Systems and processes Flashcards
(40 cards)
What are the main components of a coastal system?
Inputs, Processes, Outputs
Inputs include energy (waves, tides, wind, currents), sediment (from rivers, cliffs, offshore sources), and human activity (coastal defences, dredging). Processes include erosion, transportation, deposition, and weathering. Outputs include landforms (beaches, spits, dunes, cliffs), sediment loss to deep water, and dissipation of wave energy.
What drives wave formation in coastal systems?
Wind energy, Fetch, Water depth
Stronger wind results in more powerful waves and determines fetch, affecting wave energy.
Define constructive waves.
Low height, long wavelength, strong swash, weak backwash
Constructive waves promote deposition.
Define destructive waves.
High height, short wavelength, weak swash, strong backwash
Destructive waves promote erosion.
What are spring tides?
Higher tidal range
Spring tides lead to more erosion.
What are neap tides?
Lower tidal range
Neap tides result in less energy.
What is longshore drift?
Waves approach at an angle, moving sediment laterally
It is a key process in sediment transport along the coast.
What is hydraulic action in marine erosion?
Air and water forced into cracks, breaking rock
It is one of the processes of marine erosion.
What is abrasion (corrasion)?
Waves throw sediment against cliffs, wearing them away
It contributes to the erosion of coastal landforms.
4 types of transportation ?
Traction - heavy boulders rolled along bed, Saltation - smaller pebbles bounced along bed, Suspension - fine material carried within the water, Solution - materials dissolved in water and carried invisibly.
It is one of the methods of sediment transport.
What occurs when wave energy decreases?
Deposition
This leads to the formation of beaches, spits, bars, and dunes.
What are the types of weathering in sub-aerial processes?
Mechanical, Chemical, Biological
Mechanical includes freeze-thaw and salt crystallisation; Chemical includes carbonation and oxidation; Biological includes plant roots and burrowing animals.
What is slumping in mass movement?
Saturated cliffs collapse - section of soil or rock moves downhill along a curved, concave surface due to gravity.
It is a type of mass movement affecting coastal areas.
What is dynamic equilibrium in coastal systems?
Balance between erosion and deposition
It is crucial for maintaining coastal stability.
What effect does climate change have on coastal systems?
Rising sea levels, increased storm intensity
These changes can exacerbate coastal erosion and alter sediment transport.
What is wave refraction ?
Bending of waves as they approach the shore due to waves slowing down in shallow waters, leads to concentrated erosion.
Types of mass movement ?
Soil creep, Landslides, Rockfalls, Rotational slumping, Mudflows
What are aeolian processes ?
Transport and deposition of sediment by wind.
What is surface creep - Aeolian process ?
Wind rolls or slides sand grains along the surface.
What is saltation - Aeolian process ?
Where the wind is strong enough to temporarily lift grains into the airflow of heights up to 30 metres.
What is a landslide ?
Occur on cliffs made form softer rocks which slip as a result of lubrication usually following heavy rainfall.
What is a rockfall ?
Occur from cliffs undercut by the sea or on slopes affected by mechanical weathering.
What is a mudflow ?
Heavy rain causes large amount of fine material to flow downhill, soil is too saturated so surface layer become very fluid and flow downhill.
What is rotational slumping ?
When softer material overlies more resistant material.
