EQ3 2B.8 Flashcards
(11 cards)
What is rapid coastal erosion caused by?
When marine and geological processes combine
Geological - lithology/geological structure
Marine - long wave fetch, strong LSD
How can human activity affect coastal recession
By interrupting the operation of the sediment cell eg construction of dams
What is dredging
Removal of sediment from a beach, sea, river
Sand + gravel scooped up for use by construction industry/to make river mouths + estuaries navigable
What is weathering
Breakdown of rocks above high tide mark
What is mass movement?
Downslope movement of material under the influence of gravity
How do mass movement and weathering work tg to influence rates of coastal erosion
Weathering weakens rocks above high tide mark, making mass movement easier by weakening/exploiting joints
Repeated mass movement leads to rapid coastal recession
How is the rate of coastal recession affected by wind direction and fetch?
Onshore winds from prevailing win direction creates destructive waves
Larger fetch inc wave strength
- inc rate
How is the rate of coastal recession affected by tides?
High tides allow waves to reach further inland with more energy
Spring tides (x2/lunar month) cause very high water levels
+SLR (1cm slr = 1m horizontal erosion)
inc rate
How is the rate of coastal recession affected by storms?
Low pressure systems create powerful destructive waves
Climate change inc storm freq and intensity
How is the rate of coastal recession affected by seasons?
Winter - greater temp contrasts, more freq intense storms, high erosion
ENSO
How is the rate of coastal recession affected by weather systems
UK is in between warm tropical and cold polar air mass, has variable pressure systems
Anticyclones (high p) cause calm conditions - low recession.
Depressions (low p) cause strong winds + waves - rapid recession.
