Geography (paper 1) 🌍 Flashcards
(258 cards)
1
Q
[Ecosystems]
Decomposers meaning
A
Organisms that break down organic matter (eg bacteria)
2
Q
Nutrient cycling
A
When nutrients are passed down from one component of an ecosystem to another
3
Q
Where is Epping Forest located?
A
North East of London
4
Q
Characteristics of Epping Forest
A
Deciduous forest that consists of trees 100s of years old: Its leaves fall in the winter conserve energy and its leaves expand its surface area in summer to absorb more sunlight
5
Q
Biomass
A
Energy stored in living things
6
Q
Weathering
A
When rocks are broken down and its nutrients enter the soil
7
Q
Surface runoff
A
When water flows on the surface washing away nutrients
8
Q
Leaching
A
When nutrients are washed out of the soil by the rain
9
Q
How do nutrients enter the soil?
A
Weathering and the decomposition of leaves (from leaf litter)
10
Q
How do nutrients get stored as biomass?
A
When plants absorb nutrients from the soil using its roots
11
Q
How do nutrients get stored in leaf litter?
A
Through precipitation and when leaves drop in autumn (from biomass)
12
Q
What are 2 ways nutrients can leave an ecosystem?
A
Surface runoff and leaching
13
Q
How are nutrients cycled around Epping Forest?
A
Nutrients enter the soil and then gets stored in biomass and then in leaf litter in a recurring process
14
Q
Abiotic component meaning
A
non - living things
15
Q
Examples of abiotic components
A
• Water • The Sun • Rocks • Soil • Air
16
Q
Functions of abiotic components
A
• Water - helps plants to photosynthesise • Sun - provides light for growth • Rocks - provides habitats • Soil - provides nutrients • Air - helps organisms to respire
17
Q
Endemic species meaning
A
Plants & organisms that are only found in a certain biome
18
Q
[Tropical rainforests]
Reason for the distribution of tropical rainforests
A
• The sun is directly overhead all year therefore it’s rays are more concentrated here
• So the climate is hot and wet which provides the perfect conditions for plant growth
19
Q
Describe the process of convectional rainfall
A
Warm air rises > the air cools > water vapour condenses > clouds and rain are formed
20
Q
Why are hot deserts found either side of tropical rainforests?
A
Cool, dry air disperses from rainforests and starts to descend on deserts
21
Q
Why are there high levels of biodiversity in tropical rainforests?
A
Hot and wet conditions make it optimal for plant growth
22
Q
Why does soil tend to be infertile in tropical rainforests?
A
Nutrients in the ground are quickly taken up by the roots of many plants • Leaching also occurs
23
Q
Characteristics of the emergent layer
A
•Trees with wide, strong buttress roots (for stability in windy conditions) • Tallest trees • Its seeds are winged to be carried by the wind
24
Q
Characteristics of the canopy layer
A
• Home to 90% of organisms in tropical rainforests • Blocks out sunlight from layers below • Epiphytes found here (plants that grow on trees) • between 15 and 30 metres high
25
Characteristics of the under canopy layer
• Receives little sunlight as canopy blocks it out • Lianas (vines) climb up trees to get pollinated by insects and reproduce
26
Characteristics of the ground / shrub layer
• Humid and dark • Leaf litter is quickly decomposed by the humidity • soil is infertile • 2% of sunlight reaches this layer
27
Adaptations of drip tip leaves
Have a pointed tip to allow water to slide down the leaf in order to:
• help the water be absorbed by the roots
• prevent the leaves from breaking
28
Adaptations of epiphytes
• Its roots grow into the air to absorb the air’s moisture and nutrients
29
Adaptations of the howler monkey
• Prehensile tail supports its grip as it swings • Long limbs to swing rapidly when escaping predators
30
Adaptations of the tree frog
• Long tongue to catch prey • Toe pads made of mucus to stick to trees and plants
31
Adaptations of the three toed sloth
• Very slow moving to conserve energy • Moss grows on its fur to help the sloth camouflage to avoid being detected by predators
32
Biome meaning
A large ecological area
33
What’s a tropical rainforest?
Rainforests at the equator with a warm climate and high levels of precipitation
34
Biodiversity meaning
A measure of how many different species live in an ecosystem
35
Why is the climate of a tropical rainforest valuable globally?
• It supports the growth of a large number of trees (which grow food resources eg cocoa, sugar and banana)
• They act as a carbon sink (absorbs and stores co2 which reduces global warming)
36
Why is medicine processed from tropical rainforests valuable for social sustainability?
Some plants in rainforests (such as the rosy periwinkle) contain anti cancer properties used for cancer fighting drugs • This improves life expectancy
37
Why is water from tropical rainforests valuable?
20% of the Earth’s fresh water is found in the Amazon Basin
38
Deforestation meaning
When trees are cut down at a large scale
39
Loss of rainforest in countries around the world
Brazil has lost 89000 square miles in 17 years • Indonesia has lost 35000
40
Why is deforestation happening at a faster rate in some countries compared to others ?
• Space provision for urbanisation during population growth
• Illegal logging
• Laws protecting rainforests
• Economy might depend on it for income
41
How has the rate of deforestation in the Amazon changed?
In 2004 it was high due to commercial farming (cattle) for TNCs like Mac D • Lowest in 2012 as Brazil invests in reducing climate change and increasing tourism • Increases in 2020 as new president (Jair Bolsonaro) encourages agriculture and mining activities
42
Causes of deforestation in the Amazon
• Commercial farming (*to make money*) **(**accounts for 80% of deforestation**)**
• Subsistence farming (*for survival*)
• Logging
• Hydroelectric-power
• Mining
• Urbanisation
43
Process of how deforestation affects the soil in a rainforest
Trees are cut down -> No roots are available to hold soil together -> Soil is exposed to the rain -> Nutrients are leached from the soil -> Plants are unable to regrow -> Land becomes unusable
44
Negative impacts of deforestation in the Amazon
• Only 240 tribes left (the indigenous losing their homes)
• Fewer trees to absorb co2
• Soil is exposed to heavy rain (leaching can occur)
• 50,000 species are becoming extinct every year
• Local climate gets drier (fewer trees to release water into the air)
• Conflict arises between loggers and the indigenous
45
What’s the biggest flow of nutrients out of the rainforest and why?
• Leaching • High levels of precipitation due to convectional rainfall
46
Sustainable rainforest management strategies
• Selective logging • Ecotourism • Conservation and education • Debt reduction • International agreements
47
What is selective logging and how sustainable is it?
• **Only felling** (cutting down) **trees when they are fully grown and letting younger ones mature** • Not environmentally sustainable as it can take around 50 years for trees to regrow
48
What is *conservation and education* and how sustainable is it?
• **The preservation of rainforests through national parks or reserves which allows for scientific research** • The environment is left untouched
49
What is ecotourism and how sustainable is it?
• **Tourism that allows people to experience the natural environment without damaging it**
• Local people earn money working as guides
• Tourists are educated about conserving the environment
• Accommodation is built using local materials
50
What are international agreements and how sustainable are they?
•**Agreements between countries made to protect the rainforest** • Not economically sustainable as the trading of valuable hardwood is restricted
51
What is a debt for nature swap and how sustainable is it?
• **Where HICs convert LICs’ debt into a fund to protect tropical rainforests** • Environmentally and economically sustainable (LICs can focus on development rather than paying debt)
52
What’s another way of saying an environment that’s difficult to survive in?
Hostile environment
53
Stakeholder meaning
Someone who has an interest in an issue
54
Biosphere reserve
When the central areas of a forest are protected but forms of activity are allowed on the outer zones
55
[Hot deserts]
Physical characteristics of a hot desert
• Hot and arid climate
• Low levels of precipitation
• Water is often found deep underground in aquifers
• Plants (Cacti) have deep tap roots to absorb water underground
• Animals are adapted to survive without food/water for a long time
• High levels of solar insolation
56
How is the soil eroded in hot deserts?
High wind speeds that occur during sandstorms
57
What do camels store in their humps to survive in a desert?
Fat
58
Where is the Western Desert located?
Nevada, Texas
59
How are cacti adapted to a hot desert environment?
• Large spikes to deter consumers from wanting to eat it (so it survives and continues to grow)
• Have spikes instead of leaves to reduces surface area and water loss (because water quickly evaporates in the hot climate)
• Stores water in stem to survive long periods without rainfall (as precipitation levels are very low in deserts)
60
How are bactrian camels adapted to survive in a hot desert environment?
• Humps store fat to survive long periods without food or water (because vegetation is difficult to find in an arid climate)
• Two rows of eyelashes to prevent sand from blowing into its eyes
• Thick fur all over body to reduce heat loss at night (as the temperature plummets due to a lack of clouds for humidity)
61
Characteristics of desert soil
**Unconsolidated** (loose because there’s only a few trees to bind the soil together) and **fertile** (because no leaching occurs)
62
What conditions are required for a desert environment?
• High pressure • Cool air sinking
63
Irrigation meaning
Extracting water from aquifers for agriculture
64
Opportunities for developing hot deserts
• Mineral extraction
• Agriculture
• Energy
• Tourism
65
Challenges associated with developing hot deserts
• Extreme temperatures
• Limited water supply
• Inaccessibility
66
How is mineral extraction able to take place in the Western Desert?
• It’s rich in minerals like copper, uranium, zinc • Minerals are close to the surface of the ground therefore *open cast mining* can take place
67
How is agriculture able to take place in the Western Desert?
• High temperatures and water provided by irrigation makes it ideal for farming
68
Sources of irrigation in a desert (eg Western Desert)
• Water stored in **aquifers** can be brought to the surface by digging a well
• **Canals** are used for large scale agriculture
69
How is tourism able to take place in the Western Desert?
• Many tourist attractions such as the Grand Canyon (9 million visitors a year), Lake Mead and Lake Powell (2 million)
• Las Vegas attracts 37 million
• Tourism is the Western Desert’s most important source of income
70
How is energy able to be supplied in the Western Desert?
• Sonoran Solar Project in Arizona is a new solar power plant project that will help power 100,000 homes
• Hoover Dam generates hydroelectricity from Lake Mead
• Fossil fuels like oil is drilled for in Arizona (25 active oil production sites also located on land owned by the Navajo people)
71
How do extreme temperatures present a challenge for development in the Western Desert?
• Infrastructure requires to be resistant to heat • Difficult for Native Americans to settle • Temperatures reach as high as 50C
72
How does inaccessibility present a challenge for development in the Western Desert?
A lack of roads make it difficult to transport resources and tourists to enter
73
How does a limited water supply present a challenge for development in the Western Desert?
• Makes it difficult for agriculture to take place without access to aquifers • Can lead to droughts which will inflict job losses in farming
74
Meaning of solar insolation
The sun’s rays are easily able to reach the ground as there’s no clouds
75
Types of hardwood trees in tropical rainforests
Timber trees: Teak and mahogany
76
How does deforestation affect water supplies?
Chemicals like mercury used in mining can poison the ecosystem and pollute the water
77
Positive impacts of deforestation in the Amazon
• Minerals such as gold, copper and tin from mining can be exported to make money
• Roads being built improves trade and transport (eg Trans-amazon highway)
• Hardwood is a valuable resource to export
• Almost a 1/4 of Brazil’s GDP comes from activities in the Amazon’s deforested areas
78
How does the Amazon have high levels of biodiversity?
It contains half of all the plants and animals in the world
79
Desertification meaning
When land turns into a desert because it dries out and loses its nutrients
80
Causes of desertification
• Population growth • Deforestation • Soil erosion • Fuelwood • Overgrazing • Over - cultivation • Drought • Climate change
81
How does overgrazing contribute to desertification?
The cows trample on the soil compressing the nutrients • When it rains, water cannot infiltrate the soil • Therefore water flows on the surface (surface runoff) and nutrients are leached from it
82
Overgrazing definition
When farmers have large herds of cattle
83
How does over-cultivation contribute to desertification?
Having a large number of crops would mean that more nutrients are absorbed from the soil which degrades it and makes it infertile
84
How does soil erosion contribute to desertification?
• Without roots binding the soil together, the soil is easily eroded by the wind (as its unconsolidated) • The soil is also exposed to heavy rainfall which means that leaching occurs
85
Fuelwood meaning
Burning wood for fuel eg cooking
86
How does fuelwood and climate change contribute to desertification?
• When wood is burned, greenhouse gases are released • This increases the temperature of the atmosphere • Causing hot areas to become even hotter and drier
87
What are the solutions to prevent desertification in the Sahel?
Zai and drip irrigation • Bunds • Education (cattle farming) • Afforestation • Intermediate technology • Renewable energy
88
What is zai and drip irrigation and how does it prevent the soil from degrading?
•Zai involves digging small holes at the base of each plant to catch rain
• Drip irrigation is a system of pipes with small holes at base of each plant
• Less water is wasted as water is only provided for the plant and doesn’t evaporate in the hot conditions
• This helps the soil keep its water and nutrients
• Form of intermediate technology
• Done on small scale
89
What are bunds and how does it prevent the soil from being degraded?
• They are small walls built out of rocks to prevent surface runoff on slopes
• It ensures the water infiltrates the soil to provide nutrients and make it fertile
• Its a cheap solution but can’t happen on a large scale
90
What is afforestation and how does it prevent the soil from degrading?
• It’s when trees are planted to restore degraded land
• Eg Great Green Wall in the Sahel (Continuous wall of trees from east to west Africa)
• The soil becomes consolidated as the root of plants bind it together, preventing leaching
• It reduces soil erosion but it can take a long time for trees to grow
91
How does intermediate technology prevent the soil from being degraded?
• Stoves are provided for people in LICs instead of burning wood
• Less trees are cut down (so less soil is exposed to rain for leaching)
• Less greenhouse gases are produced (less fuelwood burned)
• Reduces climate change and the loss of nutrients
• Environmentally and socially sustainable (people can cook more efficiently)
92
[River landscapes]
Abrasion meaning
When large rocks hit and scrape against the river bed and banks
93
Deposition meaning
When a river drops the material it’s carrying because it loses energy
94
Lateral erosion meaning
When the river has lots of energy to erode the sides making the river wider
95
Long profile meaning
A cross sectional view of a river from source to estuary
96
What is the name for the sides of a river?
The river bank
97
What is the name for the bottom of a river?
The river bed
98
Vertical erosion meaning
When the river cuts down into the landscape
99
What is a V-shaped valley?
A steep sided valley created by vertical erosion near the source of a river
100
Flood plain meaning
Low lying land either side of a river which regularly floods
101
Drainage basin meaning
The area that feeds the river
102
Tributary meaning
A small river that feeds the main one
103
Estuary meaning
When the river flows into the sea
104
Watershed meaning
The line where 2 drainage basins meet
105
Source meaning
Starting point of a river
106
Features of a river at its source
• Always in hills/mountains • Flows through a V-shaped valley (vertical erosion) • Low velocity • Shallow and narrow channel • Steep gradient
107
Features of a river at the estuary
• At sea level • Flat gradient • High velocity/discharge • Channel is wide and deep
108
Interlocking spurs meaning
When the river flows in a zigzag formation as it doesn’t have enough energy to erode hard rock
109
Discharge meaning
Amount of water in a river channel
110
Hydraulic action
When the flowing water is forced into cracks in the river bed/banks wearing them away
111
Attrition
When rocks carried by the river hit against each other chipping bits off so they become smaller rounder and smoother
112
Solution (erosion)
When acids in the water dissolve the face of the cliff (eg rocks like chalk and limestone)
113
Traction
When large heavy rocks are rolled along the river bed during a high discharge as there’s more energy
114
Saltation
When medium sized rocks bounce along the river bed
115
Suspension
When small light particles are lifted from the river bed and carried by the water (due to high discharge and velocity)
116
Solution (transportation)
When rock particles are carried as dissolved material
117
Where does the River Tees start
Cross Fell (Pennines) in North East England
118
Name of waterfall at River Tees
High Force
119
Estuary of River Tees
Middlesbrough where it meets the North Sea
120
4 erosion processes
• Hydraulic action • Abrasion • Attrition • Solution
121
4 transport processes
• Traction • Saltation • Suspension • Solution
122
Slip off slope characteristics
• A section of the river bank with a gentle gradient due to deposition
• Happens as the velocity of the river is low therefore it loses energy
123
Riffles and pools characteristics
• Deep and shallow areas of the river channel
• Formed by different sized deposited rocks on the river bed
• This causes the water to start spinning in a corkscrew motion (helicoidal flow)
124
River cliff characteristics
• Section of the river bank with a steep gradient due to lateral erosion
• This happens due to a high velocity (Thalweg)
125
How does a waterfall form?
• Hard resistant rock meets softer rock
• Water erodes the softer rock (abrasion and hydraulic action)
• Soft rock is undercut
• Hard rock becomes unsupported and collapses due to gravity
• Waterfall retreats leaving a gorge behind
126
Plunge pool
Area at the base of a waterfall that is eroded by abrasion and hydraulic action
127
How do floodplains form?
• Alluvium flows onto the land next to river as the river floods
• This causes friction and the sediment to be deposited in layers
• Therefore floodplains have a flat gradient
128
Alluvium
Sediment dropped on the floodplain
129
What is a levee?
Raised ridge of sediment either side of a river channel that are deposited when a river floods
130
How does a levee form?
[Define what a levee is]
• A river overflows due to high precipitation leading to an excessive discharge
• Friction with the floodplain leads to a rapid decrease in the velocity of the river and therefore its capacity to transport material
• Larger material is deposited closest to the river bank (as they need more energy for transport). This often leads to large, raised mounds being formed.
• Smaller material is deposited further away as they’re lighter to carry
• The rain eventually stops and discharge gets smaller
• This process repeats over a long period of time to create a sloped fertile floodplain of alluvium
131
Gorge meaning
A narrow valley with steep walls left behind as the waterfall retreats
132
What is a cross profile?
A slice taken across a river showing how wide and deep it is
133
What’s a meander?
A bend in the river
134
What’s an ox-bow lake?
A curved lake left behind when a meander becomes cut off from the main river channel
135
Why is the upper course of a river narrow?
A lot of friction takes place
136
Saturated meaning
When the ground cannot hold anymore water
137
Geology meaning
The type of rock a place is built on
138
Permeable meaning
Surfaces that allow water to pass through easily
139
Characteristics of Boscastle’s location
• South West of England
• North coast of the county Cornwall
• Confluence of the River Jordan and Valency
140
How does Boscastle’s physical factors affect flood risk?
• **The gradient of the valley is steep**
• This would encourage a high velocity due to gravity
• **The geology beneath Boscastle is impermeable slate**
• Therefore rainwater is unable to infiltrate
• **Boscastle is at the confluence of two rivers**
• Therefore the discharge would be higher
• **Prolonged heavy precipitation from a storm produced over 60mm of rainfall**
• The ground becomes saturated with water and the surface run off increases
141
How does Boscastle’s human factors affect flood risk?
• **A bridge was built over the river**
• Therefore debris carried by the flood got trapped preventing water flow
• **Trees above the valley were deforested**
• Therefore rainwater could not be intercepted and the discharge increases
• **Boscastle was built on the floodplain of a confluence**
• Therefore impermeable concrete surfaces increased surface runoff & water flowing into river
142
Possible economic impacts of river flooding
• Large repair costs as property and businesses get damaged
• Therefore people lose their source of income and support becomes required from insurance companies
• Tourists avoid visiting the area
• The tourism industry declines and people become unemployed so the rate decreases
143
Possible social impacts of river flooding
• Floods can contaminate water sources
• This increases the risk of waterborne diseases and decreases the life expectancy
• People become stranded on top of homes and buildings
• Therefore they are unable to escape the danger so helicopter rescues were relied upon
144
Possible environmental impacts of river flooding
• Trees get uprooted
• Therefore less leaves would be available to intercept the water in future and more precipitation reaches the ground
• The soil can become eroded
• Therefore the soil loses nutrients and becomes infertile so plants are unable to be grown
145
Sinuous meaning
Having many curves and bends
146
Soft engineering and its costs/benefits
Working with nature to prevent flooding / coastal erosion (and give example in exam)
Costs:
• Less effective
• Less durable/sustainable
Benefits:
• Cheaper
• Can provide recreational opportunities
• Aesthetically pleasing
147
Hard engineering and its costs/benefits
Working against nature using man-made materials to prevent river flooding/ coastal erosion (and give example in exam)
Costs:
• Very expensive
• Not aesthetically pleasing
Benefits:
• Very effective
• Durable
• Impermeable
148
Soft engineering flood management strategies
• Floodplain zoning
• Flood warnings
• Afforestation
• River restoration
149
How are flood warnings used to manage floods?
Involves alerting people to the risk of flooding (by The Environment Agency)
**Pros:**
• It gives people time to reinforce buildings which
• Reduces the impact of flooding
**Cons:**
• Doesn’t stop flooding
• Not all people will be aware
150
How is flood plain zoning used to manage floods?
It involves putting building restrictions on floodplains at risk of flooding
**Pros:**
• Businesses and houses aren’t damaged as they aren’t built on the floodplain
• Impermeable surfaces aren’t built on the floodplain
**Cons:**
• Difficult to implement on already developed floodplains
• Urbanisation becomes restricted
151
How is afforestation used to manage floods?
This involves planting trees to increase interception and lag time
**Pros:**
• Discharge in the river reduces
• Risk of soil erosion is reduced
**Cons:**
• Restricts what the land can be used for
152
How is river restoration used to manage floods?
It involves returning a river to its natural state (eg removing river straightening)
**Pros:**
• Cheap solution
• Discharge in the river reduces
**Cons:**
• Flood risks can increase if nothing else is done
153
Hard engineering flood management strategies
• Dams and reservoirs
• River straightening
• Embankments
• Flood relief channels
154
How are dams and reservoirs used to manage floods?
Concrete barriers are built across the river to control water flow
**Pros:**
• The water flowing through the dam can be used for hydroelectricity
• Reservoirs store a large volume of water reducing the risk of floods
**Cons:**
• Large areas of land are flooded
• Expensive to build
155
How are embankments used to manage floods?
The banks of a river are built up allowing a higher discharge before overflowing
**Pros:**
• More sustainable
• Looks more natural
**Cons:**
• Expensive to install
156
How is river straightening used to manage floods?
It involves cutting through meanders to create a straight channel
**Pros:**
• speeds up the flow of water so the risk of flooding decreases
• Water is taken out more quickly as the course is shortened
**Cons:**
• Increases flood risk downstream
• River banks are eroded faster
157
How are flood relief channels used to manage floods?
Man-made channel created to divert water around urban areas
**Pros:**
• River discharge decreases
**Cons:**
• Hard to find land to build relief channels
• Can be expensive
158
Soft engineering strategies used to manage the flash flood in Boscastle
• **The river channel was widened and deepened**
• This allowing a higher discharge
• **Dead trees were removed to prevent being swept away in future**
• This prevents debris blocking water flow
• **The car park was rebuilt using permeable material** (gravel)
• This allows water to infiltrate the ground
• **Land owners were encouraged to maintain vegetation and plant new trees**
• Therefore more water is intercepted
159
Hard engineering strategies used to manage the flash flood in Boscastle
• **Low bridges were replaced with higher wider bridges**
• This prevents debris from blocking water flow
• **The car park was raised to higher ground**
• So a higher discharge is required to affect them
160
Social impacts of Boscastle’s flood management scheme
• The residents’ lives were disrupted by rebuilding projects (-)
• New defences made Boscastle a safe place to live (+)
• Many residents do not like the new bridge (-)
161
Economic impacts of Boscastle’s flood management scheme
• Less risk of expensive damage to property/businesses (+)
• The scheme cost £10 million which is very expensive (-)
• Tourists have returned to Boscastle improving the local economy (+)
162
Environmental impacts of Boscastle’s flood management scheme
• Vegetation and river habitats are managed better which improves the biodiversity (+)
• Land owners planting more trees has provided a habitat for wildlife (+)
• The embankment isn’t attractive to look at (-)
163
What is a flood hydrograph?
Graph that shows how a river responds to a period of rainfall
[more on KU]
164
Peak discharge (hydrograph)
The point on a hydrograph where the river channel has the most water in it
165
Rising limb (hydrograph)
Shows the increasing flood water in the river
166
Recession limb (hydrograph)
Shows the decreasing flood water in the river
167
Lag time (hydrograph)
Time difference between the peak rainfall and the peak discharge
168
Base flow (hydrograph)
The normal amount of discharge you would expect in a river
169
Key features of a hydrograph
• Precipitation
• Time since rainfall
• Discharge
• Peak discharge
• Peak rainfall
• Rising limb
• Recession limb
• Lag time
• Base flow
170
[Coasts]
What are waves caused by?
Friction between the wind and the water
171
What is the top of a wave called?
Crest
172
What is the fetch of a wave?
The distance a wave travels
173
Characteristics of constructive waves
• They tend to build the beach
• They create wide flat beaches with a gentle slope
• They have a short height
• There’s a long wavelength
• Swash is stronger than backwash so deposition occurs
• Occur when there’s a long fetch
174
Characteristics of destructive waves
• Backwash is stronger than the swash therefore sediment is removed
• There’s a short wavelength
• They create narrow beaches with a steep slope
• They’re tall in height
• They tend to erode the coast
175
What is longshore drift?
Where sediment is transported along the coastline by the swash and backwash
176
How does a spit form? (5)
• A spit is formed by the movement of sediment carried by longshore drift
• The prevailing wind pushes constructive waves up the beach at an angle as the swash
• Then the backwash comes back down the beach at a ninety degree angle due to gravity
• Overtime, material zigzags along coast
• If the prevailing wind changes direction, the direction of longshore drift also changes which causes the spit to recede and form a hook
• A salt marsh also tends to form as deposition takes place and the waves slow down losing its energy
• The spit acts as a shelter from the oncoming waves
• Therefore, plants grow here and colonise the area.
177
Discordant coastline definition
When bands are at a right angle to the coastline (therefore headlands and bays form)
178
Concordant coastline definition
When bands of rock are parallel go the coastline (therefore it erodes at the same speed)
179
Differential erosion definition
When one type of rock erodes faster than another
180
How does a bar form?
• A spit extends out to sea due to sediment being carried by long shore drift
• It then joins 2 headlands together
• A freshwater lake (lagoon) forms behind it as its sheltered from sea waves
181
How does a tombolo form?
When a spit extends out to sea due to longshore drift and joins onto an island
182
Sand dunes are formed when
The wind deposits sediment
183
Sequence of the formation of a stump due to coastal erosion
• Crack
• Cave
• Arch
• Stack
• Stump
184
Soft engineering strategies that protect the coastline
• Beach replenishment
• Dune regeneration
• Dune fencing
• Managed retreat
185
Hard engineering strategies that protect the coastline
• Gabion cages
• Sea wall
• Rock armour (rip rap)
• Groynes
186
How do gabion cages protect the coastline?
• They’re wire cages filled with rocks that act as a buffer against the sea
• Energy from destructive waves is absorbed when water passes the gaps between rocks
187
Advantages and disadvantages of gabion cages
Advantages:
• Cheap to produce
• Improves drainage of the cliff
• Absorbs energy from destructive waves
Disadvantages:
• Unattractive to look at
• Cages only last 5 - 10 years before rusting
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How does a sea wall protect the coastline?
• The concrete rock barriers has a curved face to deflect the waves and cause the energy to dissipate
• Preventing erosion by abrasion/ hydraulic action
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Advantages and disadvantages of a sea wall
Advantages:
• Effective and often has a walkway to walk along
Disadvantages:
• Looks unnatural
• Expensive to maintain
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How does rock armour protect the coastline?
• Pieces of large boulders are dumped at the foot of a cliff
• It slows down the velocity of the waves as it absorbs and dissipates (spreads) the energy away from the land
• Preventing hydraulic action and abrasion from occurring
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Advantages and disadvantages of rock armour
Advantages:
• Cheap and easy to maintain
• Often used for fishing
Disadvantages:
• Can be expensive to transport the rocks
• Doesn’t fit with local geology
192
How do groynes protect the coastline?
• Resistant structure (eg timber) is built out to sea which helps trap sediment being moved by longshore drift
• This causes the beach to be built up overtime creating and buffer
• To prevent land from being eroded by abrasion/hydraulic action
193
Advantages and disadvantages of groynes
Advantages:
• Creates a wider beach which can attract tourists
• Useful for the fishing industry
• Acts as a buffer to sea
Disadvantages:
• Interrupts longshore drift which starves beaches further along the coast
• Leads to faster erosion
194
How does beach replenishment protect the coastline?
It involves adding sand to an existing beach to make it higher and wider
195
Advantages and disadvantages of beach replenishment
Advantages:
• Cheap
• Blends in with the beach
• Increases potential for tourism
Disadvantages:
• Needs constant maintenance
196
How does dune regeneration protect the coastline?
• Involves restoring or creating sand dunes to act as a barrier against the sea
• Marram grass can be planted to stabilise the dunes
197
Advantages and disadvantages of dune regeneration
Advantages:
• Maintains a natural environment
• Supports biodiversity
• Absorbs wave energy
Disadvantages:
• Takes time to plant
• Laws restricting their access isn’t always followed
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How does dune fencing protect the coastline?
Fences are put up to encourage new dune formation
199
Advantages and disadvantages of dune fencing
Advantages:
• Has minimal impact on nature
• Controls public access to protect ecosystems
Disadvantages:
• Not attractive to look at
• Regular maintenance needed
200
What is managed retreat?
• A deliberate policy allowing the sea to flood low value land
• It’s more sustainable than coastal defences
201
Advantages and disadvantages of managed retreat
Advantages:
• Costs nothing
• Creates a natural salt marsh forming a natural buffer to the sea
• Forms a valuable wildlife habitat
Disadvantages:
• Coastline is eroded
• Course of erosion may also reach valuable land
202
Mass movement definition
The downward movement or sliding of material under the influence of gravity
203
Scree definition
Piles of rock fragments that have broken off from a cliff
204
Discrete data definition
Data that can be grouped into categories
205
Continuous data definition
Data that is in a sequence
206
How does a wave cut platform form?
• Erosion happens at the base of a cliff
forming a wave-cut notch
• Overtime the notch is enlarged by abrasion and hydraulic power [explain]
• The notch makes the cliff unstable and it collapses overtime due to gravity
• The process repeats and cliff retreats inland
• As the cliff retreats, a sloped wave cut platform is left behind at the base of the cliff due to depositon
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What are the 3 types of weathering?
• Biological
• Chemical
• Mechanical
208
Definition and example of biological weathering
Definition
• Where plants and animals cause rocks to be broken up
Examples
• When plant roots grow in cracks in the rock causing it to break apart
• Animals like rabbits also burrow into the rock
209
Definition and example of chemical weathering
Definition
• Where rocks are eaten away as a result of a chemical reaction with rainwater
Example
• Rain absorbs co2 from the atmosphere and becomes acidic
• It then dissolves soft rock on cliff faces eg chalk
• This is known as carbonation
210
Definition and example of mechanical weathering
Definition
• Where rocks are broken up by physical processes (usually temperature changes)
Example
• Freeze thaw weathering
211
What is freeze thaw weathering?
• The process begins with water collecting in the crack of a rock
• At night, the water freezes due to a fall in temperature and the water expands making the crack wider
• During the day, the ice thaws as the temperature rises and therefore the water contracts going deeper into cracks
• Repeated expansion & contraction over time makes the rock crack further until it splits
212
What are the 2 types of mass movement?
• Sliding
• Slumping
213
Sliding characteristics
• Involves a straight slide plane
• Rocks fall as blocks in a straight line
• Gravity makes the rocks fall
• Caused by the 3 types of weathering
• The cliff retreats
214
Slumping characteristics
• Involves a curved slip plane
• Rocks are rotated backwards
• Gravity causes rocks to fall
• Rocks end up becoming small particles
• Caused by the 3 types of weathering
• Causes the cliff to retreat
215
How do caves, arches, stacks and stumps form? (6)
• The headland is made of hard resistant rock that protrudes into the sea
• Destructive waves attack the headland
• Their strong backwash forces air and water into the cracks in the rock (hydraulic action) breaking the rocks away
• The crack increases in size from continued hydraulic action and abrasion forming a cave [explain]
• The destructive waves continue to erode the rock and eventually break through the back of the cave forming an arch
• The top of the arch eventually collapses due to gravity and weathering on top which leaves a tall stack behind [explain example]
• The stack is eroded further at the base by destructive waves and eventually collapses to leave a stump
216
[Natural hazards]
What is a natural hazard?
An event caused by physical process that has a negative impact on people
217
What are the 3 types of natural hazards?
• Atmospheric hazards
• Geological hazards
• Hydrological hazards
218
What is an atmospheric hazard and some examples?
• Hazards driven by processes in the Earth’s atmosphere
• Eg Tornadoes
• Tropical storms
• Wildfires
219
What is a geological hazard and some examples?
• Hazards driven by processes happening inside the Earth
• Eg Earthquakes
• Volcanic eruptions
• Tsunamis
220
What is a hydrological hazard and some examples?
• Hazards driven by water bodies
• Eg Flooding
• Tsunami
221
Hazard risk meaning
The probability of being affected by a natural hazard event
222
What factors affect hazard risk in Japan?
• A **high population density** means more people are vulnerable
• This increases hazard risk
• Japans **geographical location** is where 3 tectonic plates meet therefore earthquakes are likely to occur
• Also Japan is prone to high intensity tropical storms
• This increases hazard risk
• **Climate change** has meant that temperatures in Japan are above average which creates conditions for hazards like drought
• Japan is a **HIC** which means that the country can afford to build expensive infrastructure to protect its population
223
How does Japan’s infrastructure make it more resistant to natural hazards?
• Earthquake resistant buildings are constructed with flexible materials allowing them to sway and absorb seismic waves
• Rubber shock absorbers underground also absorb seismic waves
• Tsunami walls have been built in coastal areas for protection against the strong waves
224
What are tsunamis caused by?
Earthquakes under the sea displacing water onto the land
225
Why did people live in areas with a high hazard risk?
• **Poverty** means that people have no choice because they can’t afford to live elsewhere eg LIC Haiti
• Some countries are **well prepared and protected** for naturals hazards eg Japan
• Steam from below the Earth’s crust in volcanic areas (as water in the lithosphere is heated) is used for **geothermal energy** eg New Zealand
• Volcanoes tend to come with **fertile soil** as minerals are brought up to the surface from underground eg Italy
• Hazardous landscapes can be attractive to visitors and increase **tourism**
226
What is a drought?
When a place experiences less rainfall than usual for an extended period of time
227
Volcanic eruptions are most prevalent..
Around the outside of the Pacific Ocean
228
What is geothermal energy?
Energy generated by stem being heated up within the Earth’s crust
229
What are the 4 layers of the Earth?
• Crust
• Mantle
• Outer Core
• Inner Core
230
Characteristics of the crust
• Very thin layer
• Made of solid rock
231
Characteristics of the mantle
• Made of semi molten rock
• Around 3000°C hot
• Thickest layer
• Where convection currents occur
232
Characteristics of the outer core
• Made of liquid iron
• 4500°C hot
233
Characteristics of the inner core
• Made of iron and nickel
• Hottest layer (5500°C)
234
Epicentre definition
Point on Earth’s surface above the focus where the earthquake is felt most strongly
235
Focus definition
The point within the crust where the earthquake starts
236
Fault definition
A fracture in the rock of the Earth’s crust
237
Seismic waves definition
Waves that are released during an earthquake
238
Tectonic plate definition
Sections of the Earth’s crust that come into contact with each other at a plate margin
239
In what direction do the plates move in a conservative plate margin?
➡️
⬅️
240
What happens at a conservative plate margin?
• Plates slide past each other and lock together
• This causes friction making pressure build up
• They suddenly snap loose which causes vibrations in the earth’s crust known as seismic waves
• Earthquakes occur on the surface
241
What kind of plate margins do earthquakes occur and why?
• Conservative plate margins
• Constructive plate margins
• Collision plate margins
• Destructive plate margins
Because friction is built up at each plate margin
242
What type of plate margin best shows how an earthquake happens?
Conservative plate margins
243
In what direction do the plates move in a constructive plate margin?
⬅️ ➡️
244
What happens at a constructive plate margin?
• Convection currents in the mantle cause the 2 continental plates to move apart
• This is where magma circulate as it gets heated by the core, the less dense magma rise and more dense sinks
•Magma rises through the gap due to pressure
• Gentle volcanic eruptions take place
245
What direction do the plates move in a collision plate margin?
➡️ ⬅️
246
What happens at a collision plate margin?
• The same type of plate move towards each other
• Since both plates are the same density, both are forced upwards to form fold mountains
• As the plates push into each other, friction builds up causing an earthquake
247
In what direction do the plates move in a destructive plate margin?
➡️ ⬅️
248
What happens at a destructive plate margin?
• A continental and oceanic plate move towards each other
• Since the oceanic plate is more dense it gets subducted
• As it sinks, it melts and makes magma in the subduction zone
• Therefore, heat & pressure build up under the crust
• Eventually, the hot magma is forced up through the cracks to form an explosive volcanic eruption
249
Ecosystem meaning
A natural system that includes all biotic and abiotic parts sharing an environment
250
How does a coastline of headlands and bays form and change over time?
• They’re formed by a discordant coastline made of bands of hard and soft rock perpendicular to the sea
• As the waves erode the coastline, the softer less resistant rock will be eroded quicker. This results in the areas of softer rock to retreat, forming bays
• The hard rock is eroded slower so will form headlands (differential erosion)
• Over time, deposition will occur in the bays as the majority of energy is directed towards the sticking out headlands
• This means the bays receive less energy and deposition therefore occurs forming a beach
251
Spit definition
A sand beach that is joined to the land but projects out into sea
252
Impacts of the Boscastle flood (2004)
• Homes and businesses belonging to more than 1000 people were destroyed
• Therefore insurance companies were relied upon to compensate for loss of income/shelter
• Tourists no longer wanted to visit the village
• The industry declines and people become unemployed so standard of living decreases
• Trees were uprooted and destroyed
• Less leaves are available in future to intercept rainfall
• Decreases biodiversity as animals lose habitat
253
Impacts of the Chile 2010 Earthquake (Primary and Secondary)
**Primary:**
• 220,000 homes were destroyed
• 4500 schools and 56 hospitals were destroyed
• 53 ports were destroyed
**Secondary:**
• The overall cost of damage is estimated at $30 billion
• Landslides destroyed up to 1500 km of roads, cutting off communities
• Power supplies were cut off for a month
254
Short term responses to Chile earthquake 2010
• Within 24 hours, the north south divide highway was temporarily repaired allowing aid to be transported
• Was essential as 220,000 homes so access to food was limited
• Food security is maintained and less diseases are contracted, reducing number of deaths
• 90% of homes had power and water restored within 10 days
• Was essential as power supplies cut off for a month
• Food can be refrigerated and cooked
which prevents food spoiling and improves quality of life
255
Long term responses to Chile earthquake 2010
• A housing reconstruction plan was launched to help nearly affected 200,000 families
• Was essential as 180,000 were made homeless
• People gain access to shelter which also means clean water access and sanitation, preventing diseases spreading so standard of living improves
• Recovery took over 4 years to fully reconstruct buildings and ports
• Was essential as 53 ports were destroyed
• This enables the flow of exports so that income is generated for economy and be spent on development eg education
256
What are the social impacts of climate change?
• Coastal erosion can occur due to rising sea levels
• Therefore properties get damaged and people are forced to evacuate
• Food shortages occur as droughts happens more often
• Vegetation growth decreases so people could be more likely to starve
257
Difference between food web and chain
Food webs have a number of connected food chains whilst food chains only have one straight chain
258
2 reasons nutrient cycling is rapid in tropical rainforests
• High humidity
• Fast growth of vegetation
