coastal processes

Question 1

how do waves form

Answer 1

by winds blowing over the sea. friction with the surface of the water causes ripples that develop into waves. tsunamis form when earthquakes or volcanic eruptions shake the sea bed.

the distance that wave-generating winds blow across the water is called the fetch

Question 2

what happens when waves reach the coast

Answer 2

in the open sea, there is little horizontal movement of water
circular orbit in open water
friction with seabed distorts circular motion
increasing elliptical orbit as water becomes shallower, and waves move forward.
the wave breaks and collapses onto the beach.
water returns as backwash
water rushes up beach as wash

Question 3

define and describe constructive waves

Answer 3

formed by storms often hundreds of kilometers away. common in summer

low waves with wave crest far apart. gently sloping wavefronts. breaking wave push large amounts of sand and pebbles up the beach

Question 4

define and describe destructive waves

Answer 4

formed by local storms close to the coast. common in winter
waves close together. waves become high with a steep wavefront. breaking waves plunging down onto the beach with little forward swash
wrong backwash erodes sand and pebbles and can destroy the beach

Question 5

Types of Weathering

Answer 5

Carbonation

mechanical

Question 6

Carbonation

Answer 6

The weathering of rocks by chemicals is called chemical weathering. Rainwater is naturally slightly acidic because carbon dioxide from the air dissolves in it. Minerals in rocks may react with the rainwater, causing the rock to be weathered

Question 7

Mechanical

Answer 7

Mechanical weathering is caused by physical changes such as changes in temperature, freezing and thawing.

Water gets into cracks in rocks, freezes when the temperature drops below 0’c, prising the rock apart. When the water melts, a larger crack develops. Over time this causes rocks to break apart.

Question 8

Freeze-thaw weathering stages

Answer 8

Water seeps into cracks and fractures in the rock.

When the water freezes, it expands about 9%. This wedges apart from the rock

With repeated freeze-thaw cycles, the rock breaks off.

Question 9

Mass Movement steps

Answer 9

1 Rain saturates the permeable rock above the impermeable rock making it heavy.

2 Waves or a river will erode the base of the slope making it unstable.

3 Eventually, the weight of the permeable rock above the impermeable rock weakens and collapses.

4 The debris at the base of the cliff is then removed and transported by waves or a river.

Question 10

What is Deposition?

Answer 10

When the sea or river loses energy, it drops the sand, rock particles, and pebbles it has been carrying. This is called deposition.

Deposition happens when the swash is stronger than the backwash and is associated with constructive waves.

Question 11

Erosion

Answer 11

The breakdown and transport of rocks

Question 12

Attrition

Answer 12

Rocks that bash together to become smooth/smaller

Question 13

Solution

Answer 13

A chemical reaction that dissolves rocks

Question 14

Abrasion

Answer 14

Rocks hurled at the base of a cliff to break pieces apart

Question 15

Hydraulic Action

Answer 15

Water enters cracks in the cliff, the air compresses, causing the crack to expand.

Question 16

Types of Erosion

Answer 16

Attrition

abrasion

Hydraulic Action

Solution

Question 17

Types of Transportation

Answer 17

Solution

suspension

traction

saltation

Question 18

transportation

Answer 18

A natural process by which eroded material is carried/transported.

Question 19

Solution

Answer 19

Minerals dissolve in water and are carried along.

Question 20

Suspension

Answer 20

Sediment is carried along in the flow of the water.

Question 21

Saltation

Answer 21

Pebbles that bounce along the sea/river bed

Question 22

Traction

Answer 22

Boulders that roll along a river/sea bed by the force of the flowing water