Deck 16: Oceans, Shorelines, and Shoreline Processes

Question 1

What provides most of the sediment of a beach?

Answer 1

Longshore currents moving sediment in the nearshore zone.

Question 2

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.

Answer 2

Rising sea levels cause erosion,shoreward migration of barrier islands,and even submergence of barrier islands.This is of concern because so many expensive properties are located on barrier islands,and barrier islands protect the mainland from erosion and flooding and are a part of the natural coastal wetland habitat.

Question 3

If you were caught in a rip current,how would you attempt to reach shore?

Answer 3

Swim parallel to shore a short distance before swimming toward shore.

Question 4

Why are waves in ponds and lakes smaller than those in oceans?

Question 5

What determines the characteristics of beaches?

Question 6

Why do waves bend or refract as they approach shorelines?

Question 7

How are most waves generated?

Question 8

List the primary ways that oceanographers learn about the seafloor and briefly explain each.

Question 9

How does wave behavior on lakes differ from that of seas?

Question 10

What path do water particles in a wave ideally follow?

Question 11

In what direction do longshore currents flow?

Question 12

Briefly explain how the functions and locations of groins and jetties differ.

Question 13

Briefly explain how longshore and rip currents are related.

Question 14

Explain how a seismic profile is created and what types of information it provides.

Question 15

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 16

What three factors interact to create rip currents?

Question 17

What is wave base,and how deep is it?

Question 18

What is the difference between a fringing reef and a barrier reef?

Question 19

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

Question 20

What are some depositional features of shorelines?

Question 21

Briefly explain how a tombolo forms.

Question 22

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

Question 23

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 24

How are sea cliffs eroded?

Question 25

Under what conditions do barrier islands form?

Question 26

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

Question 27

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

Question 28

Shoreline erosion is common in many parts of the world,in part because sea level is ____________________.

Question 29

The apparent deflection of a moving object from its anticipated course resulting from Earth's rotation is called _______ _______.

Question 30

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

Question 31

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

Question 32

What are two models that may explain the formation of barrier islands?

Question 33

How do marine terraces form?

Question 34

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

Question 35

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

Question 36

What is one major problem for residents on barrier islands?

Question 37

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

Question 38

What are the most important reasons for changes in beach profiles?

Question 39

Why must shoreline government officials understand the geologic processes of shorelines?

Question 40

A(n)____________________ is the location where land meets the sea; a(n)____________________ is the same,in addition to the land both seaward and landward of it.

Question 41

A spit that has lengthened until it closes the mouth of a bay is a(n)____________________.

Question 42

The zone that extends to just beyond where the waves break is called the ____________________ zone.

Question 43

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

Question 44

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

Question 45

The two important types of near shore currents are ____________________ currents and ____________________ currents.

Question 46

Salinity of seawater is a measure of

A) the total sodium and chloride.
B) the total quantity of dissolved solids.
C) the trace elements.
D) the sodium and chlorine.

Question 47

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 48

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

Question 49

The aphotic zone is

A) a thin layer, about 100 m or less.
B) organic substances rain down from the photic zone.
C) where plants receive enough light to photosynthesize.
D) all of these.

Question 50

Most of the chemical elements in seawater come from

A) outgassing.
B) ocean life.
C) the seafloor.
D) the continents.

Question 51

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

Question 52

Scientists today calculate the depth to the seafloor using

A) the time it takes for sound waves to travel from a ship to the seafloor and back.
B) seismic waves that reflect from the seafloor.
C) a very long line with a weight attached.
D) trips to the seafloor in modern submersibles.

Question 53

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

Question 54

The ____________________ of a wave is the time necessary for two successive ____________________ or ____________________ to pass.

Question 55

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 56

When wave base is reached,wave velocity and wave _______ decrease,while wave _______ increases.

Question 57

Geologic evidence suggests that oceans were present by at least

A) 4.6 billion years ago.
B) 3.5 billion years ago.
C) 4.6 million years ago.
D) 1.5 billion years ago.

Question 58

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

Question 59

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

Question 60

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

Question 61

Vertical ocean circulation,in which water moves from deep to shallow,is called

A) surface currents.
B) deep currents.
C) downwelling.
D) upwelling.

Question 62

By definition,beaches are composed of sand.

Question 63

Rip currents tend to develop over regions where the sea/lake floor is slightly deeper.

Question 64

Wave size depends entirely on wind velocity and duration.

Question 65

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 66

The amount of oil from U.S.production that comes from the Gulf of Mexico is

A) 10%
B) 30%
C) 65%
D) 100%

Question 67

Sediment is lost from the nearshore zone by ____.

A) wind erosion
B) deposition into submarine canyons
C) offshore transport
D) deposition into submarine canyons and offshore transport
E) All of these

Question 68

What is a spit that connects an island to the mainland called?

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

Question 69

A deposit of unconsolidated sediment that extends landward from low tide to a change in topography or to where permanent vegetation begins is a(n)____.

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

Question 70

Winter beach profiles can actually develop during any season.

Question 71

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

Question 72

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 73

What are narrow surface currents that flow in the same general direction as the approaching waves?

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

Question 74

The saltiness of seawater has been a state of dynamic equilibrium for at least 1.5 billion years.

Question 75

Ocean currents move in the direction of local winds.

Question 76

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

Question 77

What is a coast that is straight and has marine terraces called?

A) depositional coast
B) erosional coast
C) submergent coast
D) emergent coast
E) none of these

Question 78

A beach with a small berm,coarser sediment,and offshore sand bars is a(n)____.

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

Question 79

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 80

Nearly all beach sand is quartz.