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54 Cards in this Set
- Front
- Back
- 3rd side (hint)
What is a disturbing force?
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The energy that causes ocean waves to form
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Example: A rock thrown into a still pond
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What are the 3 most common types of wave interfaces?
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1) Air-Water (Ocean Waves)
2) Air-Air (Atmospheric Waves) 3) Water-Water (Internal Waves) |
Similar type-system to convergent plate boundaries
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Seismic Sea Waves caused by sea floor movement are also known as:
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Tsunami
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Island Disaster 2004
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What are the 3 known progressive wave types?
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1 - Longitudinal (Particles "push and pull" in same direction as traveling energy)
2 - Transverse (Side-to-side; energy travels perpendicular to direction of vibration) 3 - Orbital (combination of transverse & longitudinal; aka circular waves; also interface waves) |
- Left to Right (Long)
- Up and Down (Trans) - Both together (Orb) |
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Can this energy pass through gaseous matter, liquid matter, and/or solid matter:
- Longitudinal |
All of the above
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Example: Sound
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Can this energy pass through gaseous matter, liquid matter, and/or solid matter:
- Transverse |
Only solids b/c their particles are bound strongly enough to transmit the motion
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What are body waves?
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They transfer energy through a body of matter.
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Examples: Longitudinal & Transverse waves
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The high part of a wave:
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Crests
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The low part of a wave:
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Trough
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Halfway between the crests and the troughs:
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Still water level
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What does 'still water level' imply?
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Zero energy level; No waves
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What is the wave height?
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The vertical distance between the crest and the trough
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What is the wavelength of a wave defined as?
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The horizontal distance between any 2 corresponding points on the wave
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EX: Crest-Crest, Trough-Trough
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What is the formula for wave steepness?
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Wave Height
-------------------- Wavelength |
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If wave steepness exceeds 1/7...
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Then the wave breaks (spills forward) anywhere
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What is the formula for the frequency of a wave?
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1
------------- period |
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What is the basic movement of circular orbital motion as a wave travels?
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The water passes the energy along by moving in a circle
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Aka how does the energy in the wave move
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What is the depth at which circular orbits become so small that movement is negligible?
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The Wave Base
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What is the wave base's depth?
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Wavelength
---------------- 2 |
Measured from still water level
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If water depth is greater than wave base...
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then the wave is a deep-water wave
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The ocean bottom cannot interfere with this kind of wave's wavelength.
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Formula for wave speed:
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Wavelength
------------------- Period |
Length
---------- Time |
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Celerity is also known as...
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Wave speed
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If water depth is less than (L/20)...
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then the wave is a shallow-water wave
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These waves touch the ocean bottom and thus, it's orbital motion is affected by it.
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Formula for the wave speed of deep-water waves:
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1.25*(L)^(.5)
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It's in meters
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For deep-water waves, the longer the wavelength...
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the faster the wave travels
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Has to do with wave speed
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Formula for wave speed of shallow-water waves:
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3.1*(water-depth)^(.5)
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It's in meters
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For shallow-water waves, the deeper the water...
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the faster the wave travels
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Has to do with wave speed
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What is a standing wave enclosed at least partially in a body of water?
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Seiches (Standing wave is produced by sum of other trapped waves' wavelengths)
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Why sloshing back & forth in a bath tub can cause water to eventually spill out
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Of the four types of ocean waves, which are shallow-water and which are deep-water?
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DW: Wind Waves
SW: Tsunamis, Tides, Seiches |
FYI, 4 types are tsunamis, tides, seiches, and wind waves.
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Pressure & Stress is caused over the ocean surface by...
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Wind blowing over it
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Ripples that gather enough energy to become ____ waves are known as...
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___ = gravity
Answer = capillary |
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Surface tension of water causes...
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capillarity
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Area where wind-driven waves are generated is the...
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sea
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Energy imparted by wind increases what 3 parts of a wave?
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The height, speed, and length
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A wave reaches its maximum size when...
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its wave speed is equal to the wind speed
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What is the fetch of a wave?
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Distance over which wind blows to generate waves
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Maximum wave size/speed is dependent on what 3 factors?
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1 - Fetch
2 - Duration (Length of time that wind blows across fetch) 3 - Wind speed (DIfference btwn wave speed & wind speed) |
All factors have to do with the wind blowing on the wave
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How does a 'Wind Sea' create new waves?
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Through a combination of wind forces caused by storms
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What is wave dispersion?
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The sorting of waves by their wavelength
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What are swells?
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Uniform, Symmetrical, long-crested waves with a wave speed faster than wind speed. They move independent of wind with little loss of energy as a result.
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Wind is no longer a factor of control...
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Explains why waves break at the shore.
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Waves have constant wavelengths (as deep-water waves) until they reach the wave base (with respect to the shore). There, their wavelengths begin to decrease (as interact with ocean bottom) and their velocity decreases, thus increasing the wave height as the wave is now a shallow-water one. Once the height > 1/7, the wave breaks.
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Has to do with big difference btwn deep-water waves & shallow-water waves
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What is wave shoaling?
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The transition from deep-water wave to shallow-water wave
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A wave does it when it approaches a shore
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What are the 3 types of breakers & how are they caused?
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1 - Spilling (Waves break on a relatively flat surface)
2 - Plunging (Curling crests form on steep slopes) 3 - Surging (Abrupt beach slopes cause really quick wave energy compression) |
- Flat surface
- Steep slope - Abrupt Slope |
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What is the angle between the front & backside of a wave?
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< 120 degrees
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When is the most dangerous part of a tsunami?
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When it runs up & breaks at the shore
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Difference in periods, wavelengths, depths between tsunamis & wind waves?
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Wind waves period - in seconds
Wind waves wavelength - around 100m Wind waves depth - around 50m Tsunami period - in minutes Tsunami wavelength - > 100km Tsunami depth - TO THE SEA FLOOR |
Tsunami OWNS Wind Waves
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What does the long period of a tsunami imply once it hit the shore?
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Long period means the crest of the wave stretches along the shore (& maybe passed it...) for a long time before receding
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2 signs of possible tsunami activity?
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1 - Nearby Seismic Activity
2 - Highly receding water at the shoreline |
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Is CA at risk from tsunamis?
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Yes
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We live on the Ring of Fire
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What travels faster, seismic waves or tsunami waves?
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Seismic waves
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What can detect tsunamis?
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Buoys & sea floor pressure sensors
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Explain the refraction of a wave as the wave gets close to the shore.
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Waves seldom approach the shore at 90 degrees and thus as they "feel the bottom", they bend (at the base of the wave) such that they arrive nearly parallel to the shoreline though the crest of the wave is then bent.
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Critical point when wave base hits land
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Explain the reflection of a wave as the wave nears the shore.
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Reversal in direction due to bouncing off a boundary (seawall, rock ledge, etc.)
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If a wave approaches the shore at an angle...
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Wave energy will be reflected at an angle equal to the angle the wave came at the barrier.
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