Coastal Hazards - Depositional and Erosional Coastal Landforms

Question 1

Coastlines evolve over time due to the ________ and ________ from breaking waves

Answer 1

erosion and deposition ; breaking waves

Question 2

This interaction between waves and a landmass can cause the shoreline to slowly move landward, a process referred to as _________

Answer 2

shoreline retreat

Question 3

Landward migration of a shoreline can also occur when there is a ____________, or when the land itself becomes ____________

Answer 3

rise in sea level ; lower due to subsidence

Question 4

Accumulations of sediment deposited by waves and longshore currents in the shoreline

Answer 4

Beaches

Question 5

beaches are deposited by:

Answer 5

waves and longshore currents

Question 6

t or f: sediments in beaches are well sorted

Answer 6

t

Question 7

4 main sources for beach sediment:

Answer 7

1. Local cliffs and promontories
2. The offshore zone
3. Calcareous sand and shell fragments from coral and mollusc debris
4. Local river bedload material

Question 8

are elongate deposits of sediment which parallel the
shore and are separated from the mainland by open water, lagoons, tidal mudflats, or saltwater marshes

Answer 8

barrier islands

Question 9

barrier island are ________ which ________ the shore

Answer 9

deposits of sediments ; parallel

Question 10

barrier islands are separated from the mainland by:

Answer 10

open water;
lagoons;
tidal mudflats;
saltwater marshes

Question 11

are coastal wetlands that form in intertidal areas where sediments have been deposited by tides or rivers

Answer 11

tidal flats

Question 12

is a shallow body of water protected from a larger body of water (usually the ocean) by sandbars, barrier islands, or coral reefs

Answer 12

lagoons

Question 13

Barrier islands result from the complex interaction between _____, _________, and _________

Answer 13

waves, sea level change, and sediment supply

Question 14

how does barrier islands form?

Answer 14

wave action causes deposition of sediments offshore forming sand bars, then eventually, enough sand accumulated to form a true island

Question 15

shoreline retreat is caused by

Answer 15

sea level rise and high erosional processes

Question 16

Tides move sand within inlets in an ________ manner, creating submerged ________ deltas.

Answer 16

oscillating manner ; ebb-tide

Question 17

Long narrow ridges of sand
and shingle which project
from the coastline into the
sea.

Answer 17

spit

Question 18

a beach that is tied to the
coast at one end and free
at the other

Answer 18

spit

Question 19

spit forms ________ to the longshore sediment drift and ____________ to prevailing wind direction

Answer 19

parallel ; perpendicular

Question 20

These are depositional
landforms by which an
island becomes attached to
the mainland by a spit or
bar.

Answer 20

tombolo

Question 21

tombolos are also know as

Answer 21

sandy isthmus

Question 22

how does tombolo form?

Answer 22

1. longshore drift transport material along the coast until the direction changes abruptly or bends
2. the materials are then deposited in the same direction seawards, forming a spit
3. the spit continues to grow and joins a nearby offshore island, then a tombolo is formed

Question 23

These are formed when
sand deposited off the
shore dries out and blown
out to the back of the
beach.

Answer 23

coastal dunes

Question 24

formation of coastal dunes usually need:

Answer 24

large tidal range
broad intertidal zones
large supply of sand

Question 25

Sites of mud and organic deposition, with quiet waters

Answer 25

lagoons, mudflats, marshes, and mangrove swamps

Question 26

t or f: lagoons, mudflats, marshes, and mangrove swamps are enclosed by barriers and spits

Answer 26

t

Question 27

lagoons, mudflats, marshes, and mangrove swamps are formed by combination of _________ and _______

Answer 27

river and coastal processes

Question 28

are wetlands that form as rivers empty their water and sediment into another body of water, such as an ocean, lake, or another river

Answer 28

deltas

Question 29

t or f: deltas cannot empty into land

Answer 29

F (it can but very rare)

Question 30

Deltas absorb runoff from both ________ and _______

Answer 30

floods (river) and storms (oceans, lake)

Question 31

t or f: Deltas also filter water as it slowly makes its way through the delta's distributary network. This can reduce the impact of pollution flowing from upstream

Answer 31

t

Question 32

two major ways to classify a delta:

Answer 32

1. influences/processes 2. shape

Question 33

four main types of deltas classified by the processes that control the built-up of silt

Answer 33

1. wave-dominated delta 2. tide-dominated delta 3. Gilbert deltas 4. Estuarine delta

Question 34

the movement of waves controls a delta's size and shape

Answer 34

wave-dominated delta

Question 35

usually form in areas with a large tidal range, or area between high tide and low tide.

Answer 35

tide-dominated delta

Question 36

these deltas are formed as rivers deposit large, coarse sediments, are usually confined to rivers emptying into freshwater lakes.

Answer 36

Gilbert deltas

Question 37

form as a river does not empty directly into the ocean, but instead forms a partly enclosed wetland that contains a brackish water habitat.

Answer 37

estuarine delta

Question 38

Deltas with this triangular or fan shape are called ________

Answer 38

arcuate (arc-like) deltas

Question 39

Stronger waves form a _________ , which is more pointed than the arcuate delta, and is tooth shaped.

Answer 39

cuspate delta

Question 40

A _________ has few, widely spaced distributaries, making it look like a bird's foot.

Answer 40

bird-foot delta

Question 41

The distributary network of an ________ is inland, while a single stream reaches the ocean or other body of water.

Answer 41

inverted delta

Question 42

a type of delta that emptied into a plain, and it extremely rare

Answer 42

inland deltas

Question 43

An __________ forms as a river develops a new channel, leaving the other to dry up or stagnate. This process is called _________

Answer 43

abandoned delta ; avulsion

Question 44

a natural process by which flow diverts out of an established river channel into a new permanent course on the adjacent floodplain abandoning the former channel.

Answer 44

avulsion

Question 45

a rock, sandbar, or other feature lying beneath the surface of the water

Answer 45

reefs

Question 46

reef lie how deep below the surface of water?

Answer 46

six fathoms or less beneath low water

Question 47

a fathom is equal to how many feet?

Answer 47

6

Question 48

best-known reefs

Answer 48

coral reefs

Question 49

coral reefs are developed through _______ processes dominated by _______ and __________

Answer 49

biotic ; corals; calcareous algae

Question 50

underwater structures made from calcium carbonate secreted by corals

Answer 50

coral reefs

Question 51

coral reefs are often called _____________

Answer 51

rainforests of the sea

Question 52

Reefs grow best in _____, ______, _______, _____and _______ waters.

Answer 52

shallow, clear, sunny, and agitated waters

Question 53

Most coral reefs were formed after the _________ when melting ice caused the sea level to rise and

Answer 53

last glacial period

Question 54

most coral reefs are ___________ years old

Answer 54

<10,000

Question 55

Coral reefs are found in the_____ away from __________, ___________ and as _________

Answer 55

deep sea ; continental shelves; around oceanic islands; atolls

Question 56

vast majority of oceanic islands that form coral reefs around are ________ in orgin

Answer 56

vocanic

Question 57

when did Charles Darwin set out his theory about the formation of atoll reefs

Answer 57

1842

Question 58

charles darwin theorized that ________ and _______ of the Earth's crust under the oceans formed atolls

Answer 58

uplift and subsidence

Question 59

3 stages of Atoll Formation (Darwin)

Answer 59

1. Fringing Reef 2. Barrier Reef 3. Atoll Reef

Question 60

how does atolls form?

Question 61

Darwin predicted that underneath each lagoons on atoll reefs would be

Answer 61

bed rock base (remains of the original volcano)

Question 62

Where the bottom is rising, fringing reefs can grow around the coast, but coral raised above sea level dies and becomes ________________.

Answer 62

white limestone

Question 63

t or f: Barrier reefs and atolls do not usually form complete circles, but are broken in places by storms.

Answer 63

t

Question 64

this type of reef is directly attached to a shore, or borders it with an intervening shallow channel or lagoon

Answer 64

fringing reef

Question 65

a reef separated from a mainland or island shore by a deep channel or lagoon

Answer 65

barrier reef

Question 66

this more or less circular or continuous barrier reef extends all the way around a lagoon without a central island.

Answer 66

atoll reef

Question 67

Marine erosion takes place mainly during ________ and as a result of ________

Answer 67

storms ; wave action

Question 68

The repetitive _________ slowly breaks the rocks apart and forms a______________ within the cliff face.

Answer 68

hydraulic action ; notch or undercut

Question 69

t or f: As the notch deepens the overhanging cliff becomes less stable, eventually causing the slope to fail in a mass wasting event

Answer 69

t

Question 70

In some instances the hydraulic pressure from crashing waves will slowly bore a hole through a cliff face, forming a____________

Answer 70

sea arch

Question 71

are points of land that jut seaward and areas where waves first make contact with land. This causes waves to refract

Answer 71

headlands

Question 72

observed where a more resistant portion of the rock remains in the surf, separated from the retreating cliff

Answer 72

sea stacks

Question 73

Column of rock standing in the water off a beach

Answer 73

chimney

Question 74

where wave erosion has hollowed out a line of weakness in otherwise resistant promontory

Answer 74

sea arch

Question 75

are places where waves first make contact with land and with the greatest amount of energy

Answer 75

headlands

Question 76

t or f: in headlands, the energy is high and erosion rate is high

Answer 76

t

Question 77

As the waves refract around both sides of the headlands, eroded material is transported into ________ via ____________ where it is deposited, forming ___________

Answer 77

coves ; longshore current ; isolated beaches

Question 78

how does an active shoreline transitions into a passive shorelines?

Answer 78

Once tectonic activity ceases, irregular coastlines slowly evolve into passive shorelines with more low lying terrain and broad, straight beaches. Initially waves break on headlands, forming longshore current cells that transport eroded material into coves. As the headlands become smaller, the beaches and longshore cells will eventually merge, forming relatively straight sections of beach where sediment is transported parallel to shore.

Question 79

are gently sloping platform of rocks that extend seaward in to a steep drop off.

Answer 79

shore platforms

Question 80

what are the dominant influences on coastal landforms?

Answer 80

1. type of continental margin 2. relief, structure, and lithology 3. climatic influences 4. rates of erosion 5. sea level

Question 81

Edges of actively diverging plates are _________ and ___________, and consequently tend to be relatively straight with few __________

Answer 81

rifted ; block faulted ; embayments

Question 82

what type of continental boundaries forms passive margins with continental shelves?

Answer 82

Divergent boundaries

Question 83

t or f: passive continental margins have thicker sedimentary carapce

Answer 83

t

Question 84

active continental margin is also called

Answer 84

Pacific Type Boundary

Question 85

pacific type boundaries are characterized by islands such as

Answer 85

Philippines, Indonesia, and Japan

Question 86

t or f: pacific type boundaries exhibit continental shelves

Answer 86

F (absent and continental shelf)

Question 87

in pacific type boundary, structural trend_____________ to the line of convergence

Answer 87

parallel

Question 88

t or f: pacific type boundary have deep offshore trenches and a line of a mountainous arc

Answer 88

t

Question 89

passive continental margin is also called

Answer 89

Atlantic-type Margins

Question 90

atlantic-type margins may have _______ and ______ continental shelves

Answer 90

shallow and broad

Question 91

Resistant rocks and or tectonically uplifted blocks form_________with ____________

Answer 91

uplands ; cliffed coastal margins

Question 92

competent rocks have _________ relief

Answer 92

high

Question 93

soft rocks exhibit ________ relief

Answer 93

low

Question 94

The energy available for coastal processes is partially controlled by

Answer 94

1. wave height 2. wind speed direction 3. wind speed duration

Question 95

High energy coasts tend to have ____________, _____________

Answer 95

rocky beaches ; severely eroded upland coasts

Question 96

Low energy coasts tend to have _________, _______, or ______

Answer 96

deltas, salt marshes, mangrove swamps

Question 97

coasts between latitudes of ____________ and _______ facing coasts in the ______________ generally have high storm induced _________

Answer 97

45 to 60 degrees ; east; tradewind belts; swells

Question 98

energy along waves is influenced by

Answer 98

wind

Question 99

t or f: high winds = greater wave heights

Answer 99

t

Question 100

t or f: coastal zone is a rapid zone of change

Answer 100

t

Question 101

t or f: coasts may advance or retreat in a yearly basis

Answer 101

t

Question 102

Coastal positions have changed almost constantly through constant cycle of __________ and _____________

Answer 102

glaciation and melting

Question 103

Present day sea levels can be related into an environment of _______

Answer 103

warm period