Chapter 8 Oceanography HW

What is the speed in meters per second of a deep water wave with a wavelength of 1.5 meters?

1.53 meters per second

A deep-water wave occurs when the water depth is equal to at least:

1/2 of the wavelength.

On average how many supertankers or containerships are reported missing each year without a trace?

10

Based on the graph, what is the approximate period of a deep-water wave with a speed of 15 meters per second?

10 seconds

You live on an island in the Pacific. An earthquake of magnitude 8.5 off the coast of Japan, 8000 km away, generates a tsunami with a wavelength of 200 km. The average water depth between your island and Japan is 4900 m. If a tsunami warning is issued for your island, how many hours will you have before the waves arrive?

10.14 hours

What is the speed in meters per second of a deep water wave with a wavelength of 3.5 meters?

2.34 meters per second

What is the speed in meters per second of a deep water wave with a wavelength of 5 meters?

2.8 meters per second

In the open ocean, 1 wave in ________ will be over twice the height of the wave average.

23

Based on the graph, what is the approximate speed, in meters per second, of a deep-water wave with a wavelength of 400 meters?

25 meters per second

In the open ocean, 1 wave in ________ will be four times as high as the height of the wave average.

300,000

Waves from separate sea areas move away as swell and produce an interference pattern when they come together. If Sea A has wave heights of 1.5 meters and Sea B has wave heights of 3.5 meters, what would be the height of waves resulting from constructive interference?

5 meters

What results when two waves, in phase and with the same wavelength, interact?

A wave with an amplitude that is the sum of the amplitudes of the initial two waves.

Rogue waves are created along the "Wild Coast" off the southeast coast of ________, where the Agulhas Current flows directly against large Antarctic storm waves.

Africa

Why does the wave height of a tsunami increase as the tsunami enters shallow water?

In shallow water, the energy of the tsunami must be contained within a smaller water column.

What occurs more often, pure destructive, pure constructive, or mixed interference?

Mixed interference

Which ocean is associated with most tsunamis?

Pacific Ocean

Which of the following are names for large ocean waves that can be created by constructive interference?

Superwaves Rogue waves Freak waves

Judge the following sentence according to the criteria given below: Transform faults do not generally generate tsunami BECAUSE the side-to-side movement of these faults does not change the volume of the ocean basin.

The assertion and the reason are both correct, and the reason is valid.

Judge the following sentence according to the criteria given below: Many people call tsunami "tidal waves" BECAUSE they are related to the tides.

The assertion is correct, but the reason is incorrect.

What is the relationship between wave base and wavelength?

The depth of the wave base is one-half the wavelength of the waves.

Why does wave height increase as waves enter shallow water?

The energy of the wave must be contained within a smaller water column in shallow water.

What causes wave refraction?

The part of a wave in shallow water slows down, causing the wave to bend and line up nearly parallel to the shore.

What triggers a wave traveling across the ocean to finally release its energy?

The wave begins to interact with the sea floor as it moves into shallower water.

What is an interference pattern?

The wave pattern produced when two or more waves interact.

Why do ocean waves bend around headlands?

The waves are moving more slowly just in front of the headland, causing the waves to bend.

Will Sumatra experience another tsunami like the destructive one of December 2004?

This is likely, because Sumatra is near many ocean trenches.

Why do ships at sea tend not to notice tsunamis?

Tsunamis in deep water have small wave height and long wavelength.

How does water move as waves pass?

Water moves in a circle in the same direction as wave movement.

How does wave amplitude change with depth in water?

Wave amplitude decreases as depth increases.

Which of the following statements about wave period is most accurate?

Wave period is the inverse of wave frequency.

How does wave refraction at headlands affect deposition and erosion?

Wave refraction at the headland increases erosion at the headland and causes deposition in adjacent bays.

What does the term "in phase" refer to?

Waves in phase have identical wavelengths and are aligned peak-to-peak and trough-to-trough

How are wave period and wavelength related?

Waves with shorter periods have shorter wavelengths.

When will perfect destructive interference occur?

When two waves that are 180 degrees out-of-phase interfere.

When will perfect constructive interference occur for waves that are in phase and moving at the same velocity?

When waves with identical wavelengths interfere.

Of the following bathymetric conditions, which one(s) would likely produce spilling breakers? Choose all that apply.

a gently sloping, rocky bottom a gently sloping, sandy bottom

What is a tsunami?

a series of water waves that travel away from a fault in all directions at high speed

Ripple like clouds in the sky are an example of ________ waves.

atmospheric

Wave refraction is __________.

bounding of waves

What type of plate boundary are most tsunamis associated with?

convergent plate boundaries

As a wave approaches shore, its characteristics change by _____________________.

decreasing speed, increasing steepness

The majority of tsunami are caused by underwater ________.

fault movement

Which of the following caused the Indian Ocean tsunami of 2004?

fault movement

The height of a wave depends upon:

fetch, wind duration, and wind speed.

Which of the following best describes a plunging breaker?

forms on moderately sloped shorelines to create curling crests

Refraction causes headlands to be areas of ________ surfing and sites of ________.

good; erosion

In general the restoring force for wind-generated waves is:

gravity

As a wave begins to feel bottom near a shoreline, its wave height:

increases and its wavelength decreases

Tidal movement, turbidity currents, wind stress, and even passing ships at the surface create ________ waves.

internal

A disadvantage shared by wave, solar and wind energy is that ___________________________.

it is not available on demand, and there currently is no viable way to store the energy

Sound travels as ________ waves.

longitudinal

Which of the following is the least frequent cause of a tsunami in recent centuries?

meteorite impacts

Most of the year, and most of the time, the movement of sediment and water (longshore current) along the California coast is from __________.

north to south

Ocean waves in motion are classified as ______waves.

orbital

Waves at the ocean surface are ________ waves.

orbital

Ocean surface waves are:

orbital waves

A vast majority of all large tsunami are generated in the ________ Ocean.

pacific

The time between two successive waves is called the:

period

Which type of breaker has a curling crest that moves over an air pocket?

plunging breaker

Waves that are breaking along the shore and are forming curling crests over air pockets are called:

plunging breakers.

Submarines sometimes ride out heavy storms in deep water by submerging. That is a practical application of utilizing the ____________________.

principle of decreasing orbital motion with depth

A tsunami is considered to be a:

shallow water wave

Constructive interference results in larger waves whereas destructive interference produces:

smaller waves

Which type of breaker is a turbulent mass of air and water that runs down the front slope of the wave as it breaks?

spilling breaker

If a surfer wishes to have a really long ride, what type of wave should he or she look for?

spilling breakers

A wave will begin to break when:

steepness = 1:7.

What disturbing force is responsible for most ocean waves that eventually break on shore?

storm-generated winds that blow across the surface

Which type of breaker forms waves the present the greatest challenge to body surfers?

surging breaker

Which type of breaker forms when the waves build up and break right at the shoreline?

surging breaker

What type of breaker would pose the most danger to people playing or swimming in the surf zone?

surging breakers

Examine the five words and/or phrases and determine the relationship among the majority of words/phrases. Choose the one option that does not fit the pattern.

swell

What is refraction?

the bending of waves due to a change in wave velocity

What is the wavelength?

the distance between consecutive wave crests or troughs

What is the wave height?

the distance between the highest and lowest part of the wave

What is the crest of a wave?

the highest part of the wave

Of the following statements about ocean waves, which one(s) describe wave period? Choose all that apply.

the inverse of wave frequency the time it takes for one full wavelength to pass a given point

What is the wave base?

the lower limit of wave-induced motion in the water

What is the trough of a wave?

the lowest part of the wave

What causes the three different types of breakers?

the steepness of the beach slope

What is the wave period?

the time it takes for one wavelength of a wave to pass a particular point

How are tsunamis generated?

through displacement of the seafloor under water

________ waves also known as side-to-side waves

transverse

The speed of a shallow-water wave is proportional to:

water depth

Which one of the following variables is necessary to determine the speed of shallow-water waves? Select only one answer.

water depth

The depth below the surface where the circular orbits become so small that movement is negligible is called the ________.

wave base

The number of wave crests passing a fixed location per unit of time is called the ________.

wave frequency

The time it takes one full wave to pass a fixed position is called the ________.

wave period

An unintended consequence of the jetty that protects the harbor entrance at Newport Harbor, California is a wave pattern that has crippled and killed many body surfers due to ________.

wave reflection

Waves converge on headlands due to:

wave refraction

"Whitecaps" form when _____________________.

wave steepness reaches a ratio of 1:7

The horizontal distance between wave crest to crest is called the ________.

wavelength

The speed of a deep-water wave is proportional to:

wavelength

Wave speed is equal to:

wavelength divided by period.

The circular motion of water molecules extends to a depth that is equal to:

wavelength/2.

The largest wind-generated waves tend to be associated with the:

westerlies.

Conditions for the development of wave energy are most optimal along ________ shores in the ________ Hemisphere.

western; Southern

Most ocean waves form as a result of:

winds blowing across the ocean surface.