Coasts Eq3

Question 1

What are eustatic changes

Answer 1

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

Question 2

What are isostatic changes

Answer 2

The process by which the earth’s crust seeks to reach equilibrium following loading or unloading by ice e.g Scotland has positive isostatic change due to melting of ice sheets

Question 3

What is relative sea level change

Answer 3

The result of all the factors that affect sea level change

Question 4

What is thermal expansion

Answer 4

Water expands when it warms

Question 5

How does tectonic activity cause sea level change

Answer 5

Earthquakes can cause tectonic plates to vertically displace

Question 6

What is accretion

Answer 6

When new land is created (e.g by deposition, so sea levels appear to go down)

Question 7

What is subsidence

Answer 7

Sinking of land (e.g pumping water out of the ground in Jakarta)

Question 8

What is thermohaline circulation

Answer 8

Water moves away from some areas and towards others in the ocean

Question 9

What is ria

Answer 9

On a submergent coast, the sea level rises and floods a river valley

Question 10

What is a fjord

Answer 10

On a submergent coast, the sea level rises and floods a glacial valley, with steep walls of rock on either side

Question 11

What is a raised beach

Answer 11

On emergent coasts, areas of beach deposits formed when the sea levels were higher, they can be seen in Scotland

Question 12

What are relict caves/arches/stacks

Answer 12

On emergent coasts, the sea levels sink and caves, arches and stacks are revealed

Question 13

Example of a coastline at risk from sea level change as a result of global warming

Answer 13

Kiribati islands, sea levels are rising at 1.2cm per year, they are approximately 2 metres above sea level, government has moved some people to Fiji

Question 14

Example of human factors affecting sea level change: Jakarta

Answer 14

Subsidence is occuring due to overpopulation, by 2050 most of the city will be underwater

Question 15

How are physical and human factors influencing rapid coastal recession on the Holderness coast

Answer 15

Physical: made up of boulder clay, subaerial processes (landslides and weathering)
Human: rock groynes cause coast further down to erode 3-4 times faster

Question 16

How are human factors influencing rapid coastal recession in the Nile Delta

Answer 16

Rates of erosion have increased from 25 metres per year to over 200
Aswan high dam created which trapped sediment in the reservoir, causing less deposition further down the river

Question 17

How are human factors influencing rapid coastal recession at Mauritania

Answer 17

Groynes built which increases erosion further down the coast
Basal scouring occurs as sea wall causes increased erosion of beach and base of sea wall

Question 18

How are physical factors affecting coastal recession in Bangladesh

Answer 18

Low lying land - 10% is less than 1 metre above sea level
Isostatic changes
Flood plain of three major rivers

Question 19

How are human factors affecting coastal recession in Bangladesh

Answer 19

Subsidence
Vegetation removal (50% of salt marshes lost)

Question 20

What is a storm surge

Answer 20

A change in sea level caused by intense low level pressure systems from cyclones

Question 21

Bangladesh cyclone Sidr 2007 impacts

Answer 21

Extensive flooding of low lying areas
Damaged infrastructure
Contaminated drinking water
Electricity and communications cut off

Question 22

Holderness 2013 storm surge impacts

Answer 22

18,000 had to be evacuated, 800,000 properties affected

Question 23

Hurricane Sandy reasons for significance and impacts

Answer 23

Hurricane would have moved into the ocean, but area of high pressure caused it to move into New York
Tide in the US was already at its highest point
Caused 286 deaths, caused New York tide to increase by 4 metres

Question 24

How will global warming affect storm surges

Answer 24

Causes oceans to become warmer, so increased number and intensity of tropical storms
The sea will become warmer further north and south, so there will be more variation in the pattern of storms
Global sea levels will rise due to melting ice caps