Coasts EQ2

Question 1

How are waves formed?

Answer 1

Friction between wind and surface water generates ripples, which grow into waves if wind is sustained

Question 2

What does wave size depend on? (4 factors)

Answer 2

-Strength of wind
-Duration the wind blows for
-Water depth
-Wave fetch

Question 3

What causes tides?

Answer 3

The gravitational pull of the Moon acting on Earth’s surface

Question 4

Amphidromic points (don’t need to know this but I’ve put it here anyways)

Answer 4

Locations on the coast where there is little variation between high and low tide

Question 5

Swell waves/Tidal bores

Answer 5

Local/sea waves that travel only short distances, created by local winds and storms

Question 6

How can tides affect coastal processes?

Answer 6

Spring tides at new/full moons can increase coastal flooding in some areas

Some locations have large tidal ranges

Question 7

Features of a constructive wave

Answer 7

-Low wave height (<1m)
-Long wave length (up to 100m)
-Strong swash, weak backwash

Question 8

Features of a destructive wave

Answer 8

-Wave height (>1m)
-Wave length about 20m
-Strong backwash, weaker swash
-Creates offshore ridge/bar

Question 9

How are waves affected by water depth?

Answer 9

As waves get closer to the shore, wave height increases and wavelength decrease because the orbital motion in waves becomes more concentrated

Question 10

The 4 processes of erosion

Answer 10

-Abrasion
-Attrition
-Hydraulic Action
-Corrosion

Question 11

Blowhole

Answer 11

An erosional landform created when a cave turns upwards and break through the flat cliff top

Question 12

Cave

Answer 12

An erosional landform created when joints/cracks/fissures in the rock are eroded through hydraulic action

Question 13

The 4 transportation processes

Answer 13

-Traction
-Saltation
-Suspension
-Solution

Question 14

Process of longshore drift

Answer 14

Waves approach beach at an angle from a direction similar to prevailing wind

Backwash carries material down the beach under gravity

Question 15

Gravity settling

Answer 15

The energy of transporting water becomes too low to move sediment, with large pieces of sediment being deposited first

Question 16

Flocculation

Answer 16

A depositional process where very small particles like clay clump together due to electrical/chemical attraction, and then become large enough to sink (usually occurs in salt marshes)

Question 17

The difference between a swash aligned and drift aligned beach

Answer 17

Swash aligned beach eg. Lulworth Cove have waves that break perpendicular to the shoreline

Drift aligned beaches have sediment that is transferred along the coast by longshore drift

Question 18

Spit

Answer 18

A long, narrow feature, made of sand/shingle, extending from the land into the sea

Question 19

How is a spit formed?

Answer 19

On drift aligned beaches, sand or shingle is transported by longshore drift, but if the coastline suddenly changes direction, sediment will begin to build up

Due to wave refraction, the spit ca. begin to curve, forming a recurved spit

Question 20

Barrier beach/bar

Answer 20

A beach/spit that extends across a bay to join two headlands eg. Loe Bar, Cornwall

Question 21

Cuspate foreland

Answer 21

A triangular shaped headland that extends out from the main coastline, formed when the coast is exposed to longshore drift from opposite directions

Question 22

Tombolo

Answer 22

A beach which has formed between a small island and mainland

Question 23

Sediment cell

Answer 23

The sourcing, transfer and deposition of sediment along a stretch of coastline

Question 24

Sediment budget

Answer 24

The amount of sediment available to the sediment cell

Question 25

When do negative feedback mechanisms occur at the coast?

Answer 25

-A major cliff collapse occurs -Major erosion of sand dunes/spit during a storm

Question 26

How can positive feedback cause disequilibrium at the coast?

Answer 26

-Human intervention eg. groynes -Global warming causing climate change and sea level rise

Question 27

Erosion

Answer 27

The breakdown of rock due to the action of an external force eg. wind,waves,ice

Question 28

Weathering

Answer 28

The breakdown of rock in situ (not requiring any movement)

Question 29

3 different weathering types

Answer 29

Mechanical Biological Chemical

Question 30

Freeze-thaw

Answer 30

Mechanical weathering where water expands 9% in volume when freezing, exerting a force in cracks and fissures

Question 31

Carbonation

Answer 31

The slow dissolution of limestone due to weak carbonic acid (pH 5.6) in rainfall

Question 32

Hydrolysis

Answer 32

The breakdown of minerals to form new clay minerals due to the effect of water and dissolved CO2

Question 33

What is the relationship between climate and weathering

Answer 33

High rainfall, high temp-> high biological, moderate chemical Low rainfall, high temp -> very little weathering High rainfall, low temp -> chemical and mechanical

Question 34

How does weathering contribute to coastal landscapes?

Answer 34

Weathering important for sediment production in sediment cells Weathering can influence rates of recession on coastlines

Question 35

The 5 types of mass movement

Answer 35

Rockfalls Topple Translational slide Rotational slide Flow

Question 36

Rotational slide

Answer 36

Huge masses of material slowly rotate downslope, often caused by water adding greater weight causing material to slump