sea level change

Question 1

What is isostatic change? What is it caused by? examples where this is/has happened:

Answer 1

Isostatic change are local changes in sea level d2:
1. isostatic subsidence- glaciers weigh down earth-> land subsidence
2. tectonic activity-> land subsidence
e.g. 2004 Indian Ocean earthquake= Bandeh Aceh sunk by 0.5m

Question 2

What is eustatic change? How does thus occur? According to the ICC how would this have changed by 2100?

Answer 2

eustatic change= global sea level change d2:
1. thermal expansion- water expands when warm-> volume of water increases= sea level rise
2. glacial processes- last ice age sea levels were 100m lower as more water was stored in ice caps-> global warming= melted, sea level rise

2100- 0.3-1m SLR- globally

Question 3

How has sea level changed since the last glacial maximum? (20,000 years ago)

Answer 3

• sea levels now are 130m higher
• last time sea levels were higher than today was 130,000 years ago
• SL rise slowed 8000 years ago and levelled to current heights 3000 years ago

Question 4

What are emergent landforms? give an example

Answer 4

emergent landforms are caused when the land has been raised in relation to the coastline as sea levels have decreased
e.g. raised beaches

Question 5

what are raised beaches? give an example of one:

Answer 5

areas of formed wcp where beaches are higher than present sea levels
- often feature relic cliffs, arches, stacks, caves etc
e.g. Isle of Arran

Question 6

what are submergent landforms? name 3 examples:

Answer 6

submergent landforms occur when sea level rises and the coast sinks in relation to the sea e.g. rias, fjords, dalmatian coasts

Question 7

what are rias?

Answer 7

rias occur when rising sea levels flood narrow winding inlets and river valleys
can be isostatic or eustatic
often have a dendritic basin system
deeper at the mouth, water depth decreases further inland
e.g. sydney harbour

Question 8

what are fjords?

Answer 8

flooded glacial valleys d2 glacial erosion (abrasion and plucking-> glacial troughs)= flood d2 sea level rise + isostatic readjustment
e.g. sogne fjord, norway

Question 9

what are Dalmatian coastlines?

Answer 9

geology-> valleys run parallel to the coast-> flooded d2 slr= a series of narrow, long and rugged islands e.g. croatia