Coasts EQ3

Question 1

What are eustatic changes?

Answer 1

exchange of water between world’s oceans, ice sheets and glaciers

Question 2

What are examples of eustatic changes?

Answer 2

Thermal expansion

Question 3

What are isostatic changes?

Answer 3

process by which earth’s crust seeks to reach equilibrium following loading or unloading of ice

Question 4

What are examples of isostatic changes?

Answer 4

Accretion- creation of new land
Subsidence of ground- soil and rock sinking not crust

Question 5

What are other reasons for sea level change?

Answer 5

thermohaline circulation- big currents that move water around the world
seafloor spreading

Question 6

What are emergent features?

Answer 6

raised beaches- where beaches formed before sea level dropped, common in west Scotland
relict caves, stacks, stumps and arches- old coastal features formed when sea levels were higher

Question 6

What is relative sea level change?

Answer 6

result of all factors, not the same everywhere

Question 7

What are submergent features?

Answer 7

Ria- sea levels rise and flood river valley
Fjord- glacial valleys that have been flooded by sea water

Question 8

What areas are at risk of contemporary sea level change

Answer 8

Kiribati Islands
Jakarta

Question 9

Why are the Kiribati Islands at risk from sea level change?

Answer 9

height above sea level is only 2m and sea levels rise at rate of 1.2cm a year
first climate refugees and people being displaced
gov moved some of the people to Fiji

Question 10

Why is Jakarta at risk from sea level change?

Answer 10

by 2050 majority underwater
sinking by 25cm a year
water extracted on an industrial scale causing soil to sink into gaps

Question 11

What areas are at risk from tectonic sea level change?

Answer 11

Japan as crust becomes displaced and causes oceans to rise

Question 12

What are physical factors that influence coastal recession?

Answer 12

wave fetch/type of wave
lithology
geological structure
human influence
amount of deposition
longshore drift

Question 13

What is an example of how physical factors influence coastal recession?

Answer 13

Holderness Coastline
fastest eroding coastline in Europe
large fetch from northern winds and deep water makes waves very powerful

Question 14

What are human factors that influence coastal recession?

Answer 14

hard engineering
dredging

Question 15

What is an example of how human factors influence coastal recession?

Answer 15

Nile Delta
creation of Aswan Dam increases erosion rates
reduced sediment volume from 130 mill tons to 15mill tons
erosion rates jumped from 25m to 200m due to sediment starvation

Question 16

How do sub-aerial processes affect rates of recession?

Answer 16

weathering weakens rocks above high tide mark, easier for mass movement

Question 17

What are the different factors that affect rate of recession at different time scales?

Answer 17

wind direction + fetch
tides
storms
seasons

Question 18

What are factors that can increase flood risk?

Answer 18

topography
subsidence
vegetation
sea-level rise
storm surge events

Question 19

How did these factors increase flood risk in Bangladesh?

Answer 19

topography- lies on flood plains of 3 main rivers , 46% of pop live less then 10m above sea level
subsidence-sunk by 1.5m in last 50 years
vegetation- lost 35% of mangrove trees + 50% of salt marshes causing coastline to recede 200m a year
storm surge- 6m by cyclone sidr

Question 20

What were the cyclone Sidr impacts?

Answer 20

category 4 storm
strong winds of up to 223km/hr
storm surge of 6m

Question 21

What were the effects of the storm surge in the UK 2013/2014?

Answer 21

caused by sea shape, coastline, depth, high seasonal tides and strong winds
1400 homes flooded and evacuated
cost damaged of £100mill
lost of significant cliff erosion
Thames barrier closed to protect London

Question 22

How did climate change influence coastal flooding during hurricane sandy?

Answer 22

$8bill damage
water around New York rose around 4 inches in 100 years as a result floodwaters reached around 36,000 more homes and affected 71,000 more people

Question 23

How will climate change influence threat of coastal flooding?

Answer 23

sea level change- low level areas and areas with subsidence are more at risk causing land to be lost
increasing sea surface temps- allow more tropical storms to form so more areas affected