Sea and Swell Sea or sea area –  where wind-  driven waves are  generated Swell – uniform,  symmetrical  waves  originat...
Factors Affecting Wave Energy Wind speed Wind duration Fetch – distance over which wind blows                  © 2011 P...
Wave Height Directly related to wave  energy Wave heights usually less  than 2 meters (6.6 feet) Breakers called whitec...
Global Wave Heights         © 2011 Pearson Education, Inc.
Beaufort Wind Scale     © 2011 Pearson Education, Inc.
Maximum Wave Height   USS Ramapo (1933): 152-meters (500 feet) long ship    caught in Pacific typhoon   Waves 34 meters ...
Wave Energy Fully developed sea    Maximum wave height, wavelength for     particular fetch, speed, and duration of     ...
Swells Longer wavelength waves travel faster and outdistance other waves   Wave train – a group of waves with similar   ...
Wave Train Movement        © 2011 Pearson Education, Inc.
Waves in Surf Zone Surf zone – zone of breaking waves near shore Shoaling water – water becoming gradually more  shallow...
Waves Approaching Shore As a deep-water wave becomes a shallow-water wave:    Wave speed decreases    Wavelength decrea...
Waves Approaching Shore         © 2011 Pearson Education, Inc.
Three Types of Breakers Spilling Plunging Surging             © 2011 Pearson Education, Inc.
Spilling Breakers Gently sloping sea  floor Wave energy expended  over longer distance Water slides down  front slope o...
Plunging Breakers Moderately steep sea  floor Wave energy expended  over shorter distance Best for board surfers Curli...
Surging Breakers Steepest sea floor Energy spread over  shortest distance Best for body surfing Waves break on the  sh...
Surfing Like riding a gravity-operated water sled Balance of gravity and buoyancy Skilled surfers position board on wav...
Wave Refraction Waves rarely approach shore at a perfect 90 degree  angle. As waves approach shore, they bend so wave cr...
Wave Refraction         © 2011 Pearson Education, Inc.
Wave Refraction Gradually erodes  headlands Sediment accumulates  in bays                © 2011 Pearson Education, Inc.
Wave Reflection Waves and wave energy  bounced back from  barrier Reflected wave can  interfere with next  incoming wave...
Standing Waves Two waves with same wavelength moving in  opposite directions Water particles move vertically and horizon...
Tsunami Seismic sea waves Originate from sudden sea floor topography changes   Earthquakes – most common      cause   ...
Tsunami Characteristics Long wavelengths (> 200 km or 125 miles) Behaves as a shallow-water wave                 © 2011 ...
Tsunami          © 2011 Pearson Education, Inc.
Tsunami Destruction    Sea level can rise up to 40 meters (131 feet) when a     tsunami reaches shore.               © 20...
Tsunami Most occur in Pacific Ocean   More earthquakes and    volcanic eruptions Damaging to coastal  areas Loss of hu...
Historical Tsunami Krakatau – 1883    Indonesian volcanic eruption Scotch Cap, Alaska/Hilo, Hawaii – 1946    Magnitude...
Historical LargeTsunami          © 2011 Pearson Education, Inc.
Banda Aceh Before FloodingImagery collected June 23, 2004
Banda Aceh FloodingImagery collected December 28, 2004
Tsunami Satellite Picture -Before & After - BandaAceh Shore
Banda Aceh Grand Mosque (Before Tsunami)Imagery collected June 23, 2004
Banda Aceh Grand MosqueImagery collected December 28, 2004
Banda Aceh Detail Before DebrisImagery collected June 23, 2004
Banda Aceh Debris DetailImagery collected December 28, 2004
March 11, 2011
Waves - Swell, Types, Reflection, Refraction, Tsunamis
Waves - Swell, Types, Reflection, Refraction, Tsunamis
Waves - Swell, Types, Reflection, Refraction, Tsunamis
Waves - Swell, Types, Reflection, Refraction, Tsunamis
Waves - Swell, Types, Reflection, Refraction, Tsunamis
Waves - Swell, Types, Reflection, Refraction, Tsunamis
Waves - Swell, Types, Reflection, Refraction, Tsunamis
Waves - Swell, Types, Reflection, Refraction, Tsunamis
Waves - Swell, Types, Reflection, Refraction, Tsunamis
Waves - Swell, Types, Reflection, Refraction, Tsunamis
Waves - Swell, Types, Reflection, Refraction, Tsunamis
Waves - Swell, Types, Reflection, Refraction, Tsunamis
Waves - Swell, Types, Reflection, Refraction, Tsunamis
Waves - Swell, Types, Reflection, Refraction, Tsunamis
Waves - Swell, Types, Reflection, Refraction, Tsunamis
Waves - Swell, Types, Reflection, Refraction, Tsunamis
Waves - Swell, Types, Reflection, Refraction, Tsunamis
Waves - Swell, Types, Reflection, Refraction, Tsunamis
Upcoming SlideShare
Loading in …5
×

Waves - Swell, Types, Reflection, Refraction, Tsunamis

193 views
175 views

Published on

0 Comments
1 Like
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total views
193
On SlideShare
0
From Embeds
0
Number of Embeds
1
Actions
Shares
0
Downloads
16
Comments
0
Likes
1
Embeds 0
No embeds

No notes for slide

Waves - Swell, Types, Reflection, Refraction, Tsunamis

  1. 1. Sea and Swell Sea or sea area – where wind- driven waves are generated Swell – uniform, symmetrical waves originating from sea area © 2011 Pearson Education, Inc.
  2. 2. Factors Affecting Wave Energy Wind speed Wind duration Fetch – distance over which wind blows © 2011 Pearson Education, Inc.
  3. 3. Wave Height Directly related to wave energy Wave heights usually less than 2 meters (6.6 feet) Breakers called whitecaps form when wave reaches critical steepness Beaufort Wind Scale describes appearance of sea surface © 2011 Pearson Education, Inc.
  4. 4. Global Wave Heights © 2011 Pearson Education, Inc.
  5. 5. Beaufort Wind Scale © 2011 Pearson Education, Inc.
  6. 6. Maximum Wave Height  USS Ramapo (1933): 152-meters (500 feet) long ship caught in Pacific typhoon  Waves 34 meters (112 feet) high © 2011 Pearson Education, Inc.
  7. 7. Wave Energy Fully developed sea  Maximum wave height, wavelength for particular fetch, speed, and duration of winds at equilibrium conditions Swell  Uniform, symmetrical waves that travel outward from storm area  Long crests  Transport energy long distances © 2011 Pearson Education, Inc.
  8. 8. Swells Longer wavelength waves travel faster and outdistance other waves  Wave train – a group of waves with similar characteristics  Wave dispersion – sorting of waves by wavelengths Wave train speed is ½ speed of individual wave © 2011 Pearson Education, Inc.
  9. 9. Wave Train Movement © 2011 Pearson Education, Inc.
  10. 10. Waves in Surf Zone Surf zone – zone of breaking waves near shore Shoaling water – water becoming gradually more shallow When deep water waves encounter shoaling water less than ½ their wavelength, they become transitional waves. © 2011 Pearson Education, Inc.
  11. 11. Waves Approaching Shore As a deep-water wave becomes a shallow-water wave:  Wave speed decreases  Wavelength decreases  Wave height increases  Wave steepness (height/wavelength) increases  When steepness > 1/7, wave breaks © 2011 Pearson Education, Inc.
  12. 12. Waves Approaching Shore © 2011 Pearson Education, Inc.
  13. 13. Three Types of Breakers Spilling Plunging Surging © 2011 Pearson Education, Inc.
  14. 14. Spilling Breakers Gently sloping sea floor Wave energy expended over longer distance Water slides down front slope of wave © 2011 Pearson Education, Inc.
  15. 15. Plunging Breakers Moderately steep sea floor Wave energy expended over shorter distance Best for board surfers Curling wave crest © 2011 Pearson Education, Inc.
  16. 16. Surging Breakers Steepest sea floor Energy spread over shortest distance Best for body surfing Waves break on the shore © 2011 Pearson Education, Inc.
  17. 17. Surfing Like riding a gravity-operated water sled Balance of gravity and buoyancy Skilled surfers position board on wave front  Can achieve speeds up to 40 km/hour (25 miles/hour) © 2011 Pearson Education, Inc.
  18. 18. Wave Refraction Waves rarely approach shore at a perfect 90 degree angle. As waves approach shore, they bend so wave crests are nearly parallel to shore. © 2011 Pearson Education, Inc.
  19. 19. Wave Refraction © 2011 Pearson Education, Inc.
  20. 20. Wave Refraction Gradually erodes headlands Sediment accumulates in bays © 2011 Pearson Education, Inc.
  21. 21. Wave Reflection Waves and wave energy bounced back from barrier Reflected wave can interfere with next incoming wave With constructive interference, can create dangerous plunging breakers © 2011 Pearson Education, Inc.
  22. 22. Standing Waves Two waves with same wavelength moving in opposite directions Water particles move vertically and horizontally Water sloshes back and forth © 2011 Pearson Education, Inc.
  23. 23. Tsunami Seismic sea waves Originate from sudden sea floor topography changes  Earthquakes – most common cause  Underwater landslides  Underwater volcano collapse  Underwater volcanic eruption  Meteorite impact – splash waves © 2011 Pearson Education, Inc.
  24. 24. Tsunami Characteristics Long wavelengths (> 200 km or 125 miles) Behaves as a shallow-water wave © 2011 Pearson Education, Inc.
  25. 25. Tsunami © 2011 Pearson Education, Inc.
  26. 26. Tsunami Destruction  Sea level can rise up to 40 meters (131 feet) when a tsunami reaches shore. © 2011 Pearson Education, Inc.
  27. 27. Tsunami Most occur in Pacific Ocean  More earthquakes and volcanic eruptions Damaging to coastal areas Loss of human lives © 2011 Pearson Education, Inc.
  28. 28. Historical Tsunami Krakatau – 1883  Indonesian volcanic eruption Scotch Cap, Alaska/Hilo, Hawaii – 1946  Magnitude 7.3 earthquake in Aleutian Trench Papua New Guinea – 1998  Pacific Ring of Fire magnitude 7.1 earthquake Indian Ocean – 2004  Magnitude 9.3 earthquake off coast of Sumatra Japan – 2011  Magnitude 9.0 earthquake off coast of Japan © 2011 Pearson Education, Inc.
  29. 29. Historical LargeTsunami © 2011 Pearson Education, Inc.
  30. 30. Banda Aceh Before FloodingImagery collected June 23, 2004
  31. 31. Banda Aceh FloodingImagery collected December 28, 2004
  32. 32. Tsunami Satellite Picture -Before & After - BandaAceh Shore
  33. 33. Banda Aceh Grand Mosque (Before Tsunami)Imagery collected June 23, 2004
  34. 34. Banda Aceh Grand MosqueImagery collected December 28, 2004
  35. 35. Banda Aceh Detail Before DebrisImagery collected June 23, 2004
  36. 36. Banda Aceh Debris DetailImagery collected December 28, 2004
  37. 37. March 11, 2011

×