new crust
whe this happens at a plate margin under the sea the plate margin gets wider
what does seafloor spreading create
mid ocean ridges
3 types of plate margins
constructive, destructive and conservative
what type of plate margins do volcanoes occur?
constructive and destructuve
Economic factors that influence perceptions of hazards
-quality of housing and infrastructure is likely to be higher in wealthier areas- this may mean that people feel safer
- increased spending and preparation and prediction- this may mean that people are more aware of the risks and are able to evacuate
-more investment in education- this may mean that people understand the potential dangers and are more likely to take action to minimise risk
Cultural factors that influence perception os hazards
-cultural values and beliefs may affect whether people trust scientific and government officials- this may mean they underestimate the risk
-some cultures believe that hazards are an act of god- may mean they dont wan to evacuate
people who have previously experienced a hazard may be more fearful- may mean they are more prepared
What type of landforms are formed at destructive - continental/ continental plates
What type of landform are formed at destructive plate boundaries - oceanic/oceanic
What landforms are formed at destructive plate boundaries- continental / oceanic
What type of landforms are formed at conservative plate boundaries
What type of landforms are formed at constructive plate boundaries - oceanic / oceanic
What type of landforms are formed at constructive plate boundaries- continental/ continental
What is the incidence
Frequency of a hazard
What is intensity
the power of a hazard - ie how strong it is
what is magnitude of a hazard
the size of the hazard, usually this is how a hazard’s intensity is measured
What is the distribution of a hazard
where hazards occur
What is level of development
economic development will affect how a place can respond to a hazard,
so a hazard of the same magnitude may have very different effects in two places of contrasting levels of development
What is perception
people different viewpoints of how dangerous hazards are and what risk they pose.
What ar preceptions dependent on
lifestyle factors- such as economic nd cultural facors
eg a wealthy person- less likley to view hazard as dangerous as they have money to respond to it
What is fatalism
the viewpoint that hazards are uncontrollable natural events, and any losses should be accapted as there is nothing that can be done to stop them
What is risk sharing
a form of community preparedness, whereby the community shres the risk posed by a natural hazard and invests collectively to mitigate the impacts of future hazards
Continental and oceanic- destructive
-denser oceanic plate subducts below continental
- the plate subducting leaves a deep ocean trench
- built up pressure from the melting plate cause explosive volcanoes bursting through the continental plate
Oceanic and oceanic- destructive
- Heavier plate subducts leaving an ocean trench
-built up pressure causes underwater volcanoes bursting throuht the oceanic plate
-lava cools and creates new land called island arcs
Continental and continental - destructive plate boundary
-both plates are not as dense as oceanic so lots of pressure builds
-ancient oceanic crust is subducted slighlty, but there is no subduction of continental crust
- pile up of continental crust on top of lithosphere due to pressure between plates
- Fold mountains formed fom piles of continenal crust
Oceanic and oceanic- constructive plate boundary
-magma rises inbetween the gap left by the two plates seperating, forming new land when it cools
-less explosive underwater volcanoes formed as magma rises
-new land roming on the ocean floor by lava filling the gaps is known as sea floor spreading
Continental to continental- constructive plate boundary
-any land in the middle of the seperation is forced apart, causing a rift valley
-volcanoes form where the magma rises
-eventually the gap will most likely fill with water and seperate from the main island
Forces influencing how convergent boundaries occur- RIDGE PUSH
Ridge push- the slope created when plates move apart has gravity acting upon it as it has a higher elevation
Forces infuencing how convergent boundaries occur- Slab pull
When a plate subducts, the plate sinking into the mantle pulls the rest of the plate (slab0 with it, causing further subduction
What happens at a conervitave plate boundary
parralel plates move in different directions or at different speeds
no plates are destroyed so no landforms are created
What are hotspots
Areas of volcanic activity that are not related to plate boundaries
Hot magma plumes from the manta rise and burn through weaker parts of the crust.
This can create volcanoes and islands
The pume stays in the same place but the plate continue to move, which sometimes causes a chain of islands (such as Hawaii)
Spatial distribution of volcanic hazards
Along constructive or destructive plate boundaries or located on hotspots
How to measure the maginitude of a volcano
Vulcanicity is measured using the Volcanic Explosivity Index.
The more powerful- the more explosive
Frequency of volcanic hazards
Volcanoes are classed as either active, dormant or extinct.
Estimated 50-60 volcanoes erupt each month
Regularity of volcanic activty
Eruptions are regular in that the eruption on each type of boundary are similar
(eg eruptions on destructive boundaries will regularly be more explosive than at constructuve boundaries)
however some can be irregular and not fit patterns
Predictabilty of volcanic eruptions
Regularity of eruptions can help estimate when eruptions willl take place
Seismic activty, gases releasing can all indicate an imminent eruption
NO DEFINITE way to predict volcanic eruption
What types of hazards are causes by volcanoes
Lava flows
Lahars
Floods
Tephra
Toxic gasses
acid rain
Nuees aredentes/ pyroclastic flow
What are lahars and reason for them
(mudflows)
usually caused by melting ice at high latitudes
What is tephra
any type of rock that is ejected by a volcano
What are Nuees ardentes/ pyroclastic flows
clouds of burning hot ash and gas that collapses down a volcano at high speeds
Primary and secondary effects of volcanic hazard-
Environmental
-PRIMARY
ecosystems damaged through various volcanic hazards
-wildlife killed
SECONDARY
-water acidified by acid rain
-gases contribute to greenhouse effect (global warming
Primary effects and secondary of volcanic hazard-
Economic
PRIMARY-
Businesses and industries destroyed or disrupted
SECONDARY-
Jobs lost
-profit form tourism lost
Primary
and secondary effects of volcanic hazard-
Social
PRIMARY
-people killed
-homes destroyed
SECONDARY
-fires can start
-trauma
homelessness
respiratory diseases
Primary
and secondary effects of volcanic hazard-
Poltical
PRIMARY
-government buildings disrupted or damaged
SECONDARY
-conflicts concerning govt. response eg food shortages insurance etc
Management to volcanic hazards
PREVENTION
AND
PREPARDENESS
Prevention- cant be prevented, only the risk to people can be prevented (eg not building near volcanoes)
Preparedness- monitoring increases notice of eruptions- warnings can be given out,
education on what to do- protects people
evacuation procesdures
training response teams
Management to volcanic hazards
MITIGATION
AND
ADAPTATION
Mitigation
-direct intervention eg concreate blocksto steer lava away from areas at risk
-strenghten buildings
-evacuation zones
-mitigating health effects by having emergancy services, aid and rescue
ADAPTATION
-capitalise on opportunities such as tourism
Spatial distribution of seismic hazards
along ALL BOUNDARIES
Magnitude of seismic hazards
Seismicity is measured using the RICHTER SCALE- measure of the strength of seismic waves
Mercalli scale also used- measures rate of destruction caused
Frequency of seimsic hazards
earthquakes are frequent around the world and occur every day
Hundreds of smaller magnitude earthquakes that cannot be felt by humans occur everyday
- but larger ones are less frequent
Regularity of seismic hazards
earthquakes follow no pattern and are random so there is irregularity between events
Predictability of seismic hazards
almost impossible to predict
Microquakes may give some indication but the magnitude cannot be predicted as how strong they are is random
Hazards caused by seismic events
Shockwaves
Tsunamis
Liquefaction
What are shockwaves
(seismic waves) - energy released from the sudden jolt that vibrates through the ground
What are Tsunamis
Caused when water is displaced from plates moving underwater, creating a large wave
What is liqefaction
when soil is saturated, the vibrations of an earthquake cause it to act like a liquid.
soil becomes weaker and more likely to subside when it has a large weight on it
Avalanches and landslides
Primary & secondary effects of seismic hazards- environmental
PRIMARY
-earthquakes can cause fault lines which destory the equiptment
-liquefaction
SECONDARY
-radioactive materials and other dangerous substances leaked from power plants
-saltwater from tsumanis flood fresh water ecosystems
-soil salinosation
Primary & secondary effects of seismic hazards- economic
Primary
- businesses destroyed
Secondary
-economic decline as businesses are destroyed
-high cost of rebuilding and insurance payout
-sources of income lost
Primary & secondary effects of seismic hazards- social
primary-
-buildings collapse
-injury/dealth
secondary
-gas pipes rupture- starting fires which can kill
-water supplies contaminated- spreading disease
Tsunamis- lead to damaging floods
Primary & secondary effects of seismic hazards- political
PRIMARY
-government buildings destroyed
SECONDARY-
-political unrest from food or water shortages
-can be initial chaos and lawelessness (eg looting)
RESPONSE AND RISK MANAGEMENT TO SEISMIC HAZARDS- prevention
majority of seismic hazards cannpt be prevented- eg earthquakes and tsunamis
liquefaction of soils can be prevented through soil stabilisation
RESPONSE AND RISK MANAGEMENT TO SEISMIC HAZARDS- preparedness
earthquake prone areas such as japan have extensive awareness strategies and education im place - eg in schools Drop, cover, hold on.
earthquake and tsunami warnings systems
evacuation plans and training
RESPONSE AND RISK MANAGEMENT TO SEISMIC HAZARDS- mitigation
search and rescue, immediate emergency aid, evacuation (short term)
demolishing older, unsafe buildings
Tsunami wave breaks and sea walls
RESPONSE AND RISK MANAGEMENT TO SEISMIC HAZARDS- Adaptation
-Move away from at risk areas
-capitalise on opportunites, such as tourism
-insurance if living areas of risk
-changing lifestyle choices- eg moving valuabel items so they dont fall
-building speically desinged earthquake proof buildings
What is a tropical storm
a low pressure, spinning storm with high winds and torrential rain
Condtions for a storm to form
Temperature- ocean temp 26-27*C
rotation: forms around equator but no less then 5 dgerees on either side
air pressure- must be in areas of unstable air pressure- usually where areas of high pressure and low pressure meet (convergence) - so that warm air rises more steadilu and the clouds form
Spatial distribution of tropical cyclones
Magnitude of tropical cyclones
Measurede on the Sffir-simpson scale (1-5) based on windspeed and thus the power of the storm
Frequency of tropical storms
Northern-hemisphere from JUNE-NOVEMBER
Southern hemisphere- november to april
Regularity of tropical storms
are irregular because although they occur in same areas, their path does not follow a set routinen- route taken is dependant on the storm and climatic conditions
Predictability of tropical storms
form far away from land meaning satelite tracking of cloud formations and movement can occur and general route can be predicted
Hazards caused by tropical storms
high winds- over 300km/h
flooding- due to heavy rain and storm surges
landslides- soil heavy
storm surges- large rise in sea levels
Primary and secondary effect of tropical storms- environmental
PRIMARY
-beaches eroded
-coastal habitats such as coral reefs destroyed
Secondary
-river flooding- salt water contamination
-animals displaced
Primary and secondary effect of tropical storms- economic
PRIMARY
-businesses destroyed
-agricultural land damaged
Secondary
-high cost of rebuilding and insurance payout
-sources of income lost
-economic decline
Primary and secondary effect of tropical storms- social
Primary
- drowning
- -debris
- injury
- buildings destroyed
Secondary
-homelessness
poluted water supply- spread disease
-foodshortages- damaged by land
Primary and secondary effect of tropical storms- political
primary
-govt. buildings destroyed
secondary
- issues paying back international aid
- pressure for govt to do more about global warming
RESPONSE AND RISK TO MANAGEMENT TO TROPICAL STORM- prevention
cannot be avoided- however trying to mitigate climate change could prevent higher category storms
RESPONSE AND RISK TO MANAGEMENT TO TROPICAL STORM- preparedness
awareness through education
evacuation plans
satelite image tracking
storm warning and tv broadcasts
RESPONSE AND RISK TO MANAGEMENT TO TROPICAL STORM- mitigation
search and rescue, immediate emergancy aid etc
strengthing homes
clearing loose debris before storms
RESPONSE AND RISK TO MANAGEMENT TO TROPICAL STORM- adaptation
move away from area at risk
deisgn buildings to withstand high winds and flood damage
flood defenses such as houses on stilts, coastal walls etc
