eq2 Flashcards

1
Q

hurricanes

A

tropical storms found in the Atlantic Ocean

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2
Q

cyclones

A

tropical storms found in the Indian Ocean

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3
Q

typhoons

A

tropical storms found in the Pacific Ocean

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4
Q

tropical storms

A

storm event that has very low atmospheric pressure

  • leads to evaporation
  • air rising
  • cooling and condensing
  • cumulunimbus clouds
  • precipitation
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5
Q

wave formation

A
  • wind blows across surface of ocean/lake
  • friction
  • water particles move in orbital motion, though not forward = oscillation waves
  • wave energy moves in a column (up to down in circles)
  • energy is passed forward
  • as wave travels across, bottom drags along ocean floor
  • creates friction
  • upper part moves faster than rest as depth decreases
  • upper part tilts forward as the dragging becomes stronger
  • makes wave break in the surf zone
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6
Q

factors that affect strength of a wave

A
  • wave height
  • fetch
  • wave refraction
  • depth (affects height)
  • wind speed
  • hydro-meterological events
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7
Q

examples of fetch

A
  • atlantic large

- mediterranean small

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8
Q

examples of wave refraction

A
  • st David’s head
  • st Ann’s head
  • st Bride’s bay
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9
Q

characteristics of constructive waves

A
  • low-surging waves
  • long wavelength
  • strong swash, weak backswash
  • beach gain (constructive)
  • low flat wave height
  • strong swash pushes sediment up the beach
  • weak backswash leads to deposition of sediment at the top of the beach
  • 6/10 minutes
  • gentle gradient
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10
Q

characteristics of destructive waves

A
  • high energy waves
  • short wavelength
  • weak swash, strong backswash
  • beach loss (destructive)
  • high wave height
    strong backswash erodes material
  • 11/15 minutes
  • steep waves
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11
Q

Hydro-meterological events

A

tropical storms, flooding, extreme weather

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12
Q

berm

A

created especially in macro tidal areas such as Cornwall in Atlantic

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13
Q

erosional processes; abrasion

A
  • as waves advance, pick up sand and pebbles from seabed.

- then, break at base of cliff. transported material is hurled at the cliff foot- chips away rock

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14
Q

erosional processes; hydraulic action

A
  • when wave advances, air is trapped + compressed
  • when retreats, compressed air expands again
  • continuos process weakens joints and cracks in cliff
  • force of rock can also hammer a rock surface.
  • at high velocities, bubbles form in water + collapse, they erode by hammer-like pressure effects.
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15
Q

erosional processes; corrosion

A
  • when cliffs are formed made by alkaline rock (chalk or limestone), or alkaline cement that bonds the rock particles together, solution containing weak acids in seawater can dissolve them
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16
Q

attrition

A
  • gradual wearing down of rock particles by impact and abrasion
  • pieces f rock are moved by waves, tides and currents which gradually reduces their size and makes stones rounder and smoother.
17
Q

how do waves and lithology influence erosion

A
  • in booklet
18
Q

wave refraction

A
  • when the undersea topography causes the wave fronts to slow, bend and aim to break parallel to shore
  • leads to energy being concentrated on headland (hence more ero)
  • leads to lower energy in bays (hence depo)
    if waves break at angle within the bay, LSD occurs
19
Q

wave cut notch

A
  • erosion caused when waves break against the foot of a cliff. (abrasion, HA, corrosion)
  • undercutting formed = WCT
  • eg: flamborough head, Yorkshire
20
Q

wave cut platform

A
  • as undercutting gets bigger, rock above it too heavy + due to gravity unstable + collapses
  • repeated = cliff retreats
  • leaves behind a wave cut platform
  • as retreats, bigger WCP
  • eg: southerndown, South Wales
21
Q

cliffs

A
  • constant wave action and erosion against cliff foot = steep profile and retreats.
  • steepest where rock strata are vertical or horizontal or have almost vertical joints.
  • gentlest = rock dips towards or away from sea
  • eg: Near Eastbourne, West Sussex
22
Q

caves, arches, stack stumps and blow holes

A
  • caves = joints + faults eroded by abrasion + HA
  • if overlying rock collapses = blowhole
  • if 2 caves join or single cave is eroded through headland = arch
  • top of arch unstable and collapses = stack
  • continue to erode + collapse = stump
  • eg: on Great Ocean Road, Australia
23
Q

traction

A

relatively large and heavy rocks are rolled along the seabed

24
Q

saltation

A

smoother and lighter rocks bounce along the seabed

25
Q

suspension

A

fine, lighter sediment carried in water column

26
Q

solution

A

when disolved sediment is carried

27
Q

what influences sediment transportation- tides + currents

A
  • caused bu gravitational pull of the moon
  • UK has 2 high tides and low tides a day
  • level of tide will determine at what height on foreshore and back shore processes such as depo will be occurring
  • higher tidal range leads to powerful tidal currents, can become rather strong in estuaries and narrow channels
28
Q

what influences sediment transportation- angle of wave attack and LSD

A
  • LSD main transport process
  • strongest LSD = waves approach beach 30 degrees angle
  • swash pushes material up the beach
  • backswash= at 90 degrees, due to gravity, pulls away
  • so, sediment in zig zag up the beach
  • wind and wave direction will determine direction of LSD
  • refraction around headlands can reverse LSD direction
29
Q

drift aligned beaches

A
  • sediment transferred along the coast by LSD

- wave crests break at an angle to the coast, so there is consistent LSD + material moves significantly along the beach.

30
Q

swash aligned beaches

A

sediment doesn’t move much along the beach.

- wave crests approach parallel to the coast, so there is limited longshore movement of sediment

31
Q

bayhead beach

A
  • a seas aligned feature, where waves break at 90d to shoreline and move sediment into a bay, where a beach forms.
  • due to wave refraction, erosion is concentrated at headlands and the bay is an area of deposition.