Geography AQA PAPER 1

Natural Hazard

Natural Hazard

Any natural process that is a potential threat to human life and property

Factors affecting hazard risk

Urbanisation, poverty, development, climate change

Constructive plates

Two plates move apart, magma forces way along gap and causes earthquake, erupted lava cools and forms volcano

Ecotourism

The practice of using an area's natural environment to attract tourists which is sustainable and won't damage area

Destructive plate

Two plates moving towards one another, oceanic plate subducts under continental plate and friction causes melting of oceanic plate, triggers earthquake

Conservative plate

Two plates moving alongside, friction can send shockwaves causing earthquakes

Where are volcanoes distributed?

Coastline and tectonic plate boundaries

Where are earthquakes distributed?

Coastline and tectonic plate boundaries

Chile HIC earthquake

27th feb 2010, 8.8 Richter scale, caused on destructive plate margin PE- 5000 deaths, Santiago airport damaged SE- 1500km road damaged by landslide IR- Emergency service floating bridge, field hospitals LTR- President said 4 years to recover

Nepal LIC earthquake

25th april 2015, 7.9 Richter scale, caused by collision of eurasian and Australian plate PE- 3 mil homeless SE- Avalanche 250 missing IR- Social media search, field hospitals LTR- Homeless rehoused, tourist site reopened

Why would people live next to natural hazards?

Rarity of volcano explosion, poverty, fertile flood plain soils

How to reduce risk from tectonic hazard

Monitoring- using scientific equipment to detect warning Prediction- historical events Protection- designing buildings Planning- identifying and avoiding places at risk

Coriolis effect

The effect of Earth's rotation on the direction of winds and currents.

Formation of a storm

26 degrees water, close to equator, warm ocean heats air causing it to rise, water evaporates from hot surface, so rising air contains water vapour, air starts to spin, eye is calm

Where do storms form?

5-15 degrees north and south of equator because there is not enough spin from the rotation of the earth elsewhere

What 3 features can climate change effect in a storm?

Distribution, frequency, intensity

Typhoon Haiyan

November 2013, category 5, Philippines PE- Tacloban airport damage SE- Looting and violence IR- Red cross gave food LTR- Oxfam supported fishing boats for income, cash for cleaning city

Somerset Levels Flood

Jan 2014 South West, caused by wettest Jan and low pressure driven across Atlantic ocean Social- 16 evacuated farms, no power Economic- £10m Environmental- Debris to be cleared IR- Villagers used boats to be evacuated LTR- £20m action plan to prevent flood by government

Dam construction (preventing flood)

Water is held back in a dam and released in a controlled way, is expensive, makes hydroelectric power, agricultural land lost

River engineering (preventing flood)

River may be widened or deepened to carry more water or straightened to flow faster, altering could lead to flood downstream

Afforestation (preventing flooding)

Trees planted to increase interception of rain water

Managed flooding (preventing flooding)

River floods naturally in places to prevent areas like settlements being flooded

Evidence of climate change

Rising sea level of 10-20cm in 100 years, seasonal change eg flowering takes place at a different time, shrinking glaciers most will be gone by 2035

Causes of climate change- natural

Changes in earths orbit, varied heat output from sun, volcanic activity ash blocks out sunlight

Causes of climate change- human

Burning fossil fuels and realising co2 or deforestation

Effects of climate change on people

Can bring weather hazards and take lives or property. eg rainfall brings mosquitoes and malaria

Managing climate change

Carbon capture and storage technology to capture co2 from burning fossil fuels, using alternative energy resources, planting trees, international agreement

Epping Forest

North East of London on Essex border, 4km wide, deciduous woodland, vegetation determined by climate

Primary producer

Organisms that produce energy available for other organisms to eat eg plants and photosynthesis

Consumers

Get energy by consuming other organisms

Nutrient cycle

The movement and exchange of organic and inorganic matter back into the production of living matter

How can change affect an eco system?

Natural- drought dries out lake Human- eutrophication

Tropical rainforest distribution

Close to equator high temp heavy rainfall due to low equatorial pressure belt

Desert distribution

30 degrees north and south of equator sub tropic high pressure belts sinking air stops cloud forming

Deciduous and coniferous

50-60 degrees north of equator shed leaves in winter to retain moisture

Temperate Grassland distribution

30 degrees north and south of equator warm dry summer grass can tolerate because used for grazing animals

Mediterranean distribution

40-45 degrees north of equator hot summer due to pressure belts moving north and south throughout year

Tropical grassland (savanna) distribution

15-30 north and south of equator low latitudes dry season hot fires thunderstorms in wet season

Tundra distribution

From Arctic circle to 60-70 degrees north low growing plants adapted to cold

Where is the Malaysian Rainforest?

South East Asia

Example of Malaysian rainforest plant adaptation

Fan palms have large fan shaped leaves good for catching sunshine and water leaves are segmented to drain excess water

Example of Malaysian rainforest animal adaptation

Sloths have longer arms than legs to grab branches grooved fur and inactive lifestyle helps growth of algae to camouflage

Threats to the Malaysian rainforest

Commercial logging for palm oil, subsistence farming tribes burn trees to clear land, mineral extraction drilling for oil and gas, road building trees cut down

Impacts of threats on Malaysian rainforest

Soil erodes and becomes loose and infertile, loss of biodiversity and medicine, contribution to climate change

Economic gains of deforestation

Improved transport, hydroelectric power, minerals are valuable, palm oil industry benefits

Economic losses of deforestation

Medicine loss

Why manage rainforests?

Medicine, to keep biodiversity, water sources, tribes, reduce rate of global warming

How to manage the Malaysian rainforest

Selective logging and afforestation, conservation and education (preserving rainforest), international agreements, Ecotourism, Forest Estates have been created by the government where no change of land use is allowed, Creation of National Parks to protect biodiversity

Thar Desert

North West India most densely populated desert in the world

How plants and animals adapt in the Thar desert

Snakes retain water with waterproof skin and most rodents are nocturnal. Cacti have waxy skin to reduce water loss and store water in roots and stems

Challenges of the Thar desert

Temperature- working in high temperature hard for farmers and lead to water shortage Water supply- as a population and farming industry grows water need increases Accessibility issues- limited roads tarmac would melt

Opportunity of the Thar Desert

Minerals like gypsum can be used for cement, tourism camels for money, energy development solar panels, farming crops like wheat

Causes of desertification

Erosion, overgrazing, drought, soil compaction, agriculture

Managing desertification

Afforestation binds soil together leaves and branches give shade to animals, decrease livestock, manage grazing

How do waves form?

Waves form by wind blowing over the sea and the friction causes ripples

Freeze thaw weathering

Water flows into cracks and freezes cracks then is weakened and is easier to be eroded

Constructive waves

Deposit large amounts of sand and pebbles construct beaches strong swash (spilling)

Destructive waves

Formed by storms can destroy beach removing pebbles with strong backwash (plunging)

Mechanical weathering (cliffs)

The disintegration (break up of rocks) eg freeze thaw

Chemical weathering (cliffs)

Caused by chemical changes eg rain water is acidic

Biological weathering (cliffs)

Plants growing in cracks and animals burrowing in weak rock

Rockfall (mass movement)

Fragments of rock break away from cliff face due to freeze thaw

Landslide (mass movement)

Blocks of rock slide downhill

Mud flow (mass movement)

Saturated soil and weak rock flows down slope

Rotational slip (mass movement)

Slump of saturated soil and weak rock along a curved surface

5 kinds of coastal erosion

Solution, corrosion, abrasion, attrition, hydraulic power

Solution

Dissolving of rocks due to chemicals in water

Corrosion

Fragments of rock picked up and hurled at cliff

Abrasion

Sandpapering pebbles grinding against platform until smooth

Attrition

Pebbles carried by sea knock against each other to be smaller and rounder

Hydraulic power

Trapped air forced into holes cracks rock

Coastal transportation 4 kinds

Solution; Suspension; Traction; Saltation

Solution

Dissolved chemicals from limestone or chalk float in water

Suspension

Particles suspended in water

Saltation

Hopping or bouncing motion of particles too heavy to suspend

Traction

Rolled pebbles

Longshore drift

Swash carries sediment up beach backwash carries sediment back down as waves draw back at 90 degrees

Headlands and bays

Different types of rock erode at different rates softer rock erodes to a bay whilst resistant rock becomes a headland

Wave cut platform

A flat area of rock in front of a cliff created by cliff retreat

Stack formation

Hydraulic action crack, cave, arch, stack, stump

Sand dunes

Hills of sand shaped by the wind

Spits

Thin lines of sand deposited by long shore drift strong winds cause curve in sheltered bit behind spit there may be a salt marsh

Bars

Longshore drift caucuses spit to grow across a bay trapping a lake behind it causing a bar waves deposit sediment due to friction with seabed, build up of sediment cause wave to break from coast

Sea wall (coast defence)

Concrete protect cliffs, waves can erode it and it is expensive and ugly

Gryone (coast defence)

Wooden fence built at right angles in beach, prevents long shore drift but can create erosion down the cost, unattractive and expensive

Gabions (coast defence)

Steel mesh cages filled with small rocks, absorb wave energy. Inexpensive not attractive

Beach nourishment (coast defence)

Dumping new sand onto eroding beaches to restore them, needs maintaining and is costly

Managed retreat (coast defence)

Certain areas can flood is natural but is required to compensate those who lose land

Beach stabilisation (coast defence)

Planting dead trees in sand widens beach but requires maintenance

Dune regeneration (coast defence)

New sand dunes which absorb wave energy but results in land loss

Lyme Regis coastal management

Small coastal town south coast famous for fossils popular tourist place Issue is that the town is on an unstable cliff, it is being managed by the council who provide coastal protection and reduce threat of land slips. Winter 2003-2004 £1.4 mill project to stabilise cliffs nails used to hold rocks together and improved draining and re profiling of beach slope Outcomes new beaches increased tourism, new defences, new tourists led to conflict with traffic and litter, defences are ugly

Drainage basin

An area drained by a major river and its tributaries

Source

Start of a river

Tributary

A stream or river that flows into a larger river

Confluence

Where a tributary joins a larger river

Fluvial river processes

Hydraulic action, abrasion, attrition, solution from limestone or chalk

Deposition

Occurs when the velocity decreases and there is no more energy

Interlocking spurs

Areas of high land which stick out into a steep-sided valley

Waterfalls

Soft rock erodes more quickly undercutting hard rock and hard rock over hangs and eventually collapses fallen rock goes into plunge pool

Meanders

A winding, looping curve in the course of a river on soft, flat flood plain