Coasts: Coastal landscape development - Sea Level Change Flashcards
Eustatic, isostatic and tectonic sea level change. Major changes in sea level in the past 10,000 years.
What are the 2 different types of sea level change?
Isostatic
Eustatic
What is isostatic sea level change?
Changes in sea level as a result of the changing level of the land.
What is eustatic sea level change?
Changes in sea level as a result of the changing level of water in the oceans.
On what scale does isostatic sea level change occur?
Local/regional
On what scale does eustatic sea level change occur?
Global
Where were sea levels 18000 years ago compared to now?
110m lower
Describe the changes in sea level in the last 10,000 years.
10,000 years ago - Doggerland land bridge still linked UK to Netherlands and Denkmark from last glacial maximum.
Sea levels then rose by 10m in 500 years.
Stable for 3000 years pre-industrial revolution.
Mid-19th cenruty - started increasing
How quickly are sea levels currently rising?
3.2mm per year
What is the main reason for current sea level rise?
Thermal expansion
How much is the sea level expected to rise by 2100?
4-6m
What are the 3 causes of isostatic change?
Tectonic activity
Glaciation
Post-glacial readjustment
Give an example of how tectonic activity can cause isostatic change.
Tohoku earthquake, Japan, 2011 - some sections of coastline dropped by 0.84m
How does glaciation cause isostatic change?
During an ice age glaciers and ice sheets form over the land in areas. The land surface becomes pressed into the upper layer of the mantle causing sea levels to rise.
What is isostatic recovery?
When the asthenosphere rebounds following the melting of ice sheet and glaciers on land
What process involved in post-glacial readjustment causes isostatic change?
Isostatic recovery
