Coasts PowerPoint

Question 1

What are the physical factors influencing coastal landscapes?

Answer 1

• winds: speed, direction and frequency
• waves: wave formation, development and breaking
• tides: tidal cycles and range
• currents: global patterns
• geology: lithology and structure

Question 2

the energy of a wave is dependent on

Answer 2

the strength of the wind, its duration and the length of fetch

Question 3

the source of energy for coastal erosion and sediment transport is

Answer 3

wave action

Question 4

wave energy is generated by

Answer 4

frictional drag of winds moving across oceans; and is a result of fetch

Question 5

fetch is

Answer 5

the length of open water which the wind can blow unobstructed

Question 6

how do ocean waves build

Answer 6

Ocean waves build in response to the shear of wind blowing over the water surface. Higher-energy wind yields higher-energy waves. Within a passing wave, water follows a circular path. The circle radius decreases with depth.

Question 7

how do waves break

Answer 7

As a wave approaches shore, friction slows its base.

Water motion in the wave becomes more elliptical, the wave oversteepens, and it crashes ashore as a breaker.

Question 8

what is tidal range

Answer 8

Vertical distance between the high tide and the low tide

Question 9

tidal range- place with highest tidal range

Answer 9

The Bay of Fundy, on the east coast of Canada, is often stated to have the world’s highest tides because of its shape, bathymetry, and its distance from the continental shelf edge

A max range of 16.8 m has been recorded

Question 10

what are spring tides

Answer 10

Spring tides occur twice each lunar month all year long without regard to the season

Question 11

what is a neap tide

Answer 11

When the sun and moons are at right angles to each other, there is least gravitational pull, meaning the tidal range is at its lowest. The neap tide occurs 7 days after the spring tide.

Question 12

Two factors that will affect the horizontal distance over which the shoreline can migrate between high and low tide

Answer 12

• Position of moon (neap and spring tides related to tidal range)
• Slope of shoreline- if tidal range large and slope gentle the position of the shoreline can move a long way leaving a broad tidal flat exposed to the air

Question 13

When a tidal current moves towards the land and away from the sea, it…

Answer 13

floods

Question 14

when it moves toward the sea away from the land it…

Answer 14

ebbs

Question 15

Tidal currents that ebb and flood in opposite directions…

Answer 15

results in horizontal motion producing currents called ‘rectilinear’ or ‘reversing’ currents.

Question 16

2 types of ocean current

Answer 16

1. Surface Currents: located at the ocean’s surface

2. Deep Currents: below 300 metres

Question 17

Thermohaline Circulation

Answer 17

Driven by temperature and salinity, which causes differences in density

Question 18

where may rip currents form

Answer 18

Rip currents may form around low spots in the ocean floor near the shoreline or in breaks between sandbars.
They may also form around human-made structures such as jetties and piers.