Question 1

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

Accepted Answer

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?

Accepted Answer

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?

Accepted Answer

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?

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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?

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Question 6

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

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Question 7

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

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Question 8

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

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Question 9

Describe how a coral atoll forms.

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Question 10

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

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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?

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Question 12

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

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Question 13

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

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Question 14

What causes a wave to break when it reaches shore?

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Question 15

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

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Question 16

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

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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.

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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?

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Question 19

Describe how waves are generated.

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Question 20

Why do waves bend or refract as they approach shorelines?

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Quiz 15: Oceans, Shorelines, and Shoreline Processes