Term
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Definition
| The coast is defined as "where the land meets the sea". Typically zoned due to fluctuations in tides and seasonal weather. |
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Term
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Definition
Force: Gravity (Sun and Moon)
Wave Type: Tides |
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Term
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Definition
Force: Displacement (Earthquake, Volcano, Landslide)
Wave Type: Tsunami |
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Term
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Definition
Force: Wind
Wave Type: Ripples, chop, swell |
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Term
| What happens as waves come closer to shore and depth decreases? |
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Definition
-wavelength DECREASES
-velocity DECREASES
-amplitude INCREASES
-period REMAINS CONSTANT |
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Term
| What are some processes that effect coastlines? |
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Definition
-sea level changes
-tectonics: subsidence and uplift
-coastal erosion - short term: storms, long term: wave action |
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Term
| Wave Action and Coastal Erosion |
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Definition
-waves that strike the coastline at an angle will be refracted into near parallelism with the coast
-because of this, wave rays (lines perpendicular to wave crests) tend to focus towards headlands
-hence wave energy is greatest at headlands and least in bays
-these processes will tend to erode headlands and cause sediment infilling of bays |
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Term
| Coastal erosion: Wave-cut platforms |
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Definition
1. Sea erodes cliff
2. waves cut notch into cliff, weakening cliff
3. Cliff collapses |
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Term
| What is a longshore current? |
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Definition
| Wave refraction also leads to a flow vector parallel to the coastline called a longshore current.This can transport large volumes of sediment along the coast. |
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Term
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Definition
-very dynamic
-these islands tend to undergo rapid erosion
-buildings, etc. are vulnerable to damage during storms |
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Term
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Definition
-Navigation
* Jetties
-Erosion along coastlines can be controlled (at least partially) by implementing protective structures
* Groins
* breakwaters
* revetments
* seawalls
* beach nourishment |
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Term
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Definition
-long island things that stick out into the sea
-designed to enhance and maintain navigation
-prevent blockage of inlet by longshore drift |
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Term
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Definition
-perpendicular to the shoreline
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-create of widen beaches by capturing sand moving along the shoreline (littoral drift) |
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Term
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Definition
-parallel to the shoreline
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-attempt to break incoming waves
-protect shorelines/facilities (e.g. marina) from wave action and storm surges |
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Term
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Definition
-vertical structures
-parallel to the shoreline
-separate land and water areas
-prevent erosion and other damage due to wave action |
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Term
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Definition
-parallel to the shoreline
-sloped to mimic the natural slope of the shoreline profile
-dissipate wave energy as the wave is directed up the slope |
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Term
| Erosion Control vs Beach Loss |
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Definition
-beaches on chronically eroding shores can maintain their natural width as they slowly retreat landward
HOWEVER...
-beach loss eventually occurs in front of a seawall where there is chronic erosion |
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