systems and processes Flashcards
(35 cards)
what is a source of energy for a coastal environment?
wind (south easterly wind)
how does wave refraction occur?
it occurs when energy is concentrated at the headland and the wave bends and the energy is dissipated into bays either side
what happens when a wave enters shallow water?
The front of the wave slows and the wavelength shortens which causes the height to increase
What is wave energy affected by? (3 things)
strength of wind
duration of wind
the fetch
What do constructive waves look like?
they are low surging waves with a long wavelength
what do destructive waves look like?
they are high plunging waves with a short wavelength
which type of wave causes beach gain
constructive wave
Which type of wave causes beach loss
destructive wave
What is the beach profile needed for a destructive wave?
steeper but over time flattened
What is the beach profile needed for constructive wave?
gentle but over time made steeper
What is a marine process?
a process that occurs on a coastline and operates with the sea
What is a sub aerial process?
process that slowly breaks down the coastline
How does freeze thaw weathering work?
water fills crack in rock, then freezes, then breaks the rock as it expands
How does salt crystallisation weathering work?
saline creeps into the rocks and evaporates, leaving salt crystals behind
How does wetting and drying weathering work?
clay rocks expand when they are wet and contract when they are dry. this causes cracks that are prone to other weathering methods
What is a mass movement rockfall?
When pieces of rock fall off the cliff edge.
What is a mass movement mudflow?
saturated soil falls down a slope
What is a mass movement landslide?
Large blocks of rock sliding downhill
What is a mass movement rotational slip?
saturated soil slumps down a curved surface
What is erosional hydraulic action?
The force of fast flowing water hitting the bed and banks and forcing water and air into cracks. The changes in air pressure cause the river bed to weaken
What is erosional wave quarrying?
High energy waves hit the cliff face and enlarge joints and have the power to remove large chunks of rock
What is erosional cavitation?
compressed air in joints causes water to be under a lot of pressure and air comes out of the joints in fizzing enlarging fissures
What is transportation traction?
large stones and boulders roll along the seabed by moving water
What is transportation saltation?
small stones bounce along seabed, particles are thrust up and down causing continuous bouncing