SECTION C Flashcards

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1
Q

how do waves form

A

by wind blowing over the sea causing friction

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2
Q

how do tsunamis form

A

when earthquakes or volcanic eruptions shake the seabed

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3
Q

what are the two types of waves

A

destructive and constructive

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4
Q

when are constructive waves formed and how

A

summer and formed by storms often hundreds of kilometres away

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5
Q

when and how do destructive waves form

A

formed by local storms close to coast

winter

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6
Q

what are characteristics of constructive waves

A

create a gently sloping beach

low waves with wave crest far apart

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7
Q

what are characteristics of destructive waves

A

waves close together
little swash
high backwash
steep beach

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8
Q

what are the three types of weathering

A

mechanical, chemical, biological

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9
Q

an example of mechanical weathering is freeze thaw describe this process

A

where water collects in cracks in rock
at night, water freezes and expands making cracks larger
as temperature rises ice thaws and water seeps deeper into rock
repeated freezing and thawing makes rock fragments break off

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10
Q

what is mass movement and state the 4 types

A

it’s the downward movement of weathered material

  1. rockfall
  2. landslide
  3. mudflow
  4. rotational slip
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11
Q

what is solution

A

dissolving of soluble chemicals in rock eg limestone

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12
Q

what is corrasion

A

rock fragments picked up by the sea are thrown at the cliff. they scrape and wear away the rock

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13
Q

what is abrasion

A

the sandpapering effect of pebbles grinding over a rocky platform

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14
Q

what is attrition

A

rock fragments carried by the sea knock against each other becoming smaller/ more rounded

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15
Q

what is hydraulic action

A

the power of waves as they hit the cliff trapped air is forced inside cracks in the rock which eventually cause it to collapse

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16
Q

what are the four ways sediment is transported

A
  • solution
  • suspension
  • saltation
  • traction
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17
Q

how does longshore drift occur

A

- where waves approach ‘head on’ sediment moves up and down the beach
- where waves approach at an angle, sediment moves along the beach in a zig zag pattern

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18
Q

how are bays and headlands formed

A

: tougher resistant bands of rock are eroded to form headlands
:weaker rock erodes more easily to form bays
bays are sheltered, depositon occurs and a beach forms

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19
Q

describe the formation of a wave cut notch and how it turns into a wave cute platform

A

waves break against a cliff, erosion close to high tide line will form a wave cut notch. over time it deepens undercutting the cliff which eventually collapses. this process repeats and cliff fully collapses and retreats leaves behind a gently sloping rocky wave cut platform

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20
Q

describe the formation of caves, arches and stacks

A
  1. lines of weakness (eg joints) in resistant rock are vulnerable to erosion
  2. abrasion and hydraulic action widen the joint forming a cave.
  3. erosion may lead to two-back-to-back caves breaking through a headland to form an arch.
  4. the arch is enlarged by erosion and the roof is attacked by weathering processes and collapses
  5. this leaves an isolated stack
  6. the stack is eroded and collapses leaving a stump
21
Q

where are sandy beaches mainly found

A

beaches are deposits of sand and shingle mainly found in sheltered bays and created by constructive waves

22
Q

where are pebble beaches found

A

along high energy coasts where sand is washed away

23
Q

what is a spit

A

a long finger of sand or shingle jutting out into the sea

24
Q

how do bars form

A

bars form when longshore drift causes spits to grow across a bay

25
Q

describe the formation of a spit

A
  1. longshore drift transports sand along the coast
  2. change in the shape of the coast line
  3. spit grows from the land out into the sea
  4. spit exposed to changes in wind and wave direction cause it to curve
  5. saltmarsh forms in sheltered water behind the spit as river mud deposits build up
26
Q

what are the three ways to manage coasts

A
  • hard engineering
  • soft engineering
  • managed retreat
27
Q

list 4 examples of hard engineering strategies

A
  • sea walls
  • groynes
  • rock armour
  • gabions
28
Q

what is a sea wall state + and - of them

A

-concrete or rock barrier at the foot of cliffs or top of beach. curved to reflect waves out to sea
+ effective at stopping the sea
- can look obtrusive and unnatural, very expensive (£5000-£10,000 per metre)

29
Q

what are gryones state + and -

A

they are rock structures built at right angles to beach. traps sediment moved by longshore drift it enlarges the beach which reduces wave damage
+ wider beach good for tourism
-unnatural and unattractive

30
Q

what is rock armour state + and -

A

piles of large boulders at foot of cliff that absorb wave energy to protect the cliff
+ easy to maintain and relatively cheap (£200,000 per 100metres)
- expensive to transport rock

31
Q

what are gabions state + and -

A

they are wire cages that support a cliff and provides a buffer against the sea
+ cheap to produce (£50,000 per 100 metres) and can improve cliff drainage
- cages rust within 5-10years

32
Q

what are the 2 soft engineering strategies

A

beach nourishment and dune regeneration

33
Q

what is beach nourishment state + and -

A

where sand and shingle is dredged offshore and transported to the coast barge dumped on beach to make it wider
+ blends in with existing beach
- expensive

34
Q

what is dune regeneration give + and -

A

where marram is planted to stabilise dunes and help them develop, which makes them effective buffers to the sea
+ maintains a natural environment good for wildlife
- time consuming to plant grass and construct fencing

35
Q

what is a drainage basin

A

a drainage basin is the area of land drained by a river and its tributaries

36
Q

how are interlocking spurs created

A

a mountain eroded vertically creating a V-shaped valley it winds around areas of resistant rock to create interlocking spurs

37
Q

how are waterfalls formed

A

as a river flows downstream it crosses different rock type, more resistant rock eroded less easily than less resistant rocks forming steps in a rivers long profile which are waterfalls

38
Q

what is a gorge and how are they formed

A

a gorge is a narrow, steep sided valley found downstream of retreating waterfall
formed at the end of at The end of the last glacial period masses of water for melting glaciers poured upland areas forming gorges

39
Q

what is the name of the fastest current in a river

A

thalweg

40
Q

what are meanders

A

they are bends in a river found mainly in lowland areas, they constantly change shape and position

41
Q

how are ox bow lakes formed

A

as meanders migrate across the valley floor erode towards each other which eventually forms ox-bow lakes

42
Q

what is a flood plain

A

they are wide flat areas on either side of a river and its middle and lower course they are created by migrating meanders and floods depositing layers of silt

43
Q

how are levees formed

A

they form in low flow deposition rises the riverbed so the channel can’t carry as much water during flooding water flows over the size of the channel as velocity decreases coarser sediment is deposited first on the bags then finer sand and mud raising the height of the levees

44
Q

what are estuaries how are they formed

A

Anniversary as where the River meets the Sea their affected by tidal wave action and river processes as the tide rises Rivers current flow into the sea so velocity fours and sediment is deposited forming mudflats which develop into salt marshes

45
Q

state 3 physical factors that cause flooding

A

PRECIPITATION- torrential rain storms or prolonged period of rain can lead to flooding
GEOLOGY - impermeable rocks don’t allow water to pass through flows over land into river channels
RELIEF - steep slopes mean water flows quickly into rivers

46
Q

what are the three human factors that cause flooding

A

URBANISATION-impermeable surfaces e.g. tarmac mains water flows into drain Susan river channels
DEFORESTATION-when trees are removed much of the water which has been evaporated from leaves or stored on leaves and branches flows rapidly into river channel
AGRICULTURE-expose soil can lead to increased surface run-off

47
Q

what are the four hard engineering processes to manage floods

A

dams and reservoirs
Channel straightening
embankments
flood relief channels

48
Q

what are the four soft engineering practices to reduce floods

A

Afforestation (planting trees)
 flood storage flood areas
floodplain zoning
River restoration