Coasts Flashcards
What is the name of a holistic view on a bay?
Shoreline Management Plan
what is the name for the area at the back of the beach?
backshore
How does a Fjord form?
Through the melting of Glaciers, a previously V-Shaped valley becomes a U-shaped Valley. Due to eustatic sea level rise, the valley becomes submerged causing it to flood. Also meaning it is surrounded by mountainous regions.
Where do fjord tend to form?
Norway- Sognefjord
Canada- Saguenay
Alaska
What is a swash aligned beach?
A beach where the waves have shaped it by arriving parallel to the shoreline, usually due to wave refraction. This makes littoral drift minimal.
What is Eustatic sea-level rise?
It is sea level rise on a global scale, for example due to thermal expansion.
What is isostatic sea level rise?
When the sea level rises but in one specific place. Usually occurs due to glacial decompression.
What is a drift aligned beach?
A beach likely to experience littoral drift as the swash arrives at a 45 degree angle, and the backwash perpendicular to the beach. This consequently pushes sediment up the beach.
How does a rip-current form?
When a series of waves are plunged at the shoreline, causing a build up of water. This is then met with resistance from newly breaking waves and the backwash. This forms an x shape current.
What are the types of energy at the coastline?
Currents
Tides
Wind
Waves
What are the main zones on an active coastline?
Offshore
Inshore
Foreshore
Backshore
How do waves form?
Air moves across the surface of the water with friction, creating ripples. In open water an orbital motion begins to occur. Once reaching the shore, the orbital motion creates a crest, and begins to occur horizontally driving it onto the beach, and breaking as a wave.
What are the key features of constructive waves?
Long wavelength
strong swash
weak backwash
sediment deposition
more gentle beach profile, which gradually becomes steeper with deposition.
What are key features of destructive waves?
short wavelength
has a long fetch, creating high energy
weak swash
strong backwash
reduction of sediment
steeper beach profile, due to sediment reduction.
What is a neap tide?
The moon is at a 90 degree angle to the sun.
The gravitational pull acts against each other to create lower high tides, and higher low tides.
They have a small tidal range.
What is a spring tide?
The moon is in line with the sun, usually a full or new moon.
The gravitational pull acts together to create higher high tides, and lower low tides.
They have a large tidal range.
What is wave refraction?
When wave fronts are distorted as they approach a discordant coastline. This forces the waves to become focussed towards the headlands.
Occurs when the waves move from deep water into shallow.
What are the different types of weathering at the coastline?
Chemical- Involves a chemical reaction, where salts may be dissolved.
Biological- The breakdown of rocks through organic activity.
Mechanical- The breakdown of rock without any chemicals, usually through methods such as Freeze thaw.
What is Soil creep?
A slow form of mass movement, where soil particles move downhill creating teracettes. Occurs on a slope.
What is Solifluction?
Similar to soil creep, but only occurs in colder climates. During summer, the top layer thaws and becomes highly saturated. This “active layer” moves slowly downhill with the vegetation.
What is a land slip?
occur in weak land, such as clay and sand. Usually these lie above a layer of impermeable and permeable rock, causing a build up of water pressure between the rocks. This causes the land to slip.
Explain the process of Hydraulic action.
Once a wave crashes against the rock, the air get pressurised and trapped within cracks in the rock. This then expands with wave retreat, weakening the joints in the cliff.
What is the sediment cell?
Usually a stretch of the coastline, between two prominently headlands. There are 11 in the UK.
What is the sediment budget?
The material in the sediment cell that is lost and gained.