GEOGRAPHY UNIT 1A challenge of natural hazards Flashcards
What are not counted as natural hazards?
extreme events which do not pose any threat to human activity eg. a drought in an uninhabited part of a desert
What are the 2 types of natural hazard?
- geological hazards caused by land and tectonic processes
- meteorological hazards caused by weather and climate
What are the factors that affect natural hazard risk?
- vulnerability
- capacity to cope
- nature of natural hazards
How does vulnerability affect natural hazard risk?
the more people that are in an area exposed to natural hazards, the greater the probability they will be affected by the natural hazard
How does capacity to cope affect natural hazard risk?
- better a population can cope with an extreme event, the lower the risk of them being severely affected
- e.g. HICs are better able to cope with flooding as they can afford to build flood defences
How does nature of natural hazards affect natural hazard risk?
- type, risk from some hazards is greater than others e.g tropical storms can be predicted and monitored, volcanoes not
- frequency, natural hazards that occur more often are more likely to carry a higher risk
- magnitude, more severe natural hazards tend to have the greatest effects
What are the primary effects of natural disasters?
the immediate impacts caused by the hazard itself
What are some examples of primary effects?
- buildings and roads destroyed
- people injured or killed
- crops or water supplies contaminated or damaged
- electricity cables, gas pipes and communication networks can be damaged, cutting off supplies
What are the secondary effects of natural disasters?
happen later on as a result of the primary effects
What are some examples of secondary effects?
- initial hazard can trigger other hazards
- aid and emergency vehicles can’t get through because of blocked roads
- shortage of clean water can spread disease
- food shortages can occur if crops are damaged
- country’s economy can be weakened
What are some examples of immediate responses?
- evacuate people
- treat the injured and rescue
- recover dead bodies
- provide temporary electricity and gas
- provide food, drink and shelter
- foreign governments or charities may send supplies or aid
What are some examples of long-term responses?
- repair homes and rehouse people
- rebuild buildings or roads
- reconnect broken electricity, water and communication connections
- improve forecasting, monitoring and evacuation plans
- improve building regulations so that buildings can withstand similar hazards in the future
- boost economic recovery
What are tectonic plates?
earth’s crust is divided into slabs called tectonic plates that float on the mantle
Difference between oceanic and continental plates?
oceanic:
- thinner
- more dense
continental:
- thicker
- less dense
Why are tectonic plates moving?
convection currents
What happens when an oceanic plate meets a continental plate?
- denser oceanic plate is subducted and destroyed creating gas-rich magma
- volcanoes and ocean trenches are formed
What happens when 2 continental plates meet?
ground is folded upwards creating fold mountains
What happens at a constructive plate margin?
- two plates are moving away from each other
- magma rises to fill the gap and cools, creating new crust
What happens at a conservative plate margin?
- when two plates are moving in the same direction along each other at different speeds
- or when two plates are moving sideways past each other
- crust isn’t created or destroyed
How is a volcano formed at a destructive plate margin?
- denser oceanic plate moves down into mantle where it melts
- a pool of magma forms which rises through cracks in the crust called vents
- magma erupts forming volcano
How is a volcano formed at a constructive plate margin?
magma rises up into gap created by plates moving apart which forms volcano
How are some other volcanoes formed?
parts of the magma that are really hot called hotspots
What happens when a volcano erupts?
- emits lava and gases
- some emit lots of ash which can cover land, block out sun and form pyroclastic flows
What are pyroclastic flows?
super-heated currents of gas, ash and rock
How does an earthquake happen at a destructive margin?
- tension builds builds when one plate gets stuck as it moves past the other
- plates eventually jerk past each other sending out shock waves, these vibrations are the earthquake
How does an earthquake happen at a constructive margin?
- tension builds along cracks in the plates as they move away from one another
- plates eventually jerk past each other sending out shock waves, these vibrations are the earthquake
How does an earthquake happen at a conservative margin?
- tension builds up when plates that are grinding past each other get stuck
- plates eventually jerk past each other sending out shock waves, these vibrations are the earthquake
How are earthquake’s vibrations spread?
- shock waves spread out from focus, the point in the Earth where earthquake starts, these waves are stronger near focus and cause more damage
- epicentre is point on Earth’s surface above the focus
What is the moment magnitude scale a measure of?
the amount of energy that’s released by an earthquake
How do different magnitudes affect results of an earthquake?
- magnitude of 6 or below only cause slight damage to buildings, although can be worse in built up areas
- 7 or above can cause major damage and deaths
Where did the Chile earthquake take place?
off the coast of central Chile
What date was the Chile earthquake?
27th February 2010
What caused the Chile earthquake?
the oceanic Nazca plate subducted underneath the continental South American plate
What was the magnitude of the Chile earthquake?
8.8
What were some of the primary effects of the Chile earthquake?
- 500 died
- 12,000 injured
- loss of power, communications + water
- cost $30 billion
What were some the secondary effects of the Chile earthquake?
- tsunami which reached other countries, evacuation order reduced the loss of life
- fire at chemical plant, nobody killed
- roads blocked by landslides
What were some of the immediate responses to the Chile earthquake?
- temporary repair to route 5 N to S highway so emergency services could access those in need
- rescue work began immediately
What were some of the long-term responses to the Chile earthquake?
- strong economy could rebuild with little foreign aid
- power and water to 90% in 10 days
Where did the Nepal earthquake take place?
Gorkha, Nepal
What date was the Nepal earthquake?
25th April 2015
What caused the Nepal earthquake?
Indo-Australian plate subducted beneath the Eurasian plate
What was the magnitude of the Nepal earthquake?
7.8
What were some of the primary effects of the Nepal earthquake?
- 9000 died
- 22,000 injured
- water tanks and pipes destroyed, 2 million without access to clean water and sanitation
- cost $5 billion
What were some of the secondary effects of the Nepal earthquake?
- avalanches in Everest which killed 18 people
- lack of clean water caused outbreaks of typhus killed at least 13
- roads blocked by landslides
What were some of the immediate responses to the Nepal earthquake?
- people had to recover dead and treat injured but damaged roads made it harder for emergency workers and aid to get there
- India and China tried to help rescue those trapped by debris, lack of tools and machinery slowed down rescue efforts
What were some of the long-term responses to the Nepal earthquake?
- World Bank Group financed $500 million worth of projects to build new housing and repair roads and irrigation systems, some projects still ongoing
- -water supply still being restored but 2 years after many still didn’t have access to clean water
What is the GDP per capita of Chile?
over $27,000
What is the GDP per capita of Nepal?
$700
Why do some people not have a choice living in areas at risk of tectonic hazards?
- some people may not know the risks
- may not be able to afford to move
What are some reasons people choose to live in areas at risk of tectonic hazards?
- they’ve always lived there, moving means leaving jobs or families
- wealthier countries, effective monitoring and evacuation plans can minimise risks
- confident that their government will support them after an earthquake or volcanic eruption
- minerals from volcanic ash make volcanic soil very fertile
- volcanoes are tourist attractions so people live nearby to work in tourist industry
How are earthquakes monitored?
seismometers and lasers monitor earth movements, can be used in early warning systems to give a small warning before large earthquake occurs
How are volcanoes monitored?
scientists can measure tell-tale signs such as tiny earthquakes, escaping gas, or changes in the shape of the volcano
How can earthquakes be predicted?
cannot be reliably predicted but can forecast where they may occur by monitoring movement of tectonic plates
How can volcanic eruptions be predicted?
can be predicted if they are monitored closely
How can we be protected from earthquakes?
- new buildings can have reinforced concrete to absorb the earthquake’s energy
- existing buildings can be reinforced with steel frames can avoid collapse
- automatic shut-off switches can turn off gas and electricity supplies to prevent fires
How can we be protected from volcanoes?
- buildings can be strengthened so that they don’t collapse under the weight of ash
- trenches and barriers have been used to try and divert lava, not very successful
How can we plan for volcanoes and earthquakes?
- future developments should avoid high-risk areas
- emergency servers can prepare what to do
- people can be educated in the event of a hazard
- government can set up evacuation routes
- supplies such as food and water can be stockpiled in the event of a shortage
What is global atmospheric circulation?
the transfer of heat from the equator to the poles through the movement of air
Why does air move?
- differences in hair pressure
- winds blow from high pressure areas to low pressure areas
What are the names of the winds that move from 30˚ to the equator and 60˚?
- from 30 to 60, westerlies
- from 30 to 0, trade winds
How does global atmospheric circulation affect weather at the equator?
- the hottest point as the sun is directly overhead
- the warm air rises, cools and condenses to form clouds, so it rains a lot at equator
How does global atmospheric circulation affect weather at 30˚ north and south of equator?
- by the time the air reaches this altitude, it has released most of its moisture in the form of rainfall
- dry air means few clouds and little rainfall so deserts often found here
How does global atmospheric circulation affect weather in the UK?
- the UK lies close to low pressure system 60˚ north of the equator
- warm rising air brings lots of clouds and rainfall, often as low pressure systems carried from the Atlantic by westerly winds
How do tropical storms form?
- when they are between 5˚ and 30˚ north and south of the equator
- the sea temperature is 27˚c or higher
- low wind shear between higher and lower parts of atmosphere
How does a tropical storm form?
- warm surface water evaporates, rises and condenses into clouds
- this releases huge amounts of energy which forms powerful storm clouds
- rising air creates an area of low pressure which increases wind speed at surface
- low wind shear prevents clouds breaking up as they rise, keeping the storm intact
How does a tropical storm progress?
- easterly winds near the equator move the tropical storm towards the west
- storms spin because of the Coriolis effect
- as storm moves over ocean, the energy from warm water strengthens the storm and increases wind speed
How does a storm break up?
lose strength when they pass over land or cooler water because energy supply from warm water is cut off
What times of the year do tropical storms occur?
northern hemisphere: August-October
southern hemisphere: December-April
What are the key features of a tropical storm?
-circular in shape
-hundreds of kilometres wide
-last from 7-14 days
-northern hemisphere: anticlockwise
southern hemisphere: clockwise
What are features of the eye of a tropical storm?
- 50km wide
- caused by descending air
- low pressure
- light winds
- no clouds
- no rain
- high temperature
What are the features of the eyewall?
- surround the eye
- spiralling rising winds
- very strong winds, 160km/h
- storm clouds
- torrential rain
- low temperature
What are the features of the edges of a tropical storm?
- wind speed falls
- clouds become smaller and more scattered
- temperature increases
- rain becomes less intense
What date did Typhoon Haiyan make landfall?
8th November 2013
What were the worst affected areas of Typhoon Haiyan?
- Tacloban and Cebu
- 280mm of rain
- winds 314km/h
What storm surge resulted from Typhoon Haiyan?
- storm surge with waves 2.3m tall
- combined with a high tide, meant that Tacloban hit by 5m tall waves
What is a storm surge?
temporary rise in water level caused by wind pushing waves onshore
How many people were killed from Typhoon Haiyan? (primary effect)
8000
How did Typhoon Haiyan affect people’s homes? (primary effect)
- destroyed over 1 million homes
- over 1.9 million made homeless
How did Typhoon Haiyan affect electricity lines, water supplies and farmland? (primary effect)
- cut off electricity lines
- water supplies contaminated with salt water as a result of a storm surge
- heavy rain and storm surges destroyed 600,000 hectares of farmland
What was the cost of damage of Typhoon Haiyan? (primary effect)
$13 million
What were some secondary effects of Typhoon Haiyan?
- flooding triggered several landslides which blocked roads and delayed arrival of aid
- 5.6 million workers lost jobs after business and agricultural land was destroyed
- lack of clean water resulted in outbreaks of diseases such as dysentery
What did the Philippines’ meteorological society do? (immediate response)
- broadcast warnings about Typhoon Haiyan 2 days before it made landfall
- led to the evacuation of 800,000 residents
- unfortunately, some died when evacuation centres were flooded
What were some other immediate responses of Typhoon Haiyan?
- fishermen were warned not to go to sea
- Philippines declared a state of emergency which led to charities offering aid in the form of food, shelter and clean water
- Plan International constructed pit latrines for 100,000 people to prevent the spread of disease
What were some long-term responses of Typhoon Haiyan?
- UN appealed for over $300 million to help rebuilding and fund relief
- charities built new storm-resistant houses for those who lost their homes
- Philippines’ tourism board encouraged tourism saying that most areas unaffected and tourism would help with rebuilding process
How have global sea temperatures risen?
- risen by 0.9˚c since 1880 and expected to rise more because of climate change
- may affect tropical storms’ intensity, frequency and distribution
How could climate change affect frequency of tropical storms?
- oceans will stay at 27˚c or higher for longer each year
- this means that there’s a longer period where storms can form
- this means that there could be a greater number of tropical storms
How could climate change affect the distribution of tropical storms?
- as the average sea temperature rises, more of the world’s oceans could be at 27˚c or higher
- this means that tropical storms could take place in areas that have never experienced them
How could climate change affect the intensity of tropical storms?
- higher sea temperatures could result in more evaporation and increased cloud formation
- this increases the energy released which increases the power of tropical storms
How can prediction and monitoring be used to reduce the effect of tropical storms?
- storms can be monitored using radar, satellites and aircraft
- computer models can then be used to calculate the predicted path of the storm
- predicting where and when a storm will take place gives people time to evacuate and protect homes or businesses
How can planning be used to reduce the effect of tropical storms?
- future developments can avoid high risk areas
- governments can plan evacuation routes in advance
- emergency services can practise, e.g. practise rescuing someone in flooded building
How can protection be used to reduce the effect of tropical storms?
- buildings can be designed to withstand tropical storms
- buildings can be built on stilts so they’re safe from floodwater
- flood defences can be built along rivers and coasts
What are 6 weather hazards that the UK experiences?
- strong winds
- heavy rainfall
- snow and ice
- drought
- thunderstorms
- heat waves
What are some impacts of strong winds in UK?
- strong winds can damage properties and disrupt transport
- uprooted trees and debris can kill or injure people
What are some impacts of heavy rainfall in UK?
- too much rain can result in flooding which can damage homes, disrupt transport networks and kill people
- recovery from flooding can cost millions of £
What are some impacts of snow and ice in UK?
- snow and ice cause injuries due to slipping on ice and deaths due to cold
- schools and businesses can be forced to shut, closing of transport networks can have economic impact
What are some impacts of drought (lack or precipitation) in UK?
- water supplies can run low which can cause economic impacts such as damaged crops
- rules to conserve water (such as hosepipe bans) may have to be introduced
What are some impacts of thunderstorms in UK?
- heavy rain, strong winds and lightning can all occur during a thunderstorm
- lightning can cause fires which can damage properties and the environment and could also kill people
What are some impacts of heat waves in UK?
- during long periods of hot weather, pollution builds up in the air
- this can cause heat exhaustion or breathing difficulties which can kill people
- disruption to transport such as rails buckling or roads melting can have economic impacts
- however, hot weather could benefit tourist industry
How is temperature in the UK becoming more severe?
- UK’s ten warmest years on record all occurred since 1990
- December 2010 was coldest month for over 100 years
How is rainfall in the UK becoming more severe?
- more rainfall records broken between 2010 and 2014 than any decade on record
- December 2015 was wettest month ever recorded
When did the Beast from the East occur?
started on 24th February 2018
What was the Beast from the East?
it was a cold wave which brought widespread unusually low temperatures and heavy snowfall across the Great Britain and Ireland
What caused the Beast from the East?
- caused by a change to the northern polar jet stream which twisted direction unexpectedly bringing in cold weather from the east
- bend caused by a jump in temperatures in the Arctic known as a sudden stratospheric warming
What were some social impacts of the Beast from the East?
- gridlocked roads, no trains and no buses meant that many workers were stuck at home
- 17 people died
- drifting snow meant many villages were isolated
What were some economic impacts of the Beast from the East?
- economy was losing £1 billion every day
- affected the construction sector, nearly losing £2 billion over the course of 3 days
- general economic output fell by 20%
What were some environmental impacts of the Beast from the East?
- heavy snow damaged farmland which destroyed crops
- many people using heating which resulted in National Grid issuing a ‘gas deficit warning’, fears of gas shortage
- many coastlines issued with flood warnings
What were some management strategies for the Beast from the East?
- stranded drivers were given foil blankets
- Army and RAF personnel called to ferry health workers through blocked roads in Lincolnshire and Scotland
- Cleveland Mountain Rescue took nurses to elderly people living in rural areas in East Cleveland and North Yorkshire Moors
What is climate change?
any significant change in the Earth’s climate over a long period of time
When is the Quaternary period?
from 2.6 million years ago to present day
What was climate like before Quaternary period?
warmer and quite stable
How has the Earth’s climate changed during the Quaternary period?
climate has shifted from cold glacial periods that last 100,000 years to warm interglacial periods that last 10,000 years
When did the last glacial period end?
- 15,000 years ago
- since then the climate has been warming
What is global warming?
- the term used to describe the sharp rise in global temperatures over the past century
- it’s a type of climate change
How can ice be analysed to find out about the climate?
- ice sheets are made up layers of ice, one layers is formed each year
- scientists drill into ice to get long cores of ice
- by analysing the different gases trapped in each layer, scientists can know what the temperature was each year
How can sediment be analysed to find out about the climate?
- remains of organisms taken from ocean sediments can also be analysed
- these can be used to find about temperatures from 5 million years ago
How can temperature records be analysed to find out about the climate?
- since 1850s, global temperature has been measured using thermometers, this gives us accurate but short record of climate
- using historical records like harvest records or newspaper weather records allows us to find out further back
How can pollen analysis be used to find out about the climate?
- pollen from plants gets preserved in sediment, e.g. at bottom of lakes or in peat bogs
- scientists can date and identify types of pollen to find out species
- scientists know condition that plants live in now, so similar plants must have lived in similar climate
How can tree rings be analysed to find out about the climate?
- as a tree grows, it forms a new layer, these layers are thicker in warm and wet conditions
- by counting the number of rings in a core, scientists can determine age and thickness of ring can determine climate
- trees are a useful way of learning about the climate from up to 10,000 years ago
How do orbital changes cause climate change?
- orbital changes affect how much solar radiation the earth receives, more radiation received means more warming
- orbital changes include:
- stretch; the earth’s orbit around the sun can vary from a circular one to an elliptical one, also called eccentricity
- tilt; the earth’s axis is tilted at an angle as it orbits
- wobble;
- wobble; earth’s axis wobbles like a spinning top. also called precession
- these changes may have caused the glacial and interglacial periods of the Quaternary period
How does volcanic activity affect climate change?
- major volcanic eruptions eject large quantities of material into the atmosphere
- some of this material reflects the sun’s rays back out to space so the earth cools
How does solar output affect climate change?
- sun’s energy output isn’t constant, changes in cycles lasting 11 years and possible cycles lasting hundreds of years
- reduced energy output means that the earth’s climate may be cooler in some areas
- not thought to have a great impact on climate change
What are 4 human factors that affect climate change?
- burning fossil fuels
- cement production
- farming
- deforestation
How does cement production affect climate change?
- cement is made from limestone which contains lots of carbon
- when cement is produced, lots of CO2 is released into the atmosphere
How does farming affect climate change?
- farming livestock releases a lot of methane
- rice paddies contribute because flooding fields releases methane
How does deforestation affect climate change?
- plants remove CO2 through the process of photosynthesis
- when trees are cut down, they stop taking in CO2
- CO2 is also released when trees are burnt as fuel or to make way for more agriculture
How are temperatures expected to rise in the future?
by 0.3˚c between 2005 and 2100
How will climate change affect ice?
- warmer temperatures mean that glaciers and ice sheets melt, this means that water stored in land is returning to sea, causing levels to rise
- sea ice is shrinking, leading to a loss of polar habitats
- rising sea levels means that low-lying coastal areas will flood more regularly
- coastal erosion will increase and some coastal habitats may be submerged leading to loss of habitats
How does climate change affect species?
- e.g. coral reefs exposed to bleaching causing them to starve and die
- some species live at higher latitudes due to higher temperatures
- some habitats are being damaged or destroyed, the animals that are adapted to these habitats may become extinct
How does climate change affect precipitation?
- precipitation patterns are changing
- global warming affecting how much rain some areas may get
How does climate change affect human deaths?
- deaths due to heat have increased
- but deaths due to cold have decreased
How does climate change affect weather?
- weather is going to be more extreme
- this means more money has to be spent on predicting weather, reducing its impacts and rebuilding after the event has occurred
How does climate change affect human habitats?
- some areas could become so hot and dry that they become uninhabitable
- some low-lying coastal areas could become submerged or flood so frequently that people may be forced to move
- this may lead to migration and overcrowding in other areas
How does climate change affect farming?
- globally, some crops have suffered due to increase int temps e.g. Argentina has had shorter wheat yields
- however, some countries in high latitudes find that their crops benefit from the warmer weather as they produce a greater yield
- lower crop yields could increase malnutrition, illness and death
How does climate change affect water supply?
- some countries struggling to supply enough water due to reduced water availability caused by rainfall patterns
- this could cause political tensions e.g. where rivers cross borders
What do mitigation strategies do?
reduce the causes of climate change
What are 4 mitigation strategies to reduce the causes of climate change?
- carbon capture
- planting trees
- alternative energy production
- international agreements
How does carbon capture reduce the causes of climate change?
- Carbon Capture and Storage is designed to reduce emissions from power stations
- CCS involves capturing CO2 and transporting it to somewhere e.g. deep underground
How does alternate energy production reduce the causes of climate change?
- replacing fossil fuels with nuclear or renewable energy can help reduce greenhouse gas emissions
- UK, building offshore wind farms
How do international agreements reduce the causes of climate change?
- Paris Agreement aims to reduce greenhouse gas emissions and limit global warming
- signed by 195 parties on 4th November 2016
- encourages developed countries to put mitigation strategies in place for developing countries
What is the Paris Agreement?
- each country has signed a pledge which says how much they aim to reduce their greenhouse gas emissions by
- EU and UK have agreed to reduce their emission levels by 40% since 1990
What are three adaption strategies to respond to the effects of climate change?
- changing agricultural systems
- managing water supply
- coping with rising sea levels
How does changing agricultural systems respond to the effects of climate change?
- changing rainfall patterns and higher temperatures may affect current productivity
- may be more suitable to plant new types of crops that are more suited to be grown in the new climate conditions of an area
- some regions, biotechnology is being used to create new types of crops that are resistant to extreme weather events
How does managing water supply respond to the effects of climate change?
- dry areas are expected to get dried, so people need to use water more efficiently
- water meters can be installed in houses to discourage excess water usage
- rainwater and waste water can be collected and recycled
How does coping with rising sea levels respond to the effects of climate change?
- at current levels, sea is expected to rise 65cm by 2100 this would flood many coastal areas
- better flood warnings are being put in place and more physical flood defences are being built
- in developing countries, houses can be built on embankments and build raised flood shelters
