Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Geography - Physical - Paper 1 > Coasts - EQ3 - How do coastal erosion & sealevel change alter the physical characteristics of coastlines & increase risks? > Flashcards

Coasts - EQ3 - How do coastal erosion & sealevel change alter the physical characteristics of coastlines & increase risks? Flashcards

You may prefer our related Brainscape-certified flashcards:
U.S. Geography flashcards World Geography flashcards
1
Q

Define sea level

A

the level of the sea’s surface

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is sea level used to understand & measure

A

the height of geographical features in close proximity to it e.g hills

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is sea level determined by

A
  • the height of the surrounding water above sea level
    or
  • the atmospheric pressure at that level (below surface level)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

In what 2 ways can sea level trends & activity be measured

A

technology & models

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Explain a way in which sea level trends & activity be measured
Technology

A
  • tide & water level monitoring stations are computerized & fitted with sensors
  • that continually record both sea levels
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Explain a way in which sea level trends & activity can be measured
Model

A

earth’s gravitational model - used to work out sea level in areas that are not obvious

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Sea level change plays an important role in shaping (1)________ and (2)____________________both on global and local scale act to create (3)___________.

A
  1. coastlines
  2. fluctuations in sea levels
  3. a variety of coastal landforms
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Why can changes in the mean sea level often be complex

A
  • Sea level changes can be due to a change in the level of the sea or land,
  • either upwards & downwards
  • Sometimes, it can be both land and sea movements
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

cause or causes of a change in mean sea level are often ________

A

complex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the 4 causes of sea level changes

A

eustatic change
isostatic change
tectonic activity
climate change

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

how are coastlines influenced by sea levels

A

accretion - extended
post glacial adjustment - increased
submergence
emergence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

on what timescales do sea levels rise

A

long term
contemporary (short term/modern)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Why is it difficult to measure sea level

A

sea level fluctuates greatly throughout time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

how do sea levels fluctuate on the microscale

A

sea level changes according to the tide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

how do sea levels fluctuate on the macroscale

A

caused by ice ages or other major global events & are harder to monitor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How does climate change impact the difficulty of measuring sea level rises

A

it can be unclear whether the sea level rise is down to being in an interglacial period or due to climate change

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

define eustatic

A

global scale sea level change caused by a change in the volume of water in the ocean store

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

define isostatic

A
  • local scale sea level change
  • caused by a change in the level of the land relative to the level of the sea
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

define emergence

A

the impact of a relative fall in sea level (marine segression)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

define submergence

A

the impact of a relative rise in sea level

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

define accretion

A
  • Occurs when sediment is added to a landform, enlarging it by deposition, such as a river delta
  • It can build up to form new land, allowing a delta to grow out to sea
  • It tends to be balanced by subsidence (sinking), caused by the weight of the newly deposited sediment
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

define post glacial adjustment

A

the uplift experienced by land following the removal of the weight of ice sheets

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what are the 2 groups under which sea level rise can be classified

A

isostatic (local)
eustatic (global)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what are the 2 eustatic causes of sea level rise

A

melting ice
thermal expansion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Eustatic Change
refers to the change in…

A

sea level (up or down)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Explain how melting ice leads to fluctuations in sea level

A
  • During an ice age, much of the world’s water is stored as ice sheets, ice caps, glaciers and frozen ground.
  • Consequently, sea levels fall,
  • which is why during the last ice age there was no North Sea and the UK was still joined to the rest of Europe.
  • As the climate warms up the ice on the land melts and returns water to the sea.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

It’s estimated that sea levels have risen about ………….m since the end of the last ice age 10,000 years ago.

A

12,000

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is critical to remember regarding eustatic melting ice changes to sea level

A
  • melting sea ice does not count in this change as it already displaces its volume
  • Artic - water already displaced
  • Antarctica - underneath ice is land
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is one of the primary causes of sea levels rising

A

thermal expansion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Explain the process of thermal expansion

A
  • The earth is getting warmer primarily due to the accumulation of heat trapping greenhouse gases
  • 90% of which are absorbed by the oceans.
  • As the water’s temperature rises, the volume of oceans expands
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Thermal expansion has been occuring at a _____rate for decades & accounts for ___% of the sea level rise that occurred over the course of the 1900s

A

steady
75%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

what are the 2 isostatic causes of sea level rise

A
  • subsidence/ post glacial adjustment
  • accretion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

isostatic change occurs ……

A

locally

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Describe the process isostatic subsidence

A
  • During glacial periods & ice is km thick
  • it’s very heavy & able to push the land downward because the upper mantle underneath the crust is soft.
  • The sinking of the land is isostatic subsidence.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Describe how postglacial adjustment happens after isostatic subsidence

A
  • During glacial periods, the weight of the ice depresses the crust in areas below the ice sheets.
  • The rigid nature of the solid crust means that when sections of the crust are depressed by ice and forced down, adjacent areas are uplifted in a see-saw effect.
  • The melting of ice causes previously ice-covered crust to slowly rebound upwards whilst adjacent areas subside.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Give an example of isostatic subsidence

A
  • In the Uk, Scotland was pushed down by the weight of ice,
  • while Southern England rose slightly.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What is isostatic recovery

A
  • When ice sheets melt at the end of an ice age, the land that had been pushed down rebounds,
  • while the land that has been tilted upwards slightly starts to sink,
  • which is called isostatic recovery
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Scotland is in isostatic …………..

A

recovery

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

It takes …………. of years to transition from isostatic recovery

A

thousands

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Accretion
occurs when….

A

sediment is added to a landform, such as a river delta, by deposition

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Accretion
sediment can build up to….

A

form new land, allowing a delta to grow out to sea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Accretion
it tends to be balanced by…

A

subsidence (sinking), caused by the weight of the newly deposited sediment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

how can tectonics cause changes in sea level

A

can cause land to rise up out of the ocean, or sink (subside) into it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Tectonic plates on average move at about ….. per year

A

1-2 cm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

Tectonic plates moving about 1-2 cm per year will alter…

A

landform relativity to the sea level

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

define destructive plate margins

A
  • formed where an oceanic plate bounday meets a continental plate boundary
  • and undergoes subduction due to the greater density of oceanic crust,
  • causing sea levels to rise, possibly forming land forms
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

define constructive plate margins

A

plates being pulled apart, creating passive margins, causing sea levels to drop, creating landforms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

Explain an example of how tectonics can cause changes in sea level
New Zealand

A
  • Turakirae Head, Wellington, New Zealand
  • successive major earthquakes in the area have repeatedly lifted the shoreline by several metres
  • this has occurred 5 times during the last 7000 years
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

Explain an example of how tectonics can cause changes in sea level
Indonesia

A
  • The earthquake that caused the 2004 Boxing Day Tsunami in the Indian Ocean that killed nearly 300,000 people
  • the Indonesian island of Sumatra was worse hit
  • the earthquake caused the Earth’s crust at Banda Aceh to sink permanently by 4m
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

Describe the location of Kiribati

A

Consists of 33 widely spaced islands, which stretch across an area of the Pacific Ocean nearly as wide as the USA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

Kiribati is only ……. above sea level in most places

A

1 metre

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

What are sea levels expected to rise by in Kiribati

A

by around 40cm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

How has the Kiribati government secured food security in the future

A

agriculture & fish farming projects on land purchased by the government in Fiji

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

In Kiribati their crops are being…

A

contaminated by sea water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

What policy has the government launched in Kiribati

A

‘migration with dignity’

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

What is ‘migration with dignity’

A
  • Policy aiding the application for jobs in neighbouring countries for citizens of Kiribati
  • e.g New Zealand, as there is a reluctance to migrate from Indigenous tribes who take pride in their homeland, which is soon to be submerged
57
Q

What are emergent coastlines the consequence of

A

isostatic rebound

58
Q

Describe the isostatic uplift of a specific emergent coastline

A

In Scandinavia, isostatic uplift is at a rate of 2cm per year

59
Q

What creates emergent coastlines

A

a fall in sea level exposes land previously covered by the sea

60
Q

What are submergent coastlines the consequence of

A

sea level rise or eustatic changes

61
Q

Describe the submergence of a specific submergent coastline

A

In the UK, Land’s end is sinking at a rate of 1.1mm a year

62
Q

What creates drowned landforms

A

Eustatic rise since the end of the last ice age

63
Q

Name 2 emergent coastal landforms

A

Raised Beaches
Fossil Cliffs

64
Q

What is a raised beach

A

A landform that was once a beach, but now lies considerably above sea level

65
Q

What factors affect the formation of raised beach

A
  • tectonic activity
  • climatic conditions - can affect changes in sea level
66
Q

What is a fossil cliff

A
  • a steep slope found at the back of a raised beach,
  • exhibiting evidence of formation through marine erosion,
  • but now lies above high tide level
67
Q

What may fossil cliffs contain, providing evidence of formation by marine erosion

A

wave cut notches, caves & arches

68
Q

Give a location example for both raised beaches & fossil cliffs

A
  • Tay Valleys, in Eastern Scotland,
  • sea levels are fallling by 1.8 - 2mm annually
69
Q

Name 3 submergent coastal landforms

A

Rias
Fjords
Dalmatian Coasts

70
Q

What is a ria

A

a drained river valley

71
Q

How do rias form

A

as sea levels rise, they flood river valleys, leaving only high land visible

72
Q

________ are the most common coastal landform

A

Rias

73
Q

Where are Rias commonly formed

A
  • in periglacial areas that were adjacent to land covered by ice during the Devensian (last glacial period)
  • e.g Southern England
74
Q

Give a location example of a ria

A

South West England, Plymouth sound

75
Q

What is a fjord

A

a drowned glacial valley

76
Q

how do fjords form

A

as sea levels rise, U-shaped valleys left behind by glaciers are submerged

77
Q

Characteristics of fjords

A
  • steep valley sides
  • that are straight & narrow
78
Q

What is the difference between fjords & rias

A

Unlike Rias, fjords are much deeper in land than they are at the coast

79
Q

Give a location example of a fjord

A

Milford Sound, in New Zealand

80
Q

What is a dalmatian coast

A
  • composed of long narrow islands running parallel to the coastline
  • & separated from the coast by narrow sea channels called sounds
81
Q

how are dalmatian coasts formed

A

sea level rise flooding the coastline with the geographical structure of folds aligned parallel to the coast

82
Q

Give a location example of a Dalmatian Coast

A

The Dalmatian coast in Croatia

83
Q

Define anthropogenic

A

(chiefly of pollution or environmental change) originating in human activity.

84
Q

How can climate change cause sea level rise

A
  • Anthropogenic activity
  • causes increased global ocean temperatures
  • oceans experience thermal expansion
85
Q

Give evidence of the correlation between sea level rise & global temperatures

A
  • 0.85 degrees celsius increase in global temps from 1880 to 2012 coincided with a sea level rise of 21cm from 1870-2010
86
Q

What are the 2 reasons for sea levels rising from climate change

A

main reason - thermal expansion
secondary reason - melting of land ice in Polar regions & glaciers

87
Q

Scientists estimate that by 2100, average sea levels will have risen by ….

A

30cm-1m

88
Q

What are the four factors which result in coastal retreat

A
  1. geology/lithology
  2. marine processes
  3. subaerial processes
  4. human factors
89
Q

Characteristics of locations with slower rates of recession
lithology

A

resistant consolidated rocks

90
Q

Characteristics of locations with slower rates of recession
wave type

A

small constructive waves

91
Q

Characteristics of locations with slower rates of recession
mass movement

A

small scale

92
Q

Characteristics of locations with slower rates of recession
coastline

A

emergent

93
Q

Characteristics of locations with slower rates of recession
patterns of weathering

A

occasional or slow

94
Q

Characteristics of locations with rapid rates of recession
lithology

A

weakly consolidated rock

95
Q

Characteristics of locations with slower rates of recession
wave type

A

large destructive waves

96
Q

Characteristics of locations with slower rates of recession
coastline

A

submergent

97
Q

Characteristics of locations with slower rates of recession
mass movement

A

large

98
Q

Characteristics of locations with slower rates of recession
pattern of weathering

A

constant

99
Q

Name 4 ways in which humans causes coastal retreat/ recession

A
  • coastal defences
  • offshore dredging
  • anthropogenic climate change
  • people building on unstable cliffs
100
Q

How do coastal defences cause coastal retreat/recession

A
  • Coastal defences in one location might slow erosion,
  • but they also stop or reduce the amount of sediment available, in another part of the cell,
  • which could limit the amount of sediment for beach building
101
Q

As a result of coastal defences limiting the amount of sediment for beach building, when the beach gets….

A

narrower, it is less able to absorb wave energy & waves hit the backshore with more force

102
Q

what is offshore dredging

A

removing sand & gravel for construction, beach nourishment & deepening of port entrances

103
Q

How does offshore dredging, specifically the removal of sediment, cause coastal retreat/recession

A
  • sediment would originally have reduced wave energy before they hit the coast,
  • now the waves are not slowed,
  • & the full force hits the cliff
104
Q

How does offshore dredging, specifically the deepening of ports, cause coastal retreat/recession

A
  • deeper water caused by dredging may also allow waves to maintain their circular motion
  • & energy closer inshore
  • & become more destructive
105
Q

what is a delta

A

wetlands that form as rivers empty their water & sediment into another body of water, such as an ocean, lake or another river

106
Q

How does a delta form

A
  • a river moves more slowly as it nears its mouth or end
  • this causes sediment, solid material carried downstream by currents to fall to the river bottom
  • as silt builds up, new land is formed - this is the delta
107
Q

A delta extends a river’s ….

A

mouth into the body of water into which it is emptying

108
Q

What are the factors which contribute to retreat along the 240km coast of the Nile Delta

A
  • holiday beach resorts
  • fisheries
  • land reclamation
  • agriculture
  • settlements
  • transport & port infrastructure
  • general tourism
  • marine recreation
  • coastal defences
109
Q

Because the Nile Delta is retreating, it is estimated that …..% of Delta land area will be lost, with significant erosion to ……. of it

A

3.3&
half

110
Q

Name 4 impacts of sea level rise along the Nile Delta

A
  • salt intrusion into the delta’s fresh water
  • more frequent coastal flooding
  • 2 million hectares of fertile land will be lost
  • 6 million people displaced
111
Q

How is coastal recession being combatted along the Nile Delta

A

The UNDP have created an integrated coastal zone management plan, to ensure “environmental stability” - by creating a manmade delta

112
Q

How does anthropogenic climate change cause coastal retreat/recession

A

increasing storm energy & frequency, so waves have more energy to erode coasts

113
Q

How does people building on unstable cliffs cause coastal retreat/recession

A

the weight of buildings can increase the risk of mass movement & slumping

114
Q

Name the 6 factors which cause coastal flooding

A
  • removing vegetation/deforestation
  • subsidence e.g post glacial adjustment
  • sea level rise
  • increased frequency & magnitude of tropical storms
  • low altitude e.g Dutch
  • storm surges
115
Q

reasons why Bangladesh is vulnerable to coastal flooding

A
  • densely populated with 46% of the population lives less than 10m above sea level
  • large coastline - 580km
  • 3 rivers converge in Bangladesh
  • tropical monsoon climate
116
Q

What features of Bangladesh’s climate make it vulnerable to coastal flooding

A
  • Tropical monsoon climate
  • leads to floods & cyclones - storm surges
  • himalayan snow melt + monsoon rains + high tides
117
Q

Bangladesh is located within the ……. so has a high risk of ……..

A

tropics
cyclones

118
Q

Bangladesh lies on the…

A

floodplain of 3 major rivers (Brahmaputra, Meghna & Ganges) which converge there

119
Q

Describe Bangladesh’s population density

A

densely populated with 46% of the population lives less than 10m above sea level

120
Q

name 3 human actions which can increase the risk of coastal flooding

A
  • local subsidence
  • local vegetation removal
  • global sea level rise due to climate change (eustatic change)
121
Q

How is human induced subsidence increasing flood risk in Bangladesh
-embankments

A
  • embankments, which were poorly constructed in the 1960s
  • by deposited sediments, that can be easily infiltrated by water,
  • which result in poor drainage and low land elevation
122
Q

How is human induced subsidence increasing flood risk in Bangladesh
-vegetation

A
  • the clearance & drainage of more than 50 large island’s worth of vegetation increases flood risk,
  • & is then worsened by improper land use
123
Q

The Sundarbans Mangrove forest is one of the ……… forests in the world, ………. hecatres

A

largest
140,000

124
Q

describe the ongoing ecological processes in the Sundarbans Mangrove forest

A

this site is intersected by a complex network of tidal waterways, mudflats & small islands of salt tolerant mangrove forests

125
Q

What do mangroves provide, which decrease the risk of coastal flooding

A
  • absorb coastal water
  • reduces wave height by 13-66%
  • roots bind sediment together stabilising the coast
  • large carbon store (indirect)
  • ecosystems & shelter (to wide range of fauna eg Bengal tiger)
  • natural sea defence/barrier
126
Q

The suburban forest helped to take the sting out of ……… Isla in 2009

A

cyclone

127
Q

Recent studies show that ….% of Bangladesh’s mangrove coastline is retreating by as much as ……m per year

A

71%
200m

128
Q

How has the conversion of land led to the destruction mangroves, and subsequently sea levels rising

A

forests have been converted into lucrative shrimp farms, which accounts for 25% of this loss

129
Q

Sea levels are expected to rise ………. due to climate change

A

eustatically

130
Q

Bangladesh in expected to sink …………because of the loading of sediment on the delta

A

isostatically

131
Q

What are the social impacts of global sea level rise in Bangladesh

A

-mental health trauma
-houses destroyed
-unemployment (farming jobs lost)
-migration
-food insecurity
-diseases
-17 million people affected by 22,000m of land lost

132
Q

What are the environmental impacts of global sea level rise in Bangladesh

A
  • ecosystems damaged
  • salt water contaminating freshwater, killing the fauna as there are few halophytes
  • coastal cities such as Chittagong face inundation & ever greater threat from cyclones
133
Q

What are the economic impacts of global sea level rise in Bangladesh

A
  • 75% of agricultural land lost
  • cannot export food
  • major fishing villages will be affected agricultural land
  • and rice paddies will suffer the effects of salinization
134
Q

What were the social impacts of Cyclone Sidr in 2007

A
  • ports were blocked
  • wounds & injuries
  • 3363 dead
  • inaccessibility to resources
135
Q

What were the economic impacts of Cyclone Sidr in 2007

A
  • infrastructure e.g roads lost
  • $1.7 billion in monetary damages
  • farmland & businesses lost
136
Q

What were the environmental impacts of Cyclone Sidr in 2007

A
  • trees uprooted –> soil erosion
  • 1.87 million livestock dead
  • habitats destroyed
  • water pollution
137
Q

What were the social impacts of the North Sea Surge 2013

A

-40,000 homes lost power
-45 commercial properties were flooded
-7 homes fell into the sea

138
Q

What were the environmental impacts of Cyclone Sidr in 2007

A
  • 140,000 acres flooded
  • erosion of coastal dunes
  • the reactivation of a barrier island
  • notching of soft rock cliffs & coastline retreat of barrier island washed over deposits
139
Q

What were the economic impacts of Cyclone Sidr in 2007

A

£1billion in damage
rail services in Scotland cancelled

Geography - Physical - Paper 1 (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions