8 - variations of coastal processes over timescales

Question 1

what is a storm surge

Answer 1

result of extreme meteorological conditions and the configuration of coastline

water levels rise higher than predicted at high tide

can result in property damage and death

Question 2

what is the most recent disastrous storm surge in england

Answer 2

in 2013 , december 5-7, North Sea Storm Surge

intense rain, stormy seas, spring tide, low pressure system and low lying coastline and shallow sea lead to high storm surge

Question 3

what strong relationship can be seen regarding waves and the beach

Answer 3

WAVES (particularly steepness) and ANGLE of the beach

steepness = ratio from height to length. higher the value, greater energy brought to beach

Question 4

differences between winter and summer beaches

Answer 4

WINTER - waves have more energy due to stronger depressions. erode and transport material off beach and out to sea in powerful backwash. lower beach profile and less mass

SUMMER - waves have less energy - increased anticyclonic activity. deposit material in swash so built up profile. some beaches sandy in summer rocky in winter

Question 5

how can tides influence beach profiles

Answer 5

(LUNAR monthly cycle - spring high tide, neap high tide, neap low tide and spring low tide)

4 marks are made during the cycle

Question 6

how can seasonal variations influence beach profile

Answer 6

areas of monsoon activity or seasonal rainfall patterns

wet or dry seasons impact beach profile

Question 7

how does beach steepness influence other factors

Answer 7

steepness changes seasonally - type of beach may change

STEEP beaches have plunging waves - REFLECTIVE beach

SHALLOW beaches have breaking/spilling waves - DISSIPATIVE beach

Question 8

what are two main causes of long term change

Answer 8

EUSTATIC

ISOSTATIC

Question 9

what is eustatic changes

Answer 9

EUSTATIC = changes in absolute global sea levels, all seas/oceans interconnected

2 main causes:

• thermal expansion (warmer water expands with global warming)
• glacio-eustatic changes (melting ice caps/sheets release water locked up for long)

Question 10

what are isostatic changes

Answer 10

ISOSTATIC - regional changes of sea level

earths crust (lithosphere) floating on asthenosphere below

isostatic balance changed by increase/decrease in relative weight or changing meeting point of land and sea

Question 11

what is ISOSTATIC readjustment/rebound

Answer 11

in ice age, weight of glacier depressing land and sea levels raised

ice melts = land ‘rebounds’ slowly to original position increasing height relative to sea

still occurs in NW britain today, land rebounding since pleistocene epoch

Question 12

what is isostasy

Answer 12

GLACIO-ISOSTASY = occurs when weight of glaciers depresses land relative to sea

HYDRO-ISOSTASY = increased weight of water depresses ocean basins relative to land

fall in sea level = negative changes and EMERGENCE occurs

positive changes = SUBMERGENCE

Question 13

what can cause sea level to rise relatively

Answer 13

1. sea level falls + land rises, remains the same or falls at slower pace
2. sea level remains fixed while land level rises
3. sea level rises, land rises at faster pace

Question 14

what can also affect landforms as well as sea level change

Answer 14

1. discordant/concordant coastline
2. relief of land
3. special local factors (eg was coast glaciated before sea level change)

Question 15

what are the landforms of submergence?

Answer 15

• ria
• fjord
• dalmation coast

Question 16

what are landforms of emergence

Answer 16

• raised beach

Question 17

what is a RIA and how is it formed (example?)

Answer 17

• former river valley floods and opens into sea
• caused by eustatic reasons of sea level rise, isostatic reason of land sinking below sea level
• Pourtsmouth Harbour in Hampshire, submergent coastline

Question 18

what is a FJORD and named example

Answer 18

• a fjord is a drowned glacial valley
• formed when glacier retreats
• has steep rising walls, straighter long profile and is deeper than a ria due to glaciers over deepening valley
• west coast of Norway

Question 19

what is a DALMATION coast and how is it formed (example)

Answer 19

• concordant coastline produced by geological structure of folds parallel to coast
• series of longitudinal river valleys next to the coast that have been flooded (synclines) leaving parallel ranges of watershed ridges as islands
• tectonic forces produced by african/eurasian collision compressed limestone causing anticlines and synclines

Question 20

what is a RAISED beach

Answer 20

• beach above shoreline not reachable by waters at high tide
• sometimes called marine terrace
• formed by wave action when close to waterline
• Ballyhillin Beach in mainland Ireland

Question 21

what is a RELICT CLIFF

Answer 21

a cliff that has been abandoned by sea level fall displaying CASS

emergent landform

Question 22

what is an ELEVATED MARINE PLATFORM

Answer 22

wave cut platform which now exists as extensive flat area in front of relict cliff above wave action

Question 23

what is the main positive impact of the coast on humans

Answer 23

attracts human activities - fishing, tourism, port development, settlement

Question 24

what physical resources make people travel to the coast

Answer 24

• scenery (eg cliffs)
• ecosystems (eg coral reefs)
• sandy beaches
• sunny climates
• high quality seawater free from strong currents and rip tides

Question 25

what human resources make people travel to the coast

Answer 25

• cultural attractions
• heritage resources
• quality provision of services
• leisure facilities
• watersports