systems and processes

Question 1

how is wind a source of energy in a coastal system

Answer 1

wind is created by air moving from areas of high pressure to areas of low pressure

• strong winds generate powerful waves
• prevailing winds generate high energy waves

Question 2

how are waves a source of energy in a coastal system

Answer 2

waves are created by the wind blowing over the sea surface

-the effect a wave has on the shore depends on wave height and fetch (high windspeed and long fetch create powerful waves

Question 3

constructive waves characteristics

Answer 3

low frequency
low and long
powerful swash

Question 4

destructive waves characteristics

Answer 4

higher frequency
high and steep
strong backwash

Question 5

how do tides a source of energy in a coastal system

Answer 5

the periodic rise and fall of the ocean surface caused by the moon and suns gravitational pull

• tides affect the position at which waves break on the beach and therefore the extent of erosion on the beach
• the are between maximum high tide and minimum low tide

Question 6

how are currents a source of energy in a coastal system

Answer 6

currents are generated by the flow of water on one direction caused by wind or variations in water and salinity

rip currents: backwash is forced under the surface due to resistance from breaking waves , forming an underwater
current

-currents move material along the coast and can lead to output of sediment from the beach area

Question 7

high energy coasts 7 features with example

Answer 7

• high inputs of energy
• large powerful waves
• strong winds due to long fetch
• greater rate of erosion
• sandy coves
• steeply shelving offshore -zones
• rocky landforms- headlands, cliffs, wave cut platforms

-e.g. north cornish coast

Question 8

low energy coasts 6 features with example

Answer 8

• low inputs of energy
• gentle waves
• gentle winds
• greater rate of deposition
• gently sloping offshore zones
• landforms- saltmarshes, tidal mudflats, beaches, spits

-e.g. baltic sea

Question 9

5 sediment sources

Answer 9

• rivers; carry eroded material form inland
• sea level rise: floods form estuaries that become apart of coastal systems
• cliffs: sediment eroded, e.g. Holderness coast is eroding at 2m per year, one of the fastest eroding coastlines in Europe
• organic matter: crushed shells of marine animals
• waves, tides, currents: transport sediment

Question 10

define sediment budget

Answer 10

the difference between the amount of sediment that enters the system and the amount that leaves

a system will operate in a state of
dynamic equilibrium where input and outputs of sediment are equal.

However, human actions
and natural variation in the system can disrupt the state of equilibrium.

Question 11

define sediment cells

Answer 11

• Coasts can be split into sections called sediment cells which are often bordered by prominent
  headlands.

-Within these sections, the movement of sediment is almost contained and the flows
of sediment act in dynamic equilibrium.

-The dynamic equilibrium may be upset in the long term
by human interventions, or in the short term, they may be interrupted by natural variations.

• Within each sediment cell there are smaller subcells.
• 11 sediment cells in England

Question 12

what are 6 types of erosion

Answer 12

• corrasion/abrasion: rock and sediment grind against rocks and cliffs and breaks of rock smoothening the cliff
• hydraulic action: air in cracks is compressed when waves crash in. the pressure causes pieces to break off
• cavitation: as waves recede the compressed air expands violently again exerting pressure on the rock and causing pieces to break off
• wave quarrying: the energy of a wave as it breaks on a cliff detaches bits of rock
• solution/corrosion: soluble rocks dissolved in water
• attrition: bits of rock smash against each other in the water and break into smaller pieces

Question 13

what are 5 types of transportation

Answer 13

• solution: dissolved substances are carried along the water
• suspension: very fine material like silt is whipped up by turbulence and carried along the water
• saltation: larger particles like pebbles or gravel bounce along the river bed
• traction: very large particles like boulders are pushed along the sea bed

-long shore drift: swash carries sediment up the beach parallel to the prevailing wind
backwash carries it back down the beach at a right angle to the shoreline

Question 14

what are 3 types of mechanical sub-Arial weathering

Answer 14

• salt weathering: caused by saline water that enters cracks in rock at high tide. when the tide goes out the water evaporates and forms salt crystals which expand, exerting pressure on the rock causing pieces to fall off
• freeze thaw weathering: occurs in areas where temperature fluctuates around freezing. when water gets into rocks and freezes it expands weakening the rock and causing it to fall off
• wetting and drying: rocks that contain clay expand when they get wet and the pressure causes pieces to break off

Question 15

what are the 4 types of deposition: mass movement

Answer 15

• slides: material shifts in a straight line
• slumps: material shifts with a rotation
• rockfalls: material breaks up and falls
• mudflows: material flows downslope

Question 16

define sub-aerial weathering

Answer 16

the gradual breakdown of rock in situ by ice, plant roots and acid which weakens rocks and makes them vulnerable to erosion and alters the coastline

there are 3 main types:
biological
mechanical
chemical

Question 17

define mass movemnt

Answer 17

shifting of material down hill due to gravity caused by the undercutting of cliffs by wave action

Question 18

what is a spring tide

Answer 18

-Occurs when the highest high tide and the lowest low tides occur.

-the sun and the moon are in
alignment, so their gravitational forces work with each other.

-This creates
the largest possible tidal range

Question 19

what is the neap tide

Answer 19

Occurs when the lowest high tide and the highest low tides occur.

-the sun and the moon are
perpendicular to each other, so their gravitational forces work against each other.

-This creates the smallest possible tidal range.

Question 20

what is biological sub aerial weathering

Answer 20

this is breakdown of rocks by organic activity

when plants grow in between cracks of rocks and widen them

when animals burrow into rock for shelter

Question 21

what is chemical subaerial weathering

Answer 21

the decomposition of rocks by changing the minerals

Chemical weathering occurs as a result of a weak chemical reaction between water and rock