Chapter 20 Shorelines

Front 1

trough

Back 1

lowest point on a wave

Front 2

crest

Back 2

highest point on a wave

Front 3

wave height

Back 3

the vertical distance from trough to crest

Front 4

wavelength

Back 4

the horizontal distance between 2 successive troughs or 2 successive crests

Front 5

wave period

Back 5

the time interval between the passage of two successive troughs or two successive crests

Front 6

wave height, wave period, and wavelength all depend on these three factors

Back 6

the wind speed, the length of time the wind has blown, and the distance the wind has blown across open waters

Front 7

beach drift

Back 7

the transport of sediment in a zigzag pattern along the beach caused by the uprush of water from obliquely breaking waves

Front 8

longshore current

Back 8

a near shore current flowing parallel to the shore

Front 9

spit

Back 9

elongated ridge of sand that projects from land into the mouth of an adjacent bay

Front 10

interface

Back 10

a common boundary where different parts of a system interact

Front 11

shoreline

Back 11

the line that marks the contact between land and sea

Front 12

shore

Back 12

the area that extends between the lowest tide level and the highest elevation on land that is affected by storm waves

Front 13

coast

Back 13

extends inland from the shore as far as ocean-related features can be found (where the shore ends onward)

Front 14

coastline

Back 14

the coast's seaward edge (where the coast starts and where the shore ends)

Front 15

the shore is divided into 2 categories

Back 15

the foreshore and the backshore

Front 16

foreshore

Back 16

the area that is exposed when the tide is out (low tide) and the submerged when the tide is in (high tide).

Front 17

backshore

Back 17

landward of the high-tide shoreline or the part past the high-tide shoreline. (usually dry only being affected by waves during storms)

Front 18

nearshore zone

Back 18

lies between the low-tide shoreline and the line where waves break at low tide

Front 19

offshore zone

Back 19

seaward of the nearshore zone (anywhere past the nearshore zone)

Front 20

beach

Back 20

an accumulation of sediment (not just sand) found along the landward margin of an ocean or a lake

Front 21

berms

Back 21

relatively flat platforms often composed of sand that are adjacent to coastal dunes or cliffs and marked by a change in slope at the seaward edge

Front 22

beach face

Back 22

the wet sloping surface that extends from the berm to the shoreline (wet hard-packed sand)

Front 23

fetch

Back 23

distance that the wind has traveled across open waters

Front 24

surf

Back 24

the turbulent water created by breaking waves

Front 25

describe the motion of a floating object as a wave passes

Back 25

the motion of a floating object would be a circular motion

Front 26

as a wave travels the water passes the energy along by moving in a circle this is called

Back 26

circular orbital motion (occurs under water as well)

Front 27

wave base

Back 27

the point at which circular orbital motion under water diminishes

Front 28

When the front of a wave is too steep to support itself and the front of the wave collapses is called a

Back 28

break

Front 29

the water from a collapsing breaker is known as a

Back 29

swash

Front 30

backwash

Back 30

the water that (expanded from the swash [swashs are formed from a collapsing breaker or wave) flows back down the beach toward the surf zone

Front 31

How do a wave's speed, wavelength, and height change as it moves into shallow water and breaks?

Back 31

The speed of the wave slows, the wavelength shortens, and the height increases

Front 32

abrasion

Back 32

The grinding and scraping of a rock surface by the friction and impact of rock particles carried by water (waves)

Front 33

wave refaction

Back 33

the bending of waves

Front 34

rip currents

Back 34

concentrated movements of water that flow in the opposite direction of breaking waves

Front 35

What is the effect of wave refraction along an irregular coastline

Back 35

beach drift (longshore transport or the transport of sediment along the beach in the direction of the waves)

Front 36

Describe the two processes that contribute to longshore transport

Back 36

longshore currents and beach drift

Front 37

features that originate primarily because of erosion are called

Back 37

erosional features

Front 38

accumulations of sediment are called

Back 38

depositional features

Front 39

Name 5 erosional features

Back 39

Wave-cut cliffs, wave-cut platforms, marine terrace, sea arches, and sea stacks

Front 40

name 3 depositional features

Back 40

spits, bars, and tobolos

Front 41

wave-cut cliffs

Back 41

A seaward-facing cliff along a steep shoreline formed by wave erosion at its base and mass wasting.

Front 42

wave-cut platform

Back 42

A bench or shelf along a shore at sea level, cut by wave erosion.

Front 43

if a wave-cut platform is raised above sea level it becomes a _________

Back 43

marine terrace

Front 44

Sea Arches

Back 44

An arch formed by wave erosion when caves on opposite sides of a headland unite.

Front 45

Sea Stack

Back 45

An isolated mass of rock standing just offshore, produced by wave erosion of a headland.

Front 46

baymouth bar

Back 46

a sandbar that cuts completely cross a bay sealing it off from the open ocean

Front 47

tombolo

Back 47

a ridge of sand that connects an island to the mainland or to another island

Front 48

barrier island

Back 48

A low, elongate ridge of sand that parallels the coast. (3 to 30 kilometers offshore)

Front 49

hard stabilization

Back 49

structures built to protect a coast from erosion or to prevent movement of sand along a beach

Front 50

jetties

Back 50

A pair of structures extending into the ocean at the entrance to a harbor or river that are built for the purpose of protecting against storm waves and sediment deposition.

Front 51

groin

Back 51

A short wall built at a right angle to the seashore to trap moving sand.

Front 52

breakwater

Back 52

A structure that protects a near-shore area from breaking waves. (parallel to the coast)

Front 53

seawall

Back 53

A barrier constructed to prevent waves from reaching the area behind the wall. Its purpose is to defend property from the force of breaking waves.

Front 54

beach nourishment

Back 54

A process in which large quantities of sand are added to the beach system to offset losses caused by wave erosion. Building beaches seaward improves beach quality and storm protection.

Front 55

what are the two alternatives to hard stabilization

Back 55

beach nourishment and relocation

Front 56

How might building a dam on a river that flows to the sea affect a coastal beach

Back 56

a lot of the sediment from nearby river supply the sand for beaches. So, the beach would slowly erode away because less sediment is being supplied to the beach

Front 57

pressure gradient

Back 57

refers to how rapidly the pressure changes

Front 58

eye wall

Back 58

doughnut-shaped wall of intense convective activity surrounding the center of the storm

Front 59

eye

Back 59

the very center of a storm

Front 60

storm surge

Back 60

The abnormal rise of the sea along a shore as a result of strong winds.

Front 61

What term is used by geologists to identify the time interval between the passage of successive wave crests or troughs?

Back 61

period

Front 62

What term is used to define the distance between successive wave crests or troughs?

Back 62

wavelength

Front 63

What pattern best describes the motion of water particles in a wave in the open ocean?

Back 63

circular orbit

Front 64

When waves approach shore and touch bottom, what happens to the wave form?

Back 64

wavelength decreases and height increases

Front 65

What pattern of particle movement occurs when wave movement is oblique to the beach?

Back 65

Particals move in a zigzag pattern

Front 66

What situation occurs in the downcurrent direction when a groin is constructed on a beach to prevent erosion of a beach by longshore currents?

Back 66

sand is removed on the downstream side and sand accumulates on the other

Front 67

If the wave period changes so that it is half its original value, how does this change the wavelength?

Back 67

The wavelength will also be half as long. wavelength is proportional to wave period

Front 68

An open water wave with a wavelength of 4 meters moves onshore into shallow water. At what depth does the wave begin to touch bottom?

Back 68

2 meters ( the depth of water affected by the wave as it comes onshore is one-half the wavelength. With a wavelength of 4 meters, the wave would touch bottom at 2 meters.)

Front 69

During which month are hurricanes most likely to occur on the east coast of the United States?

Back 69

Ocean waters are the warmest during August to October, thus producing hurricanes

Front 70

describes the movement of air in a hurricane in the Northern Hemisphere?

Back 70

Air moves up from the surface in a counterclockwise direction.

Front 71

Where do hurricanes that hit the East Coast of the United States form? In which direction do they travel?

Back 71

Hurricanes form in the Atlantic Ocean north of the equator and move in a northwest direction.

Front 72

Hurricanes lose energy when moving over _____

Back 72

land

Front 73

What factors influence where and when hurricane formation takes place?

Back 73

Large amounts of warm moist air is required and a continuous supply is needed to keep it going.

So therefore hurricanes develop near the equator but not within 5 degres of the ewuator because of the Coriolis effect

Front 74

Coriolis Effect

Back 74

A force related to Earth's rotation that gives storms their spin

Front 75

What are the three broad categories of hurricane damage? Which one is responsible for the greatest number of deaths?

Back 75

Storm surge, wind damage, and heavy rains and inland flooding

Storm surge causes the most deaths and damage to structures

Front 76

list 3 tools used to provide data used to track and analyze hurricanes

Back 76

radar, aircraft reconnaissance, and satellites

Front 77

emergent coasts

Back 77

A coast where land formerly below sea level has been exposed by crustal uplift or a drop in sea level or both.

Front 78

submergent coast

Back 78

A coast whose form is largely a result of the partial drowning of a former land surface due to a rise of sea level or subsidence of the crust, or both.

Front 79

estuaries

Back 79

A funnel-shaped inlet of the sea that formed when a rise in sea level or subsidence of land caused the mouth of a river to be flooded. (drowned river mouths)

Front 80

tides

Back 80

The periodic change in the elevation of the ocean surface.

Front 81

spring tides

Back 81

The highest tidal range. Occurs near the times of the new and full moons.

Front 82

neap tides

Back 82

The lowest tidal range. occurring near the times of the first and third quarters of the Moon.

Front 83

name the 3 tidal patterns

Back 83

diurnal, semidiurnal, and mixed tidal patterns

Front 84

diurnal tidal pattern

Back 84

characterized by a single high tide and a single low tide each tidal day

Front 85

semidiurnal tidal pattern

Back 85

exhibits two high tides and two low tides each tidal day. With the two highs about the same height and the two lows about the same height

Front 86

mixed tidal pattern

Back 86

characterized by a large inequality in high water heights low water heights or both. In this case there are usually two high and two low tides each day with high tides of different heights and low tides of different heights

Front 87

tidal current

Back 87

The alternating horizontal movement of water associated with the rise and fall of the tide.

Front 88

flood currents

Back 88

The tidal current associated with the increase in the height of the tide.

Front 89

ebb currents

Back 89

The movement of tidal current away from the shore.

Front 90

periods of little or no current

Back 90

slack water

Front 91

tidal flats

Back 91

A marshy or muddy area that is alternately covered and uncovered by the rise and fall of the tide.

Front 92

tidal deltas

Back 92

A deltalike feature created when a rapidly moving tidal current emerges from a narrow inlet and slows, depositing its load of sediment.

Front 93

how have tides affected Earth's rotation?

Back 93

Tide have been slowing down the rotation of the Earth very slowly