Coasts key terms

Question 1

Wavelength

Answer 1

The distance between two successive crests

Question 2

Wave frequency

Answer 2

Number of waves per minute

Question 3

Wave crest

Answer 3

Highest point of a wave

Question 4

Wave trough

Answer 4

Lowest point of a wave

Question 5

Wave steepness

Answer 5

The ratio of the wave height to the wavelength

Question 6

Wave period

Answer 6

The time taken for a wave to travel between one wavelength

Question 7

Wave energy

Answer 7

A product of wind velocity, duration and fetch

Question 8

Fetch

Answer 8

The distance the wind blows over the sea - the bigger fetch, the bigger wave

Question 9

Erosion

Answer 9

EROSION IS THE WEARING DOWN OF ROCK BY MOVING FORCES - usually occurs at the base of our cliffs and by waves.

Question 10

Weathering

Answer 10

WEATHERING IS THE WEARING DOWN OF ROCK ‘IN SITU’ BY ITS ENVIRONMENT - Sub aerial forces (like rain, air and temperature)

Question 11

Mass movement

Answer 11

MASS MOVEMENT IS THE MOVEMENT OF ROCK DOWNHILL UNDER GRAVITY

Question 12

Freeze thaw

Answer 12

Water repeatedly freezes and melts within rock joints in areas - as water freezes it expands and puts pressure on the rock, until it shatters

Question 13

Pressure release

Answer 13

Overlying soil or regolith is removed, this pressure release can open joints in underlying rock

Question 14

Biological weathering

Answer 14

Organic agents (trees, animals) grow and burrow into rock.

Question 15

Chemical weathering

Answer 15

Occurs where there is alternate wetting and drying of an area which leads to a chemical reaction or breakdown of the cliff face.

Question 16

Mechanical weathering

Answer 16

Takes place when rocks are broken down without any change in the chemical nature of the rocks

Question 17

Soil creep

Answer 17

Top soil moves downslope under gravity - Wet and thawing periods add moisture and weight which increases creep

Question 18

Solifluction

Answer 18

When an area begins to thaw, after a period of extended permafrost, the top soils can slide downslope as a whole layer

Question 19

Mudflows

Answer 19

Heavy rainfall saturates ground on steeper slopes and unconsolidated soils flow downslope

Question 20

Rockfalls

Answer 20

Rapid falling of rock/debris down very steep slopes or cliffs, rocks weakened by chemical weathering

Question 21

Runoff

Answer 21

Surface runoff has ability to move soil and debris down slope - Particularly vulnerable are areas with little vegetation.

Question 22

Slides and slumps

Answer 22

Slides and slumps maintain the structure of the strata of soil and rocks as they rotate and slip along weak fissures

Question 23

Hydraulic action

Answer 23

Erosion of the cliffs caused by the force of water and air in the waves colliding against them

Question 24

Abrasion

Answer 24

Erosion of the cliffs as waves throw particles and rocks against them.

Question 25

Attrition

Answer 25

Erosion of the material carried in the waves. The material in the waves is smoothed as it bumps into each other

Question 26

Solution (erosion)

Answer 26

Erosion of the cliffs by the salts and acids in seawater. Salts and acids are able to dissolve some rocks

Question 27

Solution (transportation)

Answer 27

Minerals are dissolved in the water and carried along in solution.

Question 28

Suspension

Answer 28

Fine light material is carried along in the water

Question 29

Saltation

Answer 29

Small pebbles and stones are bounced along the river bed

Question 30

Traction

Answer 30

Large boulders and rocks are rolled along the river bed

Question 31

Deposition

Answer 31

The dumping of sediment by the sea - occurs when the waves lose energy

Question 32

Offshore

Answer 32

Beyond the influence of the waves

Question 33

Nearshore

Answer 33

Where the friction with the seabed causes the waves to slow and begin to break

Question 34

Foreshore

Answer 34

The zone of constant change - swash and backwash operate here - Littoral drift occurs - Berms, ridges and runnels are created

Question 35

Backshore

Answer 35

Affected by the spring high tides that deposits larger calibre sediment here

Question 36

Eustatic sea level rise

Answer 36

Sea level change caused by change in volume due to ice caps melting

Question 37

Isostatic sea level rise:

Answer 37

Sea level change caused by change of weight as ice melts on land

Question 38

Postglacial rebound

Answer 38

Ice physically pushes land down (glacial subsidence)- when ice melts, the land bounces/rebounds back up

Question 39

Example of sea level rise case study

Answer 39

Tuvalu, Polynesian Islands

Question 40

Example of hard engineering shoreline management plan

Answer 40

Lyme Regis, Jurassic Coast

Question 41

Example of soft engineering shoreline management plan

Answer 41

North Norfolk

Question 42

Example of headlands and bays

Answer 42

Swanage Bay, Dorset | Discordant coast line

Question 43

Example of a cliff, wave cut notches and platforms

Answer 43

Burgh Island, Devon

Question 44

Example of Cracks, Caves, Arches, Stacks and Stumps

Answer 44

Old Harry rocks

Question 45

Example of a spit

Answer 45

Spurn Head, Holderness Coast

Question 46

Example of a bar

Answer 46

Slapton sands, Devon

Question 47

Example of a tombolo

Answer 47

Chesil Beach - connects the Isle of Portland to the mainland of the Dorset coast

Question 48

Formation of a wave

Answer 48

1) The wind blows over the sea 2) This creates ripples 3) These ripples become bigger swells 4) Swells approach land 5) The sea becomes shallower 6) The bottom of the wave slows due to friction 7) The top keeps going and forms a crest 8) The crest topples forming a breaking wave

Question 49

Two parts of a wave

Answer 49

- Swash: the movement of the wave up the beach | - Backwash: the movement of the wave back down the beach

Question 50

Characteristics of a constructive wave

Answer 50

- Created by short fetch - Small, gentle waves with low energy - Deposit sediment - Swash is stronger than the backwash.

Question 51

Characteristics of a destructive wave

Answer 51

- Created by large fetch - Big, strong waves with high energy - Erode the coastline - Backwash is stronger than the swash

Question 52

Spring tide:

Answer 52

When the moon is between the Earth and sun their combined gravitational pull creates the biggest bulge of water and the highest tide

Question 53

Neap tide:

Answer 53

When the Earth, moon and sun form a right angle their gravitational pull interferes with one another giving the lowest high tides and highest low tides - small tidal range.

Question 54

Tidal range:

Answer 54

The tidal range determines the vertical range of erosion and deposition and the length of time the littoral zone is exposed to subaerial weathering

Question 55

Tidal Bores

Answer 55

When water from an open stretch of ocean is confined in narrow sections of estuaries the tide is amplified