Deck 15: Oceans, Shorelines, and Shoreline Processes

Question 1

What are spring tides and neap tides,and what causes them?

Answer 1

When the Moon and Sun are aligned,whether on the same side of Earth or on opposite sides,the forces add together and cause higher high tides,about 20% higher than average high tides.These are spring tides.When the Moon and Sun are at right angles to each other,the Sun's forces cancel some of the Moon's forces,so high tides are about 20% lower than average.These are neap tides.

Question 2

How does the Moon generate tides? Why are there generally two high tides and two low tides a day?

Answer 2

The gravitational pull of the Moon on Earth pulls the water toward it,creating a bulge at the nearest point.Another bulge forms on the opposite side of Earth due to the centrifugal force of Earth's rotation.These two bulges point toward and away from the Moon,and between the two bulges are two troughs since the water is in the bulges.The bulges are high tides,and the troughs are low tides.Earth rotates beneath them,and most shorelines on Earth reach each one once a day,and so have two high tides and two low tides each day.

Question 3

What options do geologists and engineers have in combating the effects of rising sea level?

Answer 3

Options include: building sea walls,restoring beaches by moving sand,building groins and jetties to reduce erosion rates,constructing onshore features to prevent shoreline erosion,and preventing development of shoreline properties.

Question 4

What is a beach,and what are the component parts of a beach?

Question 5

What caused the bulk of the damage that was done by Hurricane Katrina to the city of New Orleans? Why was New Orleans so vulnerable?

Question 6

What are longshore currents,and how do they form? Why are they important to shoreline processes?

Question 7

Describe the way a wave moves and what wave speed measures.

Question 8

What two phenomena cause the tides? Which of these is stronger,and why?

Question 9

Describe how a coral atoll forms.

Question 10

Why must elected official sand city planners of coastal communities understand the geologic processes of shorelines?

Question 11

Outline the factors that create global surface circulation patterns and describe the patterns created.Where are the cold water currents and where are the warm water currents? How does this moderate Earth's temperature?

Question 12

How do rip currents form,and what should you do if you are caught in one?

Question 13

What are winter beaches and summer beaches? How can the same beach have two such different seasonal profiles?

Question 14

What causes a wave to break when it reaches shore?

Question 15

What are barrier islands,and where do they form? How does the sand migrate on barrier islands?

Question 16

What are two ways (one natural and one human-induced)in which the sediment budget of a coastline can become negative?

Question 17

Briefly explain what the effects of rising sea level are on the barrier islands along the United States coastlines and why coastal communities are concerned.

Question 18

In most locations ocean water salinity is in dynamic equilibrium,inputs equal outputs.What does this mean and what are the inputs and outputs for dissolved solids in seawater?

Question 19

Describe how waves are generated.

Question 20

Why do waves bend or refract as they approach shorelines?

Question 21

What is an Exclusive Economic Zone (EEZ)?

Question 22

What characteristics along a seacoast indicate that erosion predominates over deposition?

Question 23

What are the primary agents of sediment transport and deposition along shorelines?

Question 24

How do marine terraces form?

Question 25

Define the photic and aphotic zones in the ocean.

Question 26

Methane hydrates could provide a lot of energy for us to use.Outline the reasons that these resources are not yet being used.

Question 27

What is the most important agent for modifying the equilibrium profile of beaches?

Question 28

In what direction do longshore currents flow?

Question 29

What path do water particles in a wave ideally follow?

Question 30

Briefly explain how sea level could fall in one region while it is generally rising elsewhere.

Question 31

Why do wave sizes in ponds and lakes have less magnitude than those in oceans?

Question 32

How are sea cliffs eroded?

Question 33

What is a wave-cut platform,and how does one develop?

Question 34

What are the two factors that control the absolute rate of sea level rise in a particular shoreline?

Question 35

Describe how a coast can become emergent.

Question 36

How does the budget or volume of sand on a given beach change through the year?

Question 37

How would a country,such as Bangladesh,be affected by a 2 m rise in sea level?

Question 38

How do shoreline processes tend to straighten an initially irregular shoreline?

Question 39

Give a possible reason why beach residents might construct a groin on a beach.What is a probable negative effect of such a construction?

Question 40

What is the cause of rising sea level?

Question 41

The velocity of a wave is calculated as the ____________________ multiplied by the ____________________.

Question 42

If hydraulic action and abrasion undercut headlands,structures known as ____________________ may form.When these join,they form a(n)____________________,which might later collapse to give a(n)____________________.

Question 43

Orbiting molecules of water in a wave touch the sea or lake floor at the depth of the ____________________.

Question 44

The two important types of nearshore currents are ____________________ currents and ____________________ currents.

Question 45

The highest part of a wave is known as its ____________________,and the lowest part is its ____________________.The wave ____________________ is the difference between these two points.

Question 46

The rising tide is also known as the ____________________ tide.The falling tide is known as the ____________________ tide.

Question 47

High water that occurs with the eye of a storm coupled with storm waves reach a shoreline is called ____________________.

Question 48

Energy is transferred from wind to water to create waves by ____________________.

Question 49

The transfer of water from depth to the surface is known as ____________________.The transfer of water in the opposite direction is known as ____________________.

Question 50

The balance between additions and losses of sediment in the nearshore zone is known as the _________________________.

Question 51

The bending of waves toward shore as they approach from an oblique angle is called wave ____________________.

Question 52

Tidal ranges are lowest where the sea bottom slope is ____________________ in slope and the inlet is ____________________ in width,and are highest where the slope is ____________________ in slope and the inlet is ____________________ in width.

Question 53

A(n)____________________ is the location where land meets the sea;a(n)____________________ is that plus the land both seaward and landward of it.

Question 54

Large-scale surface water circulation systems in the oceans are known as ____________________.

Question 55

The average salinity of seawater can be expressed as ____________________ grams per kilogram of seawater,____________________ parts per thousand,and ____________________ percent.

Question 56

Spits and baymouth bars are formed due to ____________________ currents.

Question 57

The distance from one crest (or trough)to the next in a wave is the ____________________.

Question 58

Regularly-sized waves with long,rounded crests are known as ____________________.

Question 59

Tides that occur when the Sun and Moon are at right angles to one another and have wave-generating abilities that cancel each other out are ____________________ tides.

Question 60

A structure built perpendicular to shore to enlarge a beach or prevent erosion is a(n)____________________.

Question 61

The tiny shells of marine organisms create a marine sediment called

A)calcite
B)reefite
C)pelagic clay
D)ooze

Question 62

Water in waves is displaced from the circular orbits when:

A)waves enter progressively shallower water.
B)seas become swells.
C)waves reach great heights.
D)waves reach great lengths.
E)winds reach a critical velocity.

Question 63

Coriolis effect is the deflection of freely moving bodies,such as air or water molecules,that results from Earth's rotation.

Question 64

A deposit of unconsolidated sediment that extends landward from low tide to a change in topography or to where permanent vegetation begins is a:

A)spit.
B)tombolo.
C)barrier island.
D)beach.
E)baymouth bar.

Question 65

Sea level could change relative to a shoreline due to:

A)uplift of coastal regions.
B)subsidence of coastal regions.
C)rising sea level.
D)receding sea level.
E)all of the above

Question 66

The distance wave-producing winds blow over a continuous body of water is the:

A)wavelength.
B)trough.
C)height.
D)fetch.
E)velocity.

Question 67

Narrow surface currents that flow in the same general direction as the approaching waves are:

A)rip currents.
B)nearshore currents.
C)longshore currents.
D)upwelling currents.
E)refraction currents.

Question 68

Waves are oscillations of the water surface.

Question 69

In the open ocean salinity ranges from 32 to 37%.

Question 70

Rip currents commonly develop in regions where wave heights are highest.

Question 71

A coast that is straight and has marine terraces is a(n):

A)depositional coast.
B)erosional coast.
C)submergent coast.
D)emergent coast.
E)none of the above

Question 72

Currents that form from the collective movement of wave water refracted off a shoreline are:

A)rip currents.
B)nearshore currents.
C)longshore currents.
D)upwelling currents.
E)refraction currents.

Question 73

A beach with a small berm,coarser sediment,and offshore sand bars is a:

A)summer beach.
B)winter beach.
C)high-energy beach.
D)tide-dominated beach.
E)sediment-poor beach.

Question 74

The diameter of a water molecule orbit increases with depth until the wave reaches the seafloor.

Question 75

A beach with a wide berm,a gentle slope,and a smooth offshore profile is a:

A)summer beach.
B)winter beach.
C)high-energy beach.
D)tide-dominated beach.
E)sediment-poor beach.

Question 76

Vertical ocean circulation is the result of differences in what between adjacent water masses?

A)temperature
B)salinity
C)Coriolis effect
D)temperature and salinity

Question 77

A spit that connects an island to the mainland is a:

A)hook.
B)tombolo.
C)barrier island.
D)beach.
E)baymouth bar.

Question 78

Wave-cut platforms along northern coastlines of North America and the Great Lakes are exposed as the result of:

A)rising sea level.
B)sediment erosion.
C)sediment deposition.
D)isostatic rebound.
E)falling sea level.

Question 79

Spring tides are tides:

A)that result from the combined gravitational force of the aligned Moon and Sun.
B)that occur when the Sun and Moon are disposed at right angles to one another.
C)that occur in springtime when floodwaters are high.
D)with a relatively small range.
E)that are high only once per day.

Question 80

Individual sand grains move along a beach:

A)straight in the direction of the longshore current.
B)straight offshore.
C)in circles up and down the beach face but not horizontally down the beach.
D)in a zigzag pattern in the direction of longshore currents.
E)only during storms.