Waves and Tsunamis EOSC 114 Review Questions with Complete Solutions Graded A+
What is the shape of the coast line dependent on? - Answers -many processes of varying time scales
Sediment transport and deposition
Erosion
Uplift and subsidence
how is the ocean linked with the atmosphere, and what is the difference between waves and surface
currents? - Answers When wind blows over the ocean, it drags on the surface and transfers energy from
the atmosphere to the water, thus creating waves and currents. Very large scale, permanent winds that
blow over the ocean produce surface currents, which transport both matter (water) and energy. Winds
that blow occasionally or over smaller areas produce waves, which transport energy in the direction of
the wind
how do we define waves? - Answers The mechanical expression of energy
describe the anatomy of a wave (crest, trough,wavelength, amplitude, period, frequency, speed) -
Answers -Crest and trough are the highest and lowest point respectively
-Wavelength is the distance between two successive crests or troughs
-Amplitude is the vertical distance between trough and calm sea level
-Period is the time for one wavelength to pass a point
-Frequency is the number of waves which pass a point in a unit of time
-speed or celerity is the distance traveled for a unit of time
What is steepness and how is it measured? - Answers a measure of the "peakedness" of a wave; the
ratio of Height to Wavelength, H / L; (no units)
,What is wave energy related to and what is the constriction in this relationship? - Answers The energy
transported by waves is related to the wave height, H, waves with great heights transport more energy.
This simple correlation applies only to deep-water waves
Usually, though not all the time, waves with great heights also have long wavelengths.
How is wave period related to other wave characteristics?
A) Period = Frequency
B) Period = Frequency ÷ Wavelength
C) Period = 1 / Frequency
D) Period = 1 / Wavelength
E) Period = 1 / Celerity - Answers C) Period = 1 / Frequency
what is Generating/Disturbing Force and what do we use it for? - Answers Generating force is the force
that causes a wave to form and we use it to classify different types of waves.
what are the four different waves based on generating force? - Answers Wind wave-wind over water
Seiche-changes in atmospheric pressure
Tsunami- Faulting of sea floor, undersea volcanic eruption, landslide into ocean
Tide-Gravitational attraction between earth-sun and earth-moon; rotation of earth
what is restoring force and how do we use it? - Answers Restoring force is the force that returns a wave
to its resting state and we use it to classify different waves
what are the two waves classified by restoring force? - Answers Capillary wave-surface tension
Gravity-surface gravity waves (Wind wave, seiche, tsunami, tide)
, What are capillary waves and how do they aid in the generation of wind driven waves? - Answers
Capillary waves are tiny waves with wavelengths about the size of your fingernail and are restored by
surface tension.
The wind pushes the surface "skin" of the ocean and a series of small wrinkles, the capillary waves,
develops. As the wind speed increases, or as wind blows over longer periods of time and over the same
area, more energy is transferred to the surface ocean and the waves grow larger.
What is sea state? - Answers An assessment of the ocean's conditions or the roughness of the ocean
surface
The amount of energy transferred to the ocean can be estimated by the height of the waves produced.
what three factors does sea state depend on? - Answers -Wind strength/speed
-Fetch
-Wind duration, the length of time that the wind has been blowing over the fetch
As wind energy transfers to the ocean, what are the wave stages or development? - Answers Capillary
waves to ripples to chop to fully developed
What is a fully developed fetch? - Answers A specific fetch in the ocean is said to be fully developed once
it has absorbed the maximum amount of energy it can contain
The waves of a fully developed sea can achieve the maximum height possible for a given wind speed,
fetch and duration of wind.
What happens if additional energy is added to a fully developed fetch? - Answers any additional energy
input by the wind is balanced by energy dissipated by breaking waves. Waves in this condition are
chaotic, where there are waves of varying heights, lengths, speed, and direction.
How are waves sorted as they move away from a fetch? - Answers They are sorted by speed and
wavelength (longer wavelength is related to more speed). Thus the waves with the longest wavelength
and fastest speed leave the fetch first. The last waves to leave are the slowest and shortest waves
What are swells and wave trains? - Answers When waves leave a fetch in an organized manner they are
called swells. Swells propagate away from the fetch in groups called wave trains
What is the shape of the coast line dependent on? - Answers -many processes of varying time scales
Sediment transport and deposition
Erosion
Uplift and subsidence
how is the ocean linked with the atmosphere, and what is the difference between waves and surface
currents? - Answers When wind blows over the ocean, it drags on the surface and transfers energy from
the atmosphere to the water, thus creating waves and currents. Very large scale, permanent winds that
blow over the ocean produce surface currents, which transport both matter (water) and energy. Winds
that blow occasionally or over smaller areas produce waves, which transport energy in the direction of
the wind
how do we define waves? - Answers The mechanical expression of energy
describe the anatomy of a wave (crest, trough,wavelength, amplitude, period, frequency, speed) -
Answers -Crest and trough are the highest and lowest point respectively
-Wavelength is the distance between two successive crests or troughs
-Amplitude is the vertical distance between trough and calm sea level
-Period is the time for one wavelength to pass a point
-Frequency is the number of waves which pass a point in a unit of time
-speed or celerity is the distance traveled for a unit of time
What is steepness and how is it measured? - Answers a measure of the "peakedness" of a wave; the
ratio of Height to Wavelength, H / L; (no units)
,What is wave energy related to and what is the constriction in this relationship? - Answers The energy
transported by waves is related to the wave height, H, waves with great heights transport more energy.
This simple correlation applies only to deep-water waves
Usually, though not all the time, waves with great heights also have long wavelengths.
How is wave period related to other wave characteristics?
A) Period = Frequency
B) Period = Frequency ÷ Wavelength
C) Period = 1 / Frequency
D) Period = 1 / Wavelength
E) Period = 1 / Celerity - Answers C) Period = 1 / Frequency
what is Generating/Disturbing Force and what do we use it for? - Answers Generating force is the force
that causes a wave to form and we use it to classify different types of waves.
what are the four different waves based on generating force? - Answers Wind wave-wind over water
Seiche-changes in atmospheric pressure
Tsunami- Faulting of sea floor, undersea volcanic eruption, landslide into ocean
Tide-Gravitational attraction between earth-sun and earth-moon; rotation of earth
what is restoring force and how do we use it? - Answers Restoring force is the force that returns a wave
to its resting state and we use it to classify different waves
what are the two waves classified by restoring force? - Answers Capillary wave-surface tension
Gravity-surface gravity waves (Wind wave, seiche, tsunami, tide)
, What are capillary waves and how do they aid in the generation of wind driven waves? - Answers
Capillary waves are tiny waves with wavelengths about the size of your fingernail and are restored by
surface tension.
The wind pushes the surface "skin" of the ocean and a series of small wrinkles, the capillary waves,
develops. As the wind speed increases, or as wind blows over longer periods of time and over the same
area, more energy is transferred to the surface ocean and the waves grow larger.
What is sea state? - Answers An assessment of the ocean's conditions or the roughness of the ocean
surface
The amount of energy transferred to the ocean can be estimated by the height of the waves produced.
what three factors does sea state depend on? - Answers -Wind strength/speed
-Fetch
-Wind duration, the length of time that the wind has been blowing over the fetch
As wind energy transfers to the ocean, what are the wave stages or development? - Answers Capillary
waves to ripples to chop to fully developed
What is a fully developed fetch? - Answers A specific fetch in the ocean is said to be fully developed once
it has absorbed the maximum amount of energy it can contain
The waves of a fully developed sea can achieve the maximum height possible for a given wind speed,
fetch and duration of wind.
What happens if additional energy is added to a fully developed fetch? - Answers any additional energy
input by the wind is balanced by energy dissipated by breaking waves. Waves in this condition are
chaotic, where there are waves of varying heights, lengths, speed, and direction.
How are waves sorted as they move away from a fetch? - Answers They are sorted by speed and
wavelength (longer wavelength is related to more speed). Thus the waves with the longest wavelength
and fastest speed leave the fetch first. The last waves to leave are the slowest and shortest waves
What are swells and wave trains? - Answers When waves leave a fetch in an organized manner they are
called swells. Swells propagate away from the fetch in groups called wave trains
