GCSE 1.A - Challenge of Natural Hazards Flashcards
What is a natural hazard?
a natural process which could cause death, injury or disruption to humans, or destroy property or possessions
What is a natural disaster?
A natural hazard that has actually happened
What are the 2 main types of natural hazards?
- geological hazards
- Meteorological Hazards
What are geological hazards?
Hazards caused by land and tectonic processes
e.g. Volcanoes, earthquakes, landslides and avalanches
What are Meteorological Hazards?
Hazards cuased by weather and climate
e.g. tropical storms
What is the crust divided into?
Tectonic plates:
- Continental - Thicker and less dense
- Oceanic - thinner and more dense
Why are the tectonic plates moving?
Convection currents in the mantle
What is the place where the plates meet called?
Plate boundary/margin
What is a destructive margin?
2 Plates moving towards eachother
- Oceanic ( denser- Subducted) and continental creating gas-rich magma
- OR 2 Continental plates - fold mountains
What structures occur at destructive plate margins?
(Oceanic and Cont) - Volcanoes and ocean trenches
(2 cont) - Fold mountains
What is an example of a destructive plate boundary?
West coast of south africa - Oceanic Nazca plate subducted unter South American plate - Atacama Trench
What happens at constructive margins?
2 Plates moving **away ** from eachother
- Magma rises from the mantle to fill the gap and coolsm creating new crust
What happens at conservative Margins?
2 plates moving sideways or in the same direction but at different speeds
- Crust isnt created or destroyed
Which plate boundarys do volcanoes occur at? where else?
Destructive and constructive
- mantle hotspots
How do volcanoes form at destructive plate boundarys?
- The denser oceanic plate moves down into the mantle, where it melts.
- A pool of magma forms, which then rises through cracks in the crust called vents.
- The magma ( called lava when at surface) erupts, causing a volcano
How do volcanoes form at constructive plate boundarys?
the magma rises up into the gap created by plates moving apart, forming a volcano
What do volcanoes emit?
Lava and gases
Some emit lots of ash, which can cover land, block out the sun and form Pyroclastic flows
what is pyroclastic flow?
Super-heated currents of gas, ash and rock
How do earthquakes form at destructive plate boundarys?
Tension builds when one plate gets stuck as it moves past the other
How do earthquakes form at Constructive plate boundarys?
Tension builds along cracks in the plates as they move away from eachother
How do earthquakes form at Conservative plate boundarys?
Tension builds up when plates that are grinding past eachother get stuck
How do earthquakes form from tension in the plates?
The plates jerk past eachother, sending out shock waves
The waves spread out from the Focus
What is the focus?
The point in the earth where the earthquake starts - the waves are stronger nearer here and cause more damage
What is the epicentre?
the point on the earth’s surface straight above the focus
How are earthquakes mesured?
The moment magnitude scale
- the amount of energy released by and earthqauke
- Logarithmic scale ( x10 like pH)
What is the case study for Tectonic Hazards in contrasting countries?
New Zealand, Kaikoura 14 Nov 2016. magnitude: 7.8
Nepal, Gorkha 25th April 2015 Magnitude: 7.8
What is the GDP Per capita difference between New Zealand and Nepal?
NZ : US $40 331
NP: US $690
What is the Earthquake Primary effects difference between New Zealand and Nepal
- Deaths
NZ - 2 died and 50 injured
NP- 9000 people died and 22000 Injured - NP suffered 80x Building destruction but Nz damages cost 3.5 Billion more
- NP: Water tanks and Pipes destroyed 2 Million without access to clean wtaer and sanitation NZ: same
- NZ: 60 people provided with emergency hosuing NP: 4Million left homeless without support
What is the Earthquake Secondary effects difference between New Zealand and Nepal
- Nepal
- Lack of clean water caused Typhus outbreak, Killed around 13 people
- avalnches on mount eveerest killed 18 people - New Zealand
- Major road and railroad lines were blocked
- Tsunami caused with debri 250m inland
What is the Earthquake Immediate response New Zealand?
New Zealand:
- Tsunami warning issued quickly
- Emergency shelters provided
- 200 Most vunerable people evacuated from kaikoura by helicopter within 24 hours
- Power resoted within a few hours - temp water supplies set up
What is the Earthquake Immediate response Nepal?
- India and china sent teams to help reidents rescue people trapped by debris - lack of machineyr slowed down rescue efforts
- Previously damaged roads prevented emergency workers and aid to reach some of the injured
- Charities e.g. Oxfam provided medicine, food and temporary water supplies
- The red cross set up emergency shelters for 130000 families who had lost their homes
What is the Earthquake long-term response New Zealand?
$5.3million of funding was provided by the Kaikoura district council to help with rebuilding the town’s wtaer systems and harbour
- Most road and rail routes were repaired in 2 years
- The Kaikoura Mayoral Earthquake Releif fund was set up to help residents who couldnt afford basic supplies.
- March 2017, a permanent water main that was resilient to earthquakes was constructed
What is the Earthquake long-term response Nepal?
- Thw World Bank group Finanched $ 500 Million worth of projects to build earthquake-resistant housingm and repair roads and irrigation systems - projects are still ongoing
- Only the Roads from Nepal to Tibet was reopeed 2 years after, many roads are stil damaged
- Water supply is being restored, but many people still dont have acces to clean water
What are the positives of living near tectonic hazards?
- They’ve always lived there - family links
- In weathier countries, risk is minimised by preventions and planning
- Governmental support after earthquakes - 2001 Mount Etna, Italy support was provided
- Volcanic ash makes soil very fertile, attracting farmers - Mount Etna ideal for Grapes
- Tourism
What are the 4 main earthquake management strategies?
Monitoring
Prediction
Protection
Planning
How does monitoring reduce the effect of tectonic hazards?
- Earthquakes- Seismometers and larsers monitor earth movements to create early warning systems
- Volcanic Eruptions - Smaller earthquakes, escaping gas and shape of volcano can indicate early eruption
What is global atmospheric circulation?
the transfer of heat from the equator to the poles by the movement of air
- Divided into cells ( 3 per hemisphere) which each have a low pressure belt ( warm air rising) and a high pressure belt ( Cool sinking air)
Why does wind/ air movement occur?
Differences in air pressure - winds blow from high pressure areas to low pressure areas
How is the hadley cell created?
- The sun warms the Earth at the equator, causing the air to rise - Low pressure belt at the equator
- As the air rises it cools and moves awaya from the equator - 30 * north and south of the equator the cool air sinks creating a high pressure belt
What is the coriolis effect?
At ground surface on thre high pressure belts, the cool air moves either back to the equator ( As trade winds) or towards the poles ( as westerlies). The winds curve because of the earths rotation
How is the ferrel cell and polar cell created?
60 degrees noth and south of the equator the warmer surface winds meet colder air from the poles. The warmer air rises, creating low pressure. Some of this air then moves back towards the equator.
Some of this air moves towards the poles, cools and sinks creating high pressure, the high pressure is then pulled back towards to equator
What is the weather like at the equator due to atmospheric circulation?
the sun is directly overhead, creating solar radiation, making it hot
Warm, moist air rises and forms clouds , so it rains alot
What is the weather like at 30 degrees north and south of the equator due to atmospheric circulation?
Most of the air moisture has been released as rain. Dry air and little rain fall creates deserts
How does global atmospheric circulation affect UK weather?
It lies close to the low pressure zone at 60 degrees north. Warm air brings lots of cloud cover and rainfall, often as low pressure systems carried by the atlanti by westernly winds
When do tropical storm occur?
Between 5 and 30 degrees north and south of the equator when:
sea temp is 27 degrees c or higher
Wind shear ( Diff in wind speed) is low - Prevents clouds from beaking up as they rise so the storm stays in contact
How do tropical storms form?
- The warm surface evaportates, rises and condenses into clouds. This releases huge amounts of energy, producing powerful storms. The rising air creates of low pressure, which increases surface winds.
- Storms spin because of the coriolis effect
- As the storm moves over the ocean, the energy from the warm water strengthens the storm, so wind speeds increase
Why do tropical storms loose strength over land or cool water?
the energy supply from the warm water is cut
Why do tropical storms move towards the west?
easternly winds from near the equator
What are the properties of a tropical storm?
- circular, hundreds of Km wide and usually last 7-14 days. They spin anti-clockwise in the northern hemisphere and clockwise in the southern
Whats the centre of a tropical storm like?
Called the eye, it up to 50km across and its caused by descending air
Very low pressure, light winds, no clouds, no rain and a high temperature
Whats the eyewall of a tropical storm like?
Surrounding the eye, Theres spiralling rising air, very strong winds, storm clouds, torrential rain and a low temperature
Whats the edges of a tropical storm like?
The wind speed falls the clouds become smaller and more scattered, the rain becomes less intense and the temperature increases
What is the tropical storms case study and general facts?
Typhoon Haiyan
- Made landfall in the philippines on the 8th Nov 2013
What were the primary effects of Typhoon Haiyan?
- Over 6300 people were killed
- Over 1 Million homes were severely damaged or destroyed - 1.9 People were made homeless
- Strong winds damages electricity lines, water supplies were contaminated by salt water from storm surge
- Flooded 600, 000 hecatres of land
- Cost of damage US $13 Billion
What were the secondary effects of Typhoon Haiyan?
- Flooding triggered several landslides - Blokced roads and delayed arrival of aid
- 5.6 million workers lost their jobs after business and agricultural land were destroye
- lack of clean water caused outbreaks of diseases such as dysentery
What were the immediate responses to Typhoon Haiyan
PAGASA broadcast warnings about Typhoon Haiyan 2 days before landfall
- 800 000 People were evacuated but some died due to evacuation centres being flooded
- Philippines declared state of emergency which lead to many charities offering aid in form of food, shelter and clean water
- Plan International contrusted Pit Latrines for 100 000 people to help prevent the spread of disease
What were the long term responses to Typhoon Haiyan
- The UN appealed for 300 Million to help funding rebuilding and releif
- Charities built new storm resistant housing
- Philippines encouraged people to visit unnaffected sections of the country to aid through toursism
How may climate change affect tropical storms?
- Frequency - staying at 27C or higher for longer each year - more storms
- Distribution - Storms forming in new areas-
- Intensity - More evaporation - increased cloud formation
How can you plan against tropical storms?
- Prediction and Monitoring
- Planning
- Protection
Typhoon haiyan examples
**
Examples of the UK’s temperature becoming more extreme
- 10 warmest years all from after 2002, 2018 hottest summer on record.
- December 2010 was coldest month for over 100 years
Examples of the UK’s rainfall becoming more extreme
- Major flooding events occured and have become more frequent
- December 2015 was the wettest month ever recorded
What is the case study for UK weather hazards?
Somerset levels flooding in winter 2013-2014 - Experienced 3x average amount of rainfall
- Lots of rain fell on saturated ground and coincided with high tides and storm surges. This caused an extensive flooding of the Levels, an area of low-lying land criss-crossed by rivers
- The river had also not been dredges regularyl for 20 years, reducing its capacity
What were the social impacts of the Somerset levels flooding?
- More than 600 homes were flooded, and many people were forced to evacuate
- Villages e.g. Mulchelney were cut off by road
- Major transport links, e.g. A361 or train lines were closed
- Insurance prices soared, and many were unable to prevent their houses against future flooding
What were the environmental impacts of the Somerset levels flooding?
- 11500 were flooded, including famland - destroying many
- Standing made the ground toxic and unproductive for over a year - loss of nutrients and damage to soil structure decreased the long term fertility of the land
- Tonnes of mud and debris were left by the floods, damaging vegatation
What were the economical impacts of the Somerset levels flooding?
- the cost of damage to the somerset levels was estimated over £80 million
- local companies lost more than 1.2 million pounds in businesses
- Loss of tourism cost the county £200 million
What flood management strategies were in place before the somerset levels flooding?
- Warning systems gave people time to prepare e.g. the Met office warned people to find emergency accomodtion incase they had to leave their home
- Individuals and local authorities used sandbags and flood boards to try and limit flood damage to homes
What flood management strategies were in place after the somerset levels flooding?
the “Somerset levels and Moor flood action plan”
- 20 year plan aims to limit the risk of future flooding - £100 Million will be spent on:
- Creating additional pumping stations
- Regular dredging of rivers
- Building a tidal barrier at bridge water
- Widening rivers
How can prediction and monitoring reduce the effect of tropical storms?
- Monitored using radar, sattelites and aircraft. Computer model scan then be used to calculate a storms predicted path
- Time to evacuate
How can planning reduce the effect of tropical storms?
- Future developments can avoid high risk areas, such as low-lying coastal zones
- Governments can plan evacuation routes to ensure people can get away quickly
- Emergency services can prepare for disaster by practising rescuing people from flooded areas
How can protection reduce the effect of tropical storms?
- Infrastructure designed to withstand tropical storms
- Flood defences can be built along rivers
Interglacial period
In-between glacial periods
Glacial period
Very cold period of time
WHat are the 3 natural factors towards climate change?
Solar output
orbital changes
Volcanic activity
How do orbital changes
contribute towards climate change?
- Orbital changes affect how much solar radiation the earth receives - more energy = more warming
What are the 3 variations in the way the earth orbits the sun
Stretch - Circular/ elliptical - called eccentricity
Tilt - axis tilt (causes seasons)
Wobble - earth wobbles like a spinning top (precision)
these changes can cause the glacial and interglacial periods
How do volcanic activity
contribute towards climate change?
- major eruptions eject large quantities of material into the atmosphere
- Some of these particles reflect the suns rays back into space, so the earth cools
- Volcanic activity may cause short term cooling
- CO2 may be released
What is an example of volcanic activity causing short term cooling?
The earth cooled by about 0.5*C after Mount Pinatubo erupted in 1991
How does solar output
contribute towards climate change?
- The suns energy output changes in short cycles of about 11 years and long cycles of 100 years as well
- More solar output = Higher climate temp
This isn’t thought to have an outlying effect on climate change
What are the 4 ways that provide evidence for climate change?
Ice and sediment cores
Tree rings
Pollen analysis
Temperature analysis
How do ice and sediment cores provide evidence for climate change
Ice sheets are layers of ice - one forms each year
Scientists drill into ice sheets to get long cores of ice
By analysing the gases trapped in the layers of ice, you can tell what the temperature was each year
How do tree rings provide evidence for climate change
Tree rings grow each year and are thicker in warm, wet conditions
- Count rings for age of tree
- thickness of rings show climate
- Reliable for past 10, 000 years
How do pollen analysis provide evidence for climate change
Pollen from plants gets preserved in sediment
- This can be identified and dated to see what species were living at the time
- Compared to the plants now, we can see the conditions were similar so the climate is the same.
How do temperature records provide evidence for climate change
Since the 1850s, global temps have been measured using thermometers - gives a reliable but short term record
News paper and other historical records can be used to date further back
What are the 4 ways Humans contribute to greenhouse gases (climate change)
Burning fossil fuels
Farming
Cement production
Deforestation
Why does burning fossil fuels contribute to greenhouse gases (climate change)
CO2 is released into the atmosphere when fossil fuels like coal, oil, natural gas and petrol is burnt e.g cars or thermal power stations
Why does farming contribute to greenhouse gases (climate change)
1) livestock produces a lot of methane through farting or burping
2) Rice paddies contribute to global warming as flooded field release CO2
Why does cement production contribute to greenhouse gases (climate change)
Cement is made from limestone, which contains Carbon. When its produced it releases CO2
Why does deforestation contribute to greenhouse gases (climate change)
Plants remove CO2 and convert it into organic matter during photosynthesis.
- When they are cut down they stop dong this
- Burnt trees release CO2 to make way for agriculture
Why are tectonic plates moving?
convection currents
How is Climate Change affecting the environment?
Sea levels rising
Species declining - e.g. Great barrier reaf is suffering from bleaching
Precipitation patterns changing
Distribution and quantity of species / biodiversity
How is climate change causing sea levels to rise?
Warmer temperatures are causing glaciers to shrink and ice sheets to melt
-> Melting land ice (e.g. Greenland and antarctic ice sheets) means that water on land is returning to oceans, causing sea levels
How is sea levels rising affecting the environment?
Sea ice is shrinking, causing loss of polar habitats
Low-lying coastal areas (e.g. Miami and the USA), will flood more regularly. Coastal erosion will increase with sea level rise and some coastal areas will be submerged, so habitats will be lost
How is climate change affecting distrubution and quantity of species?
- Some species now live at higher altitudes due to warming temperatures
- Some habitats are being damaged or destroyed due to climate - species that are adapted to these environments may become extinct e.g. limited bamboo growth is causing decline in panda species
How is climate change affecting people
- Deaths due to heat increased - but deaths due to cold decreases
- Some areas have become so hot and dry they are inhabitable e.g. maldives - this leads to migration and often overcrowding
- Struggling water supply - political tensions on rivers crossing borders
-Farming - Money used on predicting extreme weather events, reducing their impacts and rebuilding each year
How is climate change affecting farming?
Decreasing yeilds of some crops, but also some crops are benefitting from warmer conditions
Lower crop yields can cause malnutrition and disease, particularly in lower latitudes
What are the 4 main climate change mitigation strategies?
- Planting trees
- Carbon Capture
- Alternative energy production
- International agreements
How does planting trees help mitigate climate change?
Increases the amount of CO2 that is absorbed from the atmosphere through photosynthesis
How does carbon capture help reduce Climate Change?
Carbon capture and storage (CCS) is designed to reduce emmisions from power stations burning fossil fuels
CCS involves capturing CO2 and transporting it to safe places where it can be stored, e.g. deep underground
How does alternative energy production help to mitigate climate change?
1) Replacing fossil fuels with nuclear or renewable energy can help reduce greenhouse gas emissions
2) in the UK, more offshore wind farms are being built
How do international agreements help mitigate climate change?
The Paris agreement aims to reduce greenhouse gas emissions and limit global warming. It came into force on the 4th November 2016 and has been signed by 195 parties, including the EU
Each country has set a pledge by how much they will reduce their greenhouse emmisions by. The UK has pledged to reduce their emissions by at least 68% from their 1990 levels by 2030
Mitigation strategies vs adaptation
Mitigation - reduce climate change
Adaptation - responding to the effects
What adaptation strategies are helping to respond to the effects of climate change?
Changing agricultural systems
Managing water supply
Coping with rising sea levels
How is changing agricultural systems helping to adapt to climate change?
Changing rainfall patterns and higher temperatures wil affect the productivity of existing systems
1) Plant new crop types that are more suited to the new cliate conditions of the area e.g. Soya, peaches and grapes in S England
2) Biotechnology used to create crops that are more resistant to extreme weather events e.g. drought resistant millets in Kenya
How is managing water supply helping to adapt to climate change?
Dry areas are predicted to get dryer, leading to more water shortages - so people need to use water supplys more effeciently
1) Water metres can be installed in homes to discourage excessive water usage
2) Rainwater and waste water can be collected and recycled
How is coping with rising sea levels helping to adapt to climate change?
1) Better flood warning systems and protection being built E.g. the thames barrier in london
2) In areas that cant afford expensive flood protection, people are building raised flood shelters and building on embankments e.g. Bangaladesh
