Coastal risks Flashcards
Name 3 factors effecting sea level change
- high & low tides
- atmospheric air pressure
- winds
Definition of isostatic change
local rise/ fall in land level
Definition of eustatic change
rise/ fall in water level
-caused by change in vol of water
What is marine regression
when seabed is exposed as sea level drops- producing emergent coast
What is marine transgression
when areas of land flood- coastline is drowned- producing submergent coast
What is a eustatic fall in sea level
during glacial periods- when ice sheets form on land in high latitudes- water evaporated from sea is locked up on land as ice
-leading to global fall in sea level
What is a eustatic rise in sea level
at end of glacial period- melting ice sheets return water to sea- sea level rises globally
What is a isostatic fall in sea level
-post-glacial adjustment
when ice sheets melt land surface surface slowly rebounds upwards
-post-glacial adjustment slowly lifts land surface out of sea
What is a isostatic rise in sea level
land can ‘sink’ at coast- deposition of sediment (accretion)
Definition of accretion
occurs when sediment is added to landform by deposition
-can build up to form new land
Definition of post-glacial isostatic adjustment
uplift experienced by land following removal of weight of ice sheets
What are emergent coastlines
coastlines that have formed where water level has fallen/ land has risen
-happens due to isotatic change
What are submergent coastlines
coastlines that have been flooded due to rise in sea leve;s
-happens due to eustatic sea level change
name the most common coastal feature of submergent coastlines
ria
What is a ria
drowned river valley in an unglaciated area caused by sea level rise flooding river valley
