GEOG CH.15

Winters typically produce larger and/or more frequent storms that affect beaches. What overall change happens to a beach during a winter with frequent, large storms?

The beach becomes rocky as sand is moved offshore.

Which of the following statements are true regarding tides?

The difference between high and low ties is usually between 1 to 3 meters. In most places, high and low tide occur every 12 hours and 25 minutes. They are cyclic changes in the height of the sea surface.

The amount of sediment available to a shoreline system is calculated by a sediment____________

budget

An decrease in ocean temperature results in a relatively small_______________in sea level. (Consider all this water is above 4°C.)

decrease

True or false: Below the wave base, there is no wave action (from surface waves).

True

Describe the sediments that are reworked in the surf zone by matching them to relative amount of time they are reworked.

Large, angular rock pieces - The least amount of time Flattened, smooth pebbles - A moderate amount of time Sand - The most amount of time

The highest tides in the world are in the ______ where the tidal range is as much as 16 m.

Bay of Fundy, in Nova Scotia,

The features described are either indicative of submergent or emergent coasts. Choose those for submergent coasts.

Coastal dunes become bars or barrier islands. Estuaries create an irregular coastline.

Waves on the surface of a body of water are usually generated by ___________.

Wind

Sea cliffs, wave-cut platforms, and sea stacks and arches result from ______ coast; spits, baymouth bars, and barrier islands result from ______ coast.

erosion at an uplifted; deposition at a submerged

The glacial loading of continental crust near a coastline will cause the crust to downwarp and a subsequent ______ in sea level.

increase

With the Hurricanes Irene, Isaac, and Sandy, ______.

some sandbars became completely submerged the inundation regime was breached and homes were destroyed

Explain the development of a sea stack by placing the statements in order. Begin with the earliest occurrence at the top and end with the development of a sea stack at the bottom.

1. A promontory extends out into the sea2. Wave action begins rot erode at the weaker parts of the rock on the promontory3. A sea cave is formed, as rock behind the tip of the promontory is eroded faster than the tip4. Continued erosion collapses the roof of the sea cave, leaving a passage behind the tip of the promontory5. A sea stack is created that was once the tip of the promontory

What are possible causes of sediment slumping offshore of the beach, as in the image?

An earthquake may have disrupted the sediment. Sediment may have been physically disturbed by wave action. The sea bottom may be too steep to hold the sediment

Sediment along the beach and offshore will slump if the slope is too______or if it is______during an earthquake.

Blank 1: steep Blank 2: shaken or disturbed

Match each type of tide to the correct description.

Flood tide - A tide that is in the process of rising and approaching high tide Ebb tide - A tide that is in the process of falling and approaching low tide

What is swell?

Waves moving independently of wind

When weight is added to a landmass, ______ occurs, and the land surface can downwarp. When weight is removed from a landmass, ______ occurs, resulting in the elevation of the region flexing back upward with isostatic rebound.

loading; unloading

If there is a large amount of continental landmass near the poles, then sea level will be relatively ______.

low

A sea cave represents the ______ stage in the creation of a sea stack.

intermediate

Most surface ocean waves are caused by ______.

wind blowing across the top of the water

If two successive wave crests are 30 m apart, what is the approximate depth of the wave base?

15 m

Match the letter on the ocean wave diagram with the corresponding term.

A - Wave height B - Wavelength C - Depth of wave base = wavelength/2 D - Trough Crest

Match the labeled feature in the image with its name.

A-Spit B-Baymouth bar C-Barrier island

Of the hazards listed below associated with hurricanes, which is the one that commonly causes the most damage?

Storm surge

Which of the following are observed in an overwash situation?

The seaward side of a barrier island loses its beach, while the backside of the island grows.

Fast seafloor spreading creates a wide mid-ocean ridge, which results in ______.

an increase in sea level less room for seawater

What are some hazards that exist along coastlines?

Storm surge Strong winds and rain; flooding Wave erosion—especially during storms

Based on what you know about the causes of high and low tides, match the type of tide that would be present with the individual locations in the situation depicted. Assume the Sun is to the left of the illustration.

High tide - A & C Low tide - B & D

Which of the following statements are true regarding the cause of high and low tides?

High tides occur on the side of Earth facing away from the Moon, as water bulges out due to a decreased force of gravity from the Moon. High tides occur on the side of Earth facing the Moon due to the pull of gravity on the oceans.

The ______ is the primary cause of tides.

Moon

Based on the lidar images of elevations (showing coastal Alabama pre-Hurricane Ivan, post-Hurricane Ivan, and post-Hurricane Katrina), how has lidar data helped scientists understand this shoreline (high "boxes" represent houses)?

-Demonstrates that this coastline is at high risk for storm damage -Shows large changes in erosion and deposition of sediment in different areas along the coast

Which of the following methods could be used to return a shoreline system to its natural state?

Remove dams on rivers that supply sand. Restore wetlands and barrier islands.

Rank the four regimes of beach erosion by placing the one with the lowest threat of erosion at the top and the one with the greatest threat at the bottom.

1. Swash regime 2. Collision regime. 3. Overwash regime 4. Inundation regime

Repeated lidar surveys can be used to document the effects of hurricanes on barrier islands because ______.

erosion can be measured houses can be located and monitored pre- and post-event sedimentation can be measured

Rank the following processes in order from top to bottom to describe the formation of a spit, at the top, followed by a baymouth bar, and finally a barrier island at the bottom.

1. Waves and longshore currents move sediment along the coast, building up a long, low mound of sediment. 2. A low mound of sediment lengthens in the direction of the prevailing longshore current, starting to cut across a bay. 3. A low mound of sediment becomes long enough that it cuts off a bay. 4. Sea level rises and submerged, low-lying sediment mounds are broken up into individual islands.

Promontories and bays influence and are affected by wave action differently. Choose the description that apply to promontories rather than bays.

A vulnerable projection of land into the water; wave action is focused here, causing high levels of erosion. Waves may refract around this feature, causing waves to strike it from all sides and increase erosion.

Why do initially straight water waves generally refract (bend) as they approach a shoreline?

As waves approach the shore, the segments closest to the shore slow down relative to those farther out.

Match the common landforms of an idealized beach profile to their correct description.

Berms - Found in the backshore and appear as nearly flat platforms Dunes - Generally found above the water line and consist of sand deposits Longshore bars - A gently sloping mound in the inshore region

Moving from a low to a high tide, a rising tide is also known as a(n) _______ tide, whereas a tide that is moving from high to low is falling and is known as a(n) _______ tide.

Blank 1: flood Blank 2: ebb

Which of the following impacts on coastlines are commonly associated with hurricanes?

Extreme erosion Storm surge

True or false: The only process responsible for the movement of sediment along a shoreline is wave action.

False

Which of the following are true of LIDAR used to monitor coastlines?

It employs a laser beam directed out of an airplane. Measurements over time may help show areas of erosion and deposition along shores. It is used to collect information about elevation.

This groin was installed in order to protect the shore; what is happening to the sand on the downcurrent side?

It is being eroded.

Match the geologic feature with whether its presence marks a greater risk or lesser risk for hazards along a coastline and the associated reason behind that risk.

Large dunes: Lesser risk (particularly for those stabilized by vegetation); lowers the risk of erosion and risk from inland storm surge.Sandbars and reefs: Lesser risk; protection of a coast from wave action by these barriers.Gentle slope of the land adjacent to shore: Greater risk; allows the sea to wash farther into the land, potentially causing more flooding by storm surges.Narrow beach: Greater risk; allows erosion during storms, affecting structures sitting near the coastline.

When waves approach the shore at the angle depicted on the diagram, in what direction will the sand be transported?

Laterally to the right

The__________ current moves sand parallel to the coast.

Longshore

Which of the following are true regarding wind action along a shoreline?

Low- to moderate-strength wind cannot dislodge sand that is wet. Wind is more effective at moving sediment above the shoreline where the sand is dry and loose. Wind is common along shorelines.

Which of the following is true regarding the erosion impacts that occurred as a result of Hurricanes Irene, Isaac, and Sandy?

Many homes along the coast, which were at the lowest elevations, were destroyed by storm surge and subsequent erosion.

Match the factor with how it may affect sea level.

Melting of glaciers and ice sheets: Large volumes of water are released back into the ocean, sea level rises.Fast rates of seafloor spreading: Mid-ocean ridges become broader and ocean water is displaced out of ocean basins; sea level rises.Cooler ocean temperatures: Water in the oceans will slightly contract; sea level drops.Position of more continents near the poles: Glaciation becomes widespread; sea level drops. Loading and unloading: Continental ice sheets cause elevations to decrease; the land "bounces" back up when the glacier recedes.

Which of the following are reasons that a promontory will be more vulnerable to wave erosion than a bay?

More powerful waves focus their energy at a promontory than a bay. A promontory will receive more wave action than a bay. Waves bend around a promontory and strike it from both sides.

Which of the following geologic features increase the risk of shoreline hazards?

Narrow-width beaches Low river valley Gentle sloping shoreline

Select all of the following areas that are known as locations for large reefs.

Northeastern Australia New Caledonia (islands east of Australia and Melanesia) Polynesia Philippines Caribbean (The Bahamas)

____________is a process whereby materials are typically transported from the side of an island facing the sea (as opposed to the side facing the mainland), to the side away from the sea, as is often seen in barrier islands where the backside of the island grows.

Overwash

Changes in sea level may be caused by which of the following?

Rates of seafloor spreading Increases in ocean temperatures Amount of continental glaciation Position of the continents

___________are primarily shallow, submarine features made up of living marine organisms such as coral, sponges, and shellfish.

Reefs

Which of the following are true for reefs?

Reefs are generally found in shallow water. Reefs are primarily built by colonies of living marine organisms.

Which of the following are common processes that may affect shorelines?

Shallow water currents Waves and tides Sediment transport by rivers Fine sediment carried by wind

Select all of the following that are true regarding rip currents.

Rip currents tend to disrupt the normal wave pattern. Rip currents cause many drownings each year. Rip currents are a particularly strong form of backwash.

Match the shoreline appearance with the typical setting/circumstances for its creation.

Rocky coast - Coastal land is made of hard rock that resists erosion. Coastal outline of narrow inlets and bays - A rise in relative sea level flooded river valleys along the submerging coast. Gentle slopes and rounded hills - Land materials are soft and easily eroded; available sediment is fine grained. Large amounts of soil and vegetation - A wet climate exists along the coast.

Match the engineered structure with the negative consequences on the coastline.

Seawalls - Beach sediments are eroded seaward of this structure. Jetties - Waves are focused on adjacent stretches of coast, causing erosion. Groins - The longshore drift is blocked, causing erosion down current.

What approaches are used to address shoreline erosion problems?

Seawalls and breakwaters Not building along coasts Beach nourishment Jetties and groins

Match the features with how they may address shoreline problems.

Seawalls:Built along the shore in an attempt to "armor" the coast against erosion, they commonly result in the loss of beach in front of the feature. Jetties:Jutting out into the water to protect a bay, harbor, or beach, they usually are built in pairs to protect a shipping channel. Groins:Placed perpendicular to the shore to influence lateral transport of sand by longshore currents, they often trap sand on one side and cause erosion on the other. Breakwaters:Built parallel to the shore, in the water near the brunt of waves and currents, they can protect the shoreline from erosion.

Which factors may directly influence the strength of wave action (and therefore the strength of erosion and transportation/deposition of sediment) striking a coast?

Size and intensity of storms Orientation of the coastline Slope of the adjacent seafloor

How do waves erode material from the shoreline?

Smashing together loose pieces of rock and making large, angular rocks become smaller, rounded ones Wearing away of bedrock with the crashing and grinding of water and sediment Breaking directly on a rocky coast and swirling away loose pieces of bedrock

Which of the following occurred in northeastern Canada as a result of loading and unloading?

Some areas have experienced more than 100 m of uplift, from isostatic rebound, over the last 6,000 years. The weight of continental ice sheets, occurring on and off over the last 2 million years, depressed some portions of the North American plate.

Match each regime to the correct description of coastal erosion that occurs there.

Swash regime - Little permanent erosion occurs here. Collision regime - Erosion here occurs at the base of the dune. Overwash regime - Erosion here may involve the entire dune and often transports sand toward the land. Inundation regime - Here the entire dune is submerged, and large quantities of sand are typically transported to land, permanently moving the beach.

______ are waves that exist independently of winds or storms.

Swells

Continental glaciers are usually thicker in their center. Looking at this map of crustal rebound in Canada, what does it imply about the ice sheet that covered Canada in the Pleistocene?

There were two centers of flow.

Why are some coastlines sheltered from strong waves?

They form behind a barrier reef. They are in a bay. They are situated behind an island.

Which of the following are true for wave-cut platforms?

They form relatively flat terraces on the land. The surface of the platforms may contain marine fossils and wave-rounded stones. They form within the surf zone along rocky shorelines.

Match the time sequences on the image (corresponding to hypothetical locations of the Moon relative to the Earth and Sun) with the type of tide coastal areas on Earth would experience.

Time 1 - The area would experience a strong spring tide. Time 2 - The area would experience a weak spring tide. Time 3 - The area would experience a neap tide.

In which of the following environments are coral reefs most likely to form?

Warm, clear, shallow seawater

Which of the following will occur as a water wave continues to move to the right in the diagram shown?

Water at point B will move in a smaller diameter circular pattern than water at point A. Water at point C will hardly move at all. Water at point A will move in a clockwise circular pattern.

Which of the following areas are general places where large reefs are located?

Waters between latitudes of 30° north and 30° south Tropical waters Ocean waters near the equator

Match the ocean wave term with its appropriate description.

Wave crest: The highest part of a wave.Wave trough: The lowest part of a wave.Wavelength: The horizontal distance between two wave crests.Wave height: The vertical distance between the wave crest and the wave trough.

Match the shoreline hazard with its best description.

Wave damage - It occurs mostly during hurricanes and storms; erosion of land and hillsides collapses slopes and buildings into the water. Storm surge -Water may pile up in front of an approaching weather system, inundating low-lying areas along the coast. Strong winds - Communities along a coast lack a windbreak between them and the open water; damage may be severe. Rainfall-related flooding - Many coastal areas are low-lying and have flat elevations, and so structures are prone to damage.

An increase in continental glaciation causes a(n)______________in sea level.

decrease

The coastal sediments of Cape Cod that have been reworked into spits, bars, barrier islands originally were deposited by

glaciers

Geographers use______________to collect large amounts of very accurate data about coastlines by using lasers to determine elevations of different features.

lidar

Slow seafloor spreading creates a narrow mid-ocean ridge, which results in ______.

more room for seawater a decrease in sea level

A shoreline can gain or lose sand. The amount of sediment available to a shoreline system is the ______.

sediment budget

A worldwide increase in sea level commonly reflects the ______ of continental glaciers.

shrinking

A(n) ______________ coast forms when it is inundated by shallow seas, and a(n) _____________________ coast forms when a formerly submerged part of the continental shelf is exposed as dry land.

submergent emergent

Coasts that form where the land has been inundated by the sea, due to a relative rise in sea level, are ______ coasts; coasts that form where the land experiences a relative drop in sea level are ______ coasts.

submergent; emergent

Order the systematic changes that occur in waves as they approach the shore, ending with the wave breaking at the bottom. Drag and drop application.

1. Water shears on the bottom when the depth is shallower than the wave base, as the waves approach the shore2. Waves slow down3. Wave crests bunch up and become steep (wave height increase and wavelength decreases)4. Wave crests topple over, and the wave breaks in the surf zone

If two successive wave troughs are 50 m apart, what is the approximate depth of the wave base?

25 m

Which of the two globes, A or B, with variable continental positions, will likely have a lower global sea level? (Assume the geographic poles are located at the top and bottom of each globe.)

A

Match the features associated with a relative sea level rise, in the image, with their descriptions.

A - An irregular, branching estuary has been created where a river valley once existed. B - A new island has formed out of what was originally a hill. C - Barrier islands have become totally submerged by rising seas.

Match the image letter with the correct type of reef depicted.

A - Barrier reef B - Atoll C - Fringing reef

Match the image with its appropriate description, related to tide level.

A - High tide is shown, with the ocean at its highest point relative to land. B - Average sea level is shown, with an intermediate ocean height, occurring between high and low tide. C - Low tide is shown, with the ocean at its lowest level on a shoreline.

Match the letters on the image to the correct landform found in an idealized beach profile.

A - Longshore bar B - Berm C - Dune D - Beach face

Match the coastal feature in the image with its description and how it affects the shoreline.

A - Rocky coastline is created by bedrock that is resistant to erosion. B - Storms alter the strength of waves, wind, and rainfall amount. Storms may cause greater erosion and move larger clasts of sediment along the shore. C - Sediment from rivers produces deposition and accumulation of sediment along the coast. D - Orientation of the coast creates a sheltered area that receives less wave action. E - A steeply sloped seafloor causes large waves to break directly against the shore. High levels of erosion occur.

Match each lettered image to the correct stage of atoll formation represented.

A - Stage 3 B - Stage 2 C - Stage 1

Which of the following statements are true of the landforms of Cape Cod, Massachusetts?

A large spit curves and projects toward the north. Barrier islands and smaller spits are present. Much of the sediment making up Cape Cod was originally deposited by glaciers, but then flooded and reworked as global sea level rose.

An emergent coastline's features commonly include which of the following?

A wave-cut platform A wave-cut notch Exposed coral reefs

Match the different types of reefs to the best description.

Barrier reefs - Occur parallel to the continents, offshore from the main coastline Fringing reefs - Occur attached to a coast or just offshore, surrounding an island Atolls - Occur as curved reefs that enclose a shallow, inner lagoon, often forming where an island, flanked by coral, has sunk

A ___________ tide is a high or low tide that is more extreme than usual, but a _________ tide is weaker than usual.

Blank 1: spring Blank 2: neap

Which of the following are true regarding the wave base?

No wave action occurs below this point. The depth to the wave base is about half the wavelength.

Match the following components of the littoral zone to their best description.

Offshore - Consists of a deeper water zone. Inshore or swash zone - Permanently submerged by shallow water where waves break Foreshore - Submerged during high tides but exposed during low tides Backshore - The highest part of the beach and only seldom covered by water

What direction, relative to the beach, does a longshore current move?

Parallel

__________currents occur when the backwash moves perpendicular to the shore, moving water very quickly and dangerously back to the ocean.

Rip

Which of the following are common occurrences that alter sediments within the surf zone?

Rocks become smooth and flattened. Angular rocks are rounded as their corners are knocked off. Sand forms from broken rock particles.

Match the shoreline feature with the description of how it is formed via wave erosion.

Rounded sediment: Waves smash together loose rock, causing angular corners to wear away. Wave-cut notch: Crashing water and sediment water wear away at bedrock along a rocky shoreline in the same place over time.Wave-cut platform: Waves wash sediment back and forth across the sea bottom and smooth off the underlying bedrock.Angular sediment: Waves break directly on the coast and swirl away loose, broken pieces of bedrock.

What happens to sediment along a shore during a storm?

Sediment deposition occurs farther up the beach than normal. Large waves erode sand. Sand moves out to sea.

Match the type of tide (spring or neap) with the correct description.

Spring tide geometry - Created when the Earth-Moon-Sun system is in alignment Spring tide timing - Occurs at times of the new moon and full moon Neap tide geometry - Created when the Moon is at a right angle from the Sun in the Earth-Moon-Sun system Neap tide timing - Occurs at times of the first-quarter moon and third-quarter moon

Match each step of atoll formation to the correct stage.

Stage 1: A volcanic island forms through a series of eruptions, creating a shoreline for the building of a fringing reef.Stage 2: The volcanic island cools and begins to sink, but corals continue to grow upward, as the land subsides, created a barrier reef.Stage 3: The volcanic island sinks below the ocean surface, but corals continue to grow upward around a shallow lagoon.

If a rubber duck were floating on the surface of the water in the image, at the point marked "X," and a series of waves were moving toward the right, how would the duck's movements best be described?

The duck will follow a small, clockwise circular path, going up and forward and then down and back, as the wave passes.

Which of the following are factors that affect whether a shoreline gains or loses sediment over time?

The existence or absence of nearby reefs and barrier islands The degree of erosion by waves The dynamics of longshore currents The amount of runoff

What causes tides?

The gravity of the Moon and a small influence from the Sun

Which of the following contribute to the breaking of waves as they move into shallow water?

The lower parts of the waves shear against the bottom, as the wave depths becomes shallower than the wave bases. The waves becomes too high and steep to support themselves. The wave heights increase, as the wavelengths decrease. The velocity of the waves slow, as they move into the shore.

Which of the following statements regarding coastal zones is true?

The width of the strip of land and water within the coastal zone varies with the type of coast.

The features described are either indicative of submergent or emergent coasts. Choose those for emergent coasts.

Wave cut notches create topographic steps. Old coral reefs are exposed on land.

Match the shoreline feature with the best description.

Wave-cut platform - Erosion at sea level bevels off bedrock and forms a flat surface that may be covered by water at high tide and fully exposed at low tide. Sea arch - Erosion cuts through a small promontory jutting out to sea. Sandbar - It is formed as waves and longshore currents move sediment, and it may shift positions but is typically submerged. Marine terrace - It is formed by a wave-cut platform that is uplifted above sea level.

Match the process with its description of how it affects shorelines.

Waves - Mostly generated by wind, they erode rock and move and deposit sediment. Rivers - They are an important contributor of sediment from the land side and may deposit sediment in the form of a delta. Winds - They move fine material on a beach, and transported sediment may form dunes. Faulting/tectonic activities - Over time, they may raise or lower parts of a coast relative to sea level, causing either emergence or submergence of the coast. Currents - They may move either shallow or deeper-level water, and they transport sediment along a coast.

Why does sand move laterally along the coast (as in the image)?

Waves approach the coastline at an angle. Incoming waves move sand alternately inshore at an angle, and then perpendicular to the beach, back offshore.

In which of the following situations would a beach generally see an increase in its sediment budget?

Waves erode sediment from offshore reefs and sandbars. Rivers and deltas are present. Large amounts of runoff from land occurs.

The area that includes the shoreline and a strip of adjacent land and water is the ______.

coastal zone

This image shows a coastline that ______.

has experienced a rise in relative sea level and is considered a submergent coast

The coastline in the image ______.

is an emergent coast has undergone a relative fall in sea level shows an example of a marine terrace

As a wave approaches the shore at an angle and begins to encounter the bottom, it refracts, and the side closest to the shore ______.

is slowed more than the segment in deeper water

Rank the following components of the littoral zone from farthest out to sea at the top to closest to land at the bottom.

offshore, inshore or wash zone, foreshore, backshore

Wave-cut ______________form within the surf zone along many rocky shorelines and appear as relatively flat terraces on the land.

platforms

The Bay of Fundy in Nova Scotia is famous for having the largest

tidal

Coral reefs form in ______.

water that contains minimal amounts of suspended sediment because too much sediment blocks light needed by the corals shallow water because corals need sunlight for photosynthesis