CIE IGCSE Geography Natural Environment 5 markers

features of a stratovolcano

steepsided, viscous lava, explosive, layers of ash and lava, destructive plates

features of shieldvolcano

gently sloping sides, runny and thin lava, less explosive, frequent eruptions, conservative plates

dangers of volcano

lava, ash, pyroclastic flow, lahars, volcanic bombs

opportunities of volcano

beauty, jobs from tourism, mining, fertile land, geothermal energy,

reducing impacts of volcano

thermal imagery and temperature can predict, hazard mapping and risk zones

hazards of earthquake

ground shakes, landslides, building fall, tsunamis, fires, infrastructure destroyed

why people still live near earthquake(applies to volcano too)

employment, sentiment, friends and family, cannot afford to move, confidence in protection methods, don’t think risk is high enough/will happen

reducing impacts of an earthquake

prediction, seisometers, preparation, early warning drills, protection - steel frames means buildings can sway, deep foundations means less likely to collapse, shock absorbers absorb tremors, shatteproof windows less likely to be injured by glass breaking

types of erosion

1. erosion is the wearing away of rock by natural processes

2. hydraulic action, water forces its way into cracks and causes pressure which makes the cracks bigger and large pieces of rock fall off

3. abrasion, rocks carried by water wear bed and banks down thru a sandpaper action

4. attrition, material in load hits other material and gets smaller and more rounded

5. solution, minerals in rocks get dissolved

types of transportation

transportation is the movement of eroded material in a rive

1. traction, large material rolled along river bed, not enough strength to pick up

2. saltation, load bounces along river bed

3. suspension, material held up and carried in river flow

4. solution, river carries dissolved sediment

deposition

river loses energy as it gets slower, puts load down on bed banks floodplain

v shaped valley formation

1. vertical erosion occurs due to low discharge

2. weathering attacks valley sides

3. gravity pulls weathered material into river

4. increased load = increased erosion

5. further vertical erosion and erosion of sides

6. steep v shaped valley formed

Waterfalls and gorges

1. hard rock lies over soft rock

2. soft rock erodes quicker as less resistant

3. steep gradient and waterfall created

4. rock is undercut

5. plunge pool formed below

6. rock collapses under own weight

7. waterfall retreats

8. over time steep sided valley - gorge - forms

potholes

hollows in river bed

1. sediment scours bed

2. depressions exist

3. eddies(swirls) form

4. pebbles spin and erode downwards#

5. hollow/pothole formed

meander and oxbow lake

1. water flows faster on outside bend of river, as deeper water = less friction

2. erosion occurs here

3. inner bend is shallower, slower water due to increased friction

4. deposition occurs here

5. helicoidal flow takes neroded material to shallwo side

6. slip off slope formed on inner bend, river cliff other side

7. bend gets more pronounced as this continues

8. neck of meander narrows

9. when water levels high, river cuts across meander

10. new chaneel formed with loop

11. sediment deposited on inner bend where loop connects

12. loop is cut off from river and oxbow lake forms

floodplains and levees

floodplain is flat land next to river in lower course formed by lateral erosion and deposition. levees are mounds of deposited sediment

1. when a river floods it deposits load on floodplain as energy lost

2. biggest deposited first

3. sediment builds up and forms mounds

4. levees, or large natural embankments close to the channel form

5. made of sand, silt and clay - alluvium

delta

1. depositional landform at river mouth, when river meets sea must slow down

2. depositionn occurs

3. if material not washed away builds up and blocks channel

4. delta formed as channel splits in varies different ways

5. topset, foreset, bottomset beds, with going from coursest and shortest to finest and furthest

6. arcuate is fan shapeed, birds foot is lots channels jutting into sea, curspate is a arrow channel with sides eroded

causes of flooding

heavy consistent rain, rapid snowmelt, steep slopes, saturated ground, deforestation, urbanisation

impacts of flooding

food shortages, injury and death, property damage, power cuts, contamination of water, ecosystems destroyed

managing flooding - hard engineering

barriers and floodwalls, embankments, levees all allow river to hold more water before flooding

canals and waterways increase chanel and control where water goes,

dredging and straightening removes meanders, crosses faster and more channel

dams control flow by blocking

managing flooding - soft

afforestation, water interception thru trees

water allowed to flow into less valuable areas such as washlands

land use zones, certain buildings allowed at certain distances relative to how valuable it is and risk

opportunities of a river

agriculture, trade, HEP, jobs thru tourism, transport, domestic uses such as cooking cleaning washing drinking

what affects a coasts shape

rock type, coastal defences, power of waves

what affects wave energy

wind speed, distance of open water where wind is blowing - fetch - length of time wind has been blowing

destructive waves and beach formed

high energy, high, strong backwash and weak swash, destroys beach, drags material back, steep beach

constructive waves and beach formed

flat, low, low energy, strong swash and weak backwash, deposition and gently sloping beach

cove formation

concordant coastline, layers of rock parallel to coastline, hard rock eroded slowly, breaks through to soft rock, erodes more, cove formed

headlands and bays

1. discordant coastline, alternating layers of soft and hard rock perpendicular to coastline

2. soft rock less resistant so eroded quicker

3. hard rock more resistant so eroded slower

4. headlands and bays formed, headland are bits of hard rock jutting out, bays between them where soft rock eroded

wave cut platforms and cliffs

1. water erodes the base of cliff of the coast at high water mark

2. wave-cut notch formed, wave has undercut rock

3. further erosion makes cliff above unstable

4. cliff collapses, waves carry away eroded material

5. wave cut platform forms

6. process repeats, cliff and coast retreat

caves arches stacks and stumps

1. happens on a headland, waves are refracted and attack sides of healand

2. attacks any weaknesses/cracks, opens up a large crack through hydraulic action

3. grows into a cave through widening of crack and erosion

4. gets larger, breaks through headland to form arch

5. arch foundation gets thinner and wider due to erosion and weathering

6. arch collapses and forms a stack

7. eroded and forms a stump

process of longshore drift

1. waves approach beach at angle due to prevailing wind, swash approaches at this angle

2. waves hit coastline and travel up beach, swash moves sand in this direction

3. backwash comes straight back down the beach due to gravity so moves sand back down

4. process repeats, material moved along beach in zig-zag manner

spit formation

1. material is moved along beach through longshore drift

2. Once they reach a headland/change in coast shape, material is deposited in calmer water here

3. more deposition occurs as result of higher friction

4. spit extends in length, marshes develop behind it with salt loving plants’ roots keeping mud together

5. wind may change direction and form hooked end

6. fully extended when force of tide prevents any more deposition

sand dune formation

A loose sand hill stabilised by vegetation. Needs constructive waves for deposition, large supply of sand, high tidal range, marram grass and obstacles

1. Windblown sand is deposited against an obstruction such as driftwood

2. More sand particles are caught

3. Dunes grow in size

4. Vegetation begins to grow e.g. marram grass, more stable

5. traps more and gets larger over time

6. dunes get bigger and bigger, as more and more plants grow, with organic matter growing. embryo → fore → yellow → grey → mature

coral reefs - location and characteristics

diverse underwater ecosystem, made of coral polyp and exoskeleton of limestone, algae live inside with symbiotic relationship (respiration and photosynthesis). grows upwards, located 30 degrees north and south

coral reefs conditions required

1. warm water between 18-27 - encourages year round growth

2. shallow water not more than 60m deep - sunlight can penetrate

3. water free from sediment - not damage coral

4. plentiful supply of oxygen and plankton - so organisms can grow and food supply

5. calm water - prevents destruction of coral

6. alkaline water 8 and above - acidic water kills coral

coral reef opportunities

habitats for species, sea food, tourism, coastal protection, medicinal compounds, shells can be used in jewellery

coral reefs threats and management

pollution from sunscreen, overfishing, used in jewellery, damage from tourists trampling, sand and limestone used in construction

reduce greenhouse gases, marine protected areas, reef restoration projects, public awareness campaigns, coral safe sunscreen

mangroves location and characteristics

shrubs/trees that grow on coast in equatorial conditions, adapted to salty conditions, 30 N and S. densely packed trees with aerial roots and shiny leaves grow in shallow muddy water

mangrove conditions needed to survive

1. temp above 20 degrees, temp range max 5

2. gentle wave action, no strong currents

3. high salinity

4. large tidal range

5. low shore slope

mangrove value

used for coastal protection from storms and erosion, food, fuel, tourism, medicinal compounds

mangrove hazards and management

pollution, increased salinity due to climate change, cleared for better beach view, converted to rice paddies, overharvested for fuel

protected areas, education, restoration campaigns, penalties

opportunities of the coast

1. agriculture - flat and fertile land

2. jobs and local income for fishermen

3. tourism as people want to go to sandy beaches

hazards of the coast

1. erosion, land retreats, things at risk

2. mass movements like rock falls cause death

3. flooding destroys crops

4. tsunamis destroy livelihoods

5. hurricanes and storms, PTSD

managing coastal erosion

sea walls and rock armour, gabions reflect wave energy/ absorb wave energy

groynes prevent longshore drift, sand remains on beach, friction, absorb wave energy

cliff regrading, cuts cliffs and gentle slopes to stop slumping

beach replenishment, place sand and pebbles on beach

managed retreat, low value areas allowed to be eroded to protect land in other areas

dangers of a tropical storm

1. death/injury

2. habitats destroyed

3. floods destroy homes

4. infrastructure destroyed

5. evacuation and homelessness

stevenson screen location and reasons

1. white, reflects sunlight to prevent instruments inside heating up

2. slats, allow air to circulate freely for accurate temperature and humidity

3. elevated, prevent it from being distorted from ground heat and protect it from being damaged

4. in the open, away from buildings which give off heat and trees which cause shadow, away from public/fenced to prevent tampering with

cloud types

cirrus = high, alto = medium, stratus = layers, cumulus = heaped, nimbus = rain and dark

rainforest ecosystem

1. high biodiversity, 50-80% of worlds species

2. not very fertile soil, constantly leached, but nutrients rapidly cycled due to high decomposition. top layer is fertile, but no build up

3. ground 0m, shrub 10m, under canopy 15m, canopy blocks sunlight, 30m, emergent = 45m

hot desert ecosystem

1. low biodiversity as few plants can grow there

2. little plant growth due to extreme temps and low water

3. lack of organic matter so soil is lacking in nutrients, course and sandy