Paper 1 case studies and important info (excluding formations/defences of coasts and rivers) Flashcards
Tectonic Hazards:
constructive plate margins
At constructive plate margins, two plates are moving apart from eachother due to the opposite movements of convection currents in the mantle underneath. As they move apart, fissures are created through which magma forces its way to the surface, forming new land or shield volcanoes, as the magma is very hot and fluid. Earthquakes can also happen as a result of the magma breaking through the overlying crust
Tectonic hazards:
Destructive plate margins
At destructive plate margins, an oceanic and continental plate are moving toward eachother. Since the oceanic plate is denser, it is subducted under the continental crust. This happens at the subduction zone which creates deep ocean trenches as it pulls down part of the continental plate. As the oceanic plate enters the mantle, it begins to melt which creates more magma which breaks thorugh the crust forming steep sided composite volcanoes due to the viscous lava. This process also creates immense pressure and friction and earthquakes are caused by a release of seismic energy when the plates slip past each other.
Tectonic hazards:
collision plate margins
At collision plate margins, plates of similar densities are forced towards eachother because of the mantle’s convection currents. Due to their similar densities, neither plate is subducted under the other, and so they instead collide and fold upwards, creating fold mountains
Tectonic Hazards:
Conservative plate margins
At conservative plate margins, two plates of similar densities slide past eachother in opposite directions and at different speeds. This grinding between the two plates creates friction and builds stress energy, which is eventually released in the form of an earthquake, a release of the stress/seismic energy.
Tectonic Hazards:
Chile Nepal earthquakes
Nepal Effects:
Date - April 2015
Magnitude - 7.8
Primary effects:
9,000 deaths
20,000 injured
3 million homeless
$5 billion in damages
Secondary effects:
landslides and avalanches caused widespread damage to infrastructure.
19 people were killed in avalanches on mount everest.
Tectonic Hazards:
Chile Nepal earthquake
Nepal responses:
Immediate responses:
The government distributed 5,000 shelters and fundraised for an additional 30,000.
Emergency services and search and rescue teams were deployed quickly.
$60 million was raised in relief funds after a national appeal
Long term responses:
The government set up a national housing reconstruction plan after one month, pledging $2.5 billion in housing subsidies for 196,000 households.
Thousands of houses were deemed unsafe and were demolished.
Tectonic Hazards:
Chile Nepal earthquake
Chile Effects:
date - february 2010
Magnitude - 8.8
Primary effects:
500 deaths
12,000 injured
800,000 people affected
$30 billion in damages
Secondary effects:
Landslides damaged 1500 km of roads, whcih cut off rural communities and slowed relief efforts.
tsunami devastated coastal towns and destroyed ports
Tectonic Hazards:
Chile Nepal Earthquake
Chile responses:
Immediate responses:
International aid arrived from the UK, India and china with medical support and search and rescue teams.
500,000 tents were provided, largely from unicef.
Over $87 million was raised in aid by donations
Long term responses:
In 2019, 75% of homes that were destroyed were either fully rebuilt or under repair
In june 2015,, Nepal hosted an international conference to seek advice and financial support.
Weather Hazards:
Formation and structure of a tropical storm
1) a stong upward movement of air draws water vapour up from the warm ocean surface
2) the evaporated air cools as it rises and condenses to form thunderstorm clouds
3) As the air condenses, it releases heat which powers the storm and draws up more water from the ocean
4) rising air creates low pressure, Air rushes in to fill the gap left by rising air
5) the rotation of the earth means winds don’t blow straight. They circle towards the centre.
6) as the storm is carried across the ocean by the prevailing winds it continues to gather strength.
Weather hazards:
typhoon haiyan
Typhoon Haiyan effects:
date - november 2013
category - 5
primary effects:
approx 6300 people died most through drowning by the storm surge.
30,000 fishing boats destroyed by the surge
Tacloban airport and port badly damaged
Secondary effects:
14 million people affected, many left homeless and 6 million lost their income.
looting and violence broke out in tacloban city.
Flooding and landslides blocked roads, cutting off aid to many remote places.
shortages of water and food led to outbreaks of disease.
Weather Hazards
Typhoon Haiyan
Typhoon Haiyan responses:
immediate responses:
International aid agencies responded with food, water and temporary shelters.
Over 1200 evacuation centres set up for the homeless. Uk sent shelter kits to provide emergency shelter for a family.
Long term responses:
The UN donated financial aid, supplies and medical support
‘cash for work’ schemes where locals were paid money to clear debris
oxfam helped finance replacement of fishing boats
Weather Hazards (in the UK)
An example of a recent extreme weather event in the uk - Somerset level Floods
Impacts of the floods were:
Social:
- over 600 houses flooded
- 16 farms evacuated
- residents evacuated to temporary accomodation for several months.
Economic:
- Somerset county council estimated the cost of damage at £10 million
- over 1400 hectares of agricultural land was under water for 3-4 weeks
- over 1000 livestock evacuated
Environmental:
- Floodwaters were heavily contaminated with sewage and other pollutants
- a huge amount of debris had to be cleared
- stagnant water had to reoxygenated
Climate Change:
Causes of climate change
Natural causes of climate change:
Natural causes:
The Milankovitch cycles - The Milankovitch Cycles are natural changes in Earth’s orbit and tilt, including eccentricity (orbit shape), axial tilt (angle of Earth’s axis), and precession (axis wobble). These cycles, occurring over tens of thousands of years, affect solar energy distribution and drive climate changes like ice ages and warmer periods.
Solar ouput - solar output depends on the number of sunspots. When there are more, the sun gives off more heat and solar flares and vice versa.
volcanic activity - when volcanoes erupt sulphur dioxide is released which reacts with water vapour to become volcanic aerosol, reflecting sunlight away and reducing temperatures.
Climate change:
causes of climate change
Human causes of climate change:
Fossil fuels:
burning fossil fuels for electricity releases carbon dioxide and accounts for 50% of greenhouse gas emissions
Agricultures:
Produces large amount of methane through cattle and rice paddy fields
Deforestation:
- slash and burn released the carbon stored by trees
- trees no longer act as carbon sinks, removing carbon dioxide via photosynthesis
Living world
Tropical rainforests
Plant and animal adaptations in the rainforest:
Plant:
- drip tip - leaves have pointy tips to allow water to run off without damage
- Buttress roots - large roots have ridgeswhich create a large surface area to support trees
- epiphytes - plants that live on branches in the canopy and get nutrients from air and water
Animal:
- sloths - they use camouflage and move slowly for safety
- sipder monkeys - have long, strong limbs that allow them to climb rainforest trees
- toucan - a long, large bill that allows it to reach and cut fruit from branches
living world:
caste study of a tropical rainforest: The Amazon
Causes of deforestation:
Logging:
- timber companies log mahogany and teak for furniture
- selective logging of mature trees is sometimes used
- smaller trees are used as wood for fuel or charcoal, for which clear felling is used
Mineral extraction:
- gold and bauxite are mined in the amazon
- there are now over 50,000 hectares of land being used for gold mining
Energy development:
- dams have been built to generate HEP
- This floods large areas of rainforest and dams don’t last long as turbines get blocked by soil washed down from deforested slopes
Commercial farming:
- cattle farming accounts for 80% of deforestation
- land is also cleared for crops such as: palm oil, bannanas, coffee. and soybean
Subsistence farming:
- generally uses the tradtitional slash and burn technique
- small scale impact, but fires can get out of control, clearing larger areas of land
living world
tropical rainforests
Impacts of deforestation:
loss of biodiversity:
- the amazon could lose 30-45% of their main species by 2030. This also causes loss of undiscovered plant species that could be used for medicine
Soil erosion:
- deforestation exposes the thin topsoil which is quickly removed by heavy rainfall. Soil erosion also leads to large amounts of silt in the river, impacting the river ecosystem and leading to more flooding
- the soil aslo loses its fertility as less biomass makes the topsoil, and cattle grazing and plantations further reduce soil fertility which means plantations and pastures are abandoned and more deforestation takes place
contribute to climate change:
- deforestation means that the tree canopy will no longer absorb carbon dioxide
Living World
Tropical rainforests
Deforestation also has economic impacts, both negative and positive:
Economic gains:
- job creation - in construction and operations
- tax revenue used to supply public services
- improved transport infrastructure benefits development and tourism
- HEP is cheap and plentiful
- minerals are valuable
Economic losses:
- fires pollute and destroy large areas of valuable forest
- rising temperatures could devastate established farming
- plants that could form the basis of hugely profitable medicines may become extinct
- rainforest tourism could decrease
Living world
Strategies used to manage the rainforest sustainability
Strategies used to manage the rainforest sustainability:
Selective logging and replanting:
- only mature trees are cut down, so clear felling doesn’t take place, and trees are replanted
Conservation and education:
- Rainforests can be designated as national parks or natural reserves, which protects them from illegal activities such as illegal logging.
Ecotourism:
- It introduces people to the natural world and benefitrs the local community. The income generated through ecotourism makes it a sustainable investment even when compared to deforestation for short term profits.
Living world
Cold environments - case study
case study svalbard, norway:
opportunities for development in Svalbard include:
