COASTAL ENVIRONMENTS Flashcards
(33 cards)
How do people interact with the coastline?
Fishing, usually for selling.
Receiving imports and shipping exports by ship
Leisure activities or tourists/tourism.
Building homes with attractive views.
How is climate change likely to affect the coastline?
The warmer weather makes the sea warmer, which makes it more prone to hurricanes (which are fueled by warm air rising). Hurricanes also often bring storm surges which are exacerbated by the sea’s high water levels.
What sort of sediment is found at the coastline?
Mud, sand & clay.
How does the population living within 100km of a coast affect the likelihood of coastal cities?
Higher population living within 100km of a coast means there is more likely for a coastal city to form.
How does a country’s central weather conditions affect the likelihood of coastal cities?
Harsher weather conditions (very cold or very hot) means it is less likely for a coastal city to exist.
What is a coastal zone?
A coastal zone is the general area where land meets a larger body of water such as the sea or ocean.
How does rock strength affect the coastline of a country?
Hard rock forms rugged coastlines, soft rocks form low flat coastlines. Rocks such as granite are more difficult to erode and would take longer to affect the coastline, whereas rocks such as chalk or sandstone erode more easily and would very quickly cause the coastline to recede.
Define concordant & discordant geological structure
Concordant: rock lies in bands that run parallel to the coastline.
Discordant: rocks lie in bands at the right angles to the coast.
What are the biggest influences on coastal zones?
a) Weather
b) Rock/sediment type
c) Wind strength/direction
d) Temperature
e) Storms
f) Potential sea defences (coast of sea defences)
Define backshore, foreshore & nearshore
Backshore: Stretches landwards from the high water level, can be reached by high storm waves during rough weather.
Foreshore: Lies between the low water level and the high water level, covered with water during high tide.
Nearshore: The region of the sea or sea bed which is relatively close to the shore.
What are the two types of waves?
Constructive & Destructive
What is wave anatomy?
Wave frequency: the number of wave crests passing point A each second.
Wave period: the time required for the wave crest at point A to reach point B.
How do waves break?
Waves break when they reach a shallow coastline where the water is half as deep as the wave is tall. As a wave travels across the open ocean, it gains speed. When a wave reaches a shallow coastline, the wave begins to slow down due to friction.
How are breaking waves formed?
Friction along the bottom slows the base of the wave down while the water at the surface continues forward. When the wave steepness (the ratio between wave height and wavelength) exceeds a ratio of 1:7, it becomes unstable and breaks.
What is the difference between constructive & destructive waves?
X
What factors affect erosion?
-Energy Factors - waves, tides, currents and winds.
-Material Factors - sediment supply, beach/rock platform width, rock resistance, rock structure and dip.
-Shore Geometry - offshore topography (bathymetry), orientation of coast, direction of fetch.
What are the three types of weathering?
Mechanical, chemical & biological.
What are sub-aerial processes?
The processes of weathering and mass movement.
What are the main influences on transportation & deposition?
Angle of wave attack, tides & currents.
What is longshore drift?
The transportation of sediments along a coast parallel to the shoreline, the sediment moves in a zigzag pattern along the coast due to the swash a backwash.
What is a tide?
The alternate rising and falling of the sea, usually twice in each lunar day at a particular place, due to the attraction of the moon and sun.
What factors influence the tide?
Centrifugal force on the ocean, gravitational pull from the moon & the Earth’s rotation.
When do spring tides occur?
after a new or full moon, there is the greatest difference between high and low water. Spring has no relation to the season - but with the act of springing forth.
When do neap tides occur?
just after the first or third quarters of the moon there is least difference between high and low water.
