coasts Flashcards
most likely cause of destructive waves
a long fetch across Atlantic Ocean
how do you know longshore drift is from south to north
sediment accumulates on southern side suggesting that it arrives moving northwards
define mass movement
downhill movement of material due to gravity
name one type of coastal landform created by deposition
bar / spit / beach / tombolo
name one type of coastal landform created by deposition
bar / spit / beach / tombolo
what’s the sticking out thing on the beach called
headland
name and describe one process of coastal erosion
hydraulic action - force of water breaks off loose material
abrasion - pebbles are knocked into the coastline chipping off sections of rock
solution - chemicals and salt in the water dissolve surrounding rocks
name and describe one process of coastal erosion
hydraulic action - force of water breaks off loose material
abrasion - pebbles are knocked into the coastline chipping off sections of rock
solution - chemicals and salt in the water dissolve surrounding rocks
describe process of longshore drift
- longshore drift is the movement of beach materials along a coastline.
- the direction of longshore drift reflects the direction of the wind
- swash pushes pebbles up the beach
- while backwash pulls material down the beach
describe how cliffs collapsed
cliff could have been affected by erosion
hydraulic action could have weakened the bottom of the cliff creating an unstable overhang
explain how a stack will change in the future
stack will collapse to form a stump - abrasion will weaken the base of the stack
explain how a cave will change in the future
cave will be enlarged by erosion - pebbles from the beach will be picked up and smashed into the cave walls - turning it into an arc
how will a cliff change in the future
cliff will retreat - waves will hit the cliff forming a notch - the notch will grow larger until the cliff above collapses due to a lack of support
describe how groynes affect longshore drift
long shore drift is the movement of sand along a coastline - the eaves swash and backwash drag material along a beach - building groynes creates a barrier stopping the sand moving further - as there is less long-shore drift beaches down drift will become smaller
outline how rock armour works
absorbs the waves energy - slows down speed of wave - causes waves energy to dissipate - protects sea wall
how does sea wall work
acts like a barrier - absorbs power of waves - reflects the waves energy back to sea
describe how a wave cut platform is formed
cliffs are eroded - so they retreat - leaving a platform - which will be further eroded and weathered
explain one reason why there may be an increase in storm frequency in future
climate change increase storminess - larger areas of warm water generating more energy - more hurricanes
explain difference between concordant and discordant coastlines
headlands and bays - discordant - varied rate of erosion because of different types of rocks
rock parallel to coastline - concordant - more uniform
explain why there is an increasing risk of coastal flooding on many UK coastlines
climate change - caused by increasing levels of greenhouse gases - with human enhanced emissions - causing sea level rise - increased storminess - increase rates of erosion because of higher seas and more energetic wave attack
explain why differences in rock type affect the rate of erosion on UK coastlines
differences in rock hardness - which effects the rate of erosion through abrasion because softer rocks are less resistant
differences in rock structure - affected by hydraulic action/abrasion - well-jointed rocks erode faster than less well-joined rocks because larger surface area
one disadvantage of groynes
traps beach sediment - beaches further along the coastline will be starved of sediment / become narrower
groynes involve construction and wooden ones will rot - expensive to build and replace
explain one way rock type leads to the formation of headlands
more resistant rock type - will erode slower
explain now way in which destructive waves can increase the rate of coastal erosion
destructive waves formed by local storms - have more energy to erode beach - stronger backwash - remove more beach material
explain how one human activity increases chance of coastal flooding
human activities eg. burning fossil fuels - enhanced greenhouse effect - seal levels rise
more urbanisation - more impermeable surfaces
explain one way rip rap helps protect coastal landscape
large boulders are places along the cliff line - which protect the coast by acting by as a sea wall
explain why some waves erode more than others
larger fetch - destructive waves - stronger backwash
explain why some waves erode more than others
larger fetch - destructive waves - stronger backwash
explain formation of a bay
formed as a result of discordant coastline - bands of rock of alternating resistance - softer rock is eroded faster forming a bay - harder and softer rock eg. sandstone and clay
describe how swash and backwash can lead to a spit
- swash moves material up the beach at an angle
- backwash takes material off the beach at 90 degrees
- net movement of material along the beach
- spit grows when coastline direction changes
outline the reasons some cliffs retreat faster than others
rock type - some rock is softer
waves are more powerful - because of fetch or frequency of storms
economic consequence of coastal erosion
financial losses through costs of coastal protection schemes or insurance property or loss of property
