Coastal Landscape - 2B.7-2B.9

Question 1

What is marine regression and marine transgression

Answer 1

-Regression: where the sea level drops and produces and emergent coast
-Transgresion: where the coastline is flooded and produces a submergent coastline

Question 2

How does marine regression happen (Eustatic and Isostatic)

Answer 2

Eustatic - during glacial times, ice sheets form, water is locked up on land as ice so sea level forms
Isostatic - the weight of ice sheets causes earths crust to sink, as it melts the earth rebounds slowly lifting out of the sea

Question 3

How does marine transgression happen (Eustatic and Isostatic)

Answer 3

Eustatic - melting ice returns to sea at end of glacial period causing sea levels to rise)
Isostatic - Land can sink due to deposition of sediment (accretion), prone in large river deltas

Question 4

How is a raised beach formed

Answer 4

• past glacial sea-level rise was very rapid and drowned many coastlines
• Isostatic rebound mean newly drowned coastlines slowly emerged from the sea

Question 5

What is a Ria

Answer 5

• a drowned river valley in an unglaciated area caused by sea level rise flooding of the river valley making it much wider

Question 6

How are Fjords formed and what are some of the features of them

Answer 6

• Drowned U-shaped, glacially eroded valley
• deeper then adjacent sea
• post-glacial Isostatistic adjustment slowly raises land out of sea

Question 7

What is dredging

Answer 7

-Dredging: scooping sediment up from the sea or river bed for construction or to deepen a channel for large boats

Question 8

How do human activities influence rates of erosion

Answer 8

• dredging reduces the amount of energy dissipated from incoming waves and so increase erosion
• building damns traps sediment from travelling downstream increasing rates of erosion down the coast

Question 9

How did human activities at Hallsands affect the coast

Answer 9

• 1500 tonnes of sediment removed a day to build a naval dockyard in the 1890s
• combined with storms the village fell into the sea on 26/01/1917.

Question 10

What physical factors affect rates of erosion

Answer 10

• long fetch and large destructive waves
• soft, unconsolidated geology
• cliffs with structural weakness
• cliffs vulnerable to mass movement

Question 11

What are the reasons for variation in erosion along the Holderness coastline

Answer 11

• coastal defences in hornsea stopping erosion
• starvation of sediment further south due to groynes
• variations in cliff height and susceptibility to erosion

Question 12

What causes erosion along the holderness coastline

Answer 12

• winter storms when they coincide with high tides
• storms are rare in the summer so erosion in autumn is lower
• north-easterly storms cause most erosion due to long fetch of 1500m from norwegian coast (rare)

Question 13

What is the relationship between air pressure and seas level change

Answer 13

for every drop of air pressure in 10 millibars, the sea level rices by 10 cm. During cyclones, air pressure can be 100 Mb lower raising sea level by 1 m

Question 14

What were some of the impacts of the 2013 flood

Answer 14

• 2 people died (2500 in 1953)
• flooded homes and transport disruptions, however many saved by coastal defences and better forecasting

Question 15

what are some of the components affecting sea level rise

Answer 15

• thermal expansion of oceans as they warm due to GW
• melting of mountain glaciers (Himalayas) increase global water volume
• melting of major ice sheets (Antarctica) will dramatically increase global sea level, when and by how much is still uncertain

Question 16

How is Kiribati under threat from sea level change

Answer 16

• 200 households already flooded contaminating fresh water supplies ( Tebuginato Lagoon)

Question 17

How is Kiribati trying to mitigate the effects of sea level change

Answer 17

• ‘migration with dignity’ effort involves sending people to Australia for basic skills training needed when they permanently migrate
• mass migration to South Tarawa resulting in population density similar to Tokyo

Question 18

How has tectonic activity had localised effects in Sumatra

Answer 18

• satellite images show evidence of and erosion after tsunami
• coastline as a result dropped by 1 m whilst offshore islands raised by 2 m

Question 19

Why is Bangladesh vulnerable to flooding

Answer 19

• worlds most densely populated country
• 46% of the worlds population live less than 10 m above sea level
• lies of food plains of three major rivers
• increased snow melt (due to GW) from Himalayas flows into rivers

Question 20

What were some of the effects of cyclone Sidr (storm surge)

Answer 20

• tidal waves from 5 m to 10 m high
• low lying areas severely flooded with contaminated drinking water
• estimated 3406 deaths / 55000 injuries