1. Wave Erosion and Marine Geology

2. Wave Motions Particles in a wave travel circular paths The water in a deep-water wave does not move forward Below wave base, wave effects are negligible

3. The Highest Recorded Ocean Wave

4. When Waves Meet the Shore When the bottom interferes with wave motion, the wave steepens and the top overtakes the bottom.

5. Wave Refraction Waves change path when they reach shallow water Wave energy is concentrated on headlands and spread out in bays

6. Rips When waves break parallel to a beach, rips occur

7. Storm Waves: Galveston, Texas, September 8, 1900: 6000-8000 dead 3600 houses destroyed

8. Raising Galveston – 6 in. to 17 ft.

9. “ A rickety maze such as Dr. Seuss might have drawn ”

10. The Lift in Progress

11. Pumping in the Sand

12. The Galveston Seawall

13. In the long run, nothing is as futile as trying to resist shoreline change. Change can be resisted for a while, but when the water wants something badly enough, it will come in and take it.

14. Property Values and Shoreline Erosion If more than half the original lot is left, it’s Location, Location, Location After that, it becomes obvious there soon won’t be any location left

15. Freak Waves Addition of waves of different frequencies Theoretically could reach 200 feet in Gulf of Alaska One nearly sank the Queen Mary in WWII, with 15,000 troops aboard.

16. Marine Erosion Chemical Attack Abrasion Wave Impact Compressed Air Backwash

17. Longshore and Beach Drift Most Beach Sand Is Created by Weathering and Carried to Coasts by Rivers Beach Sand Moves along the Coast by Longshore and Beach Drift

18. Types of Coast Degree of Modification Primary - Not Modified Much by Wave Action Secondary - Highly Modified by Wave Action History Emergent - Land Rises or Water Level Falls Submergent - Land Sinks or Water Level Rises Dominant Process Erosional Depositional

19. Effects of the Pleistocene Sea level has risen at least 100 meters in the last 18,000 years Most coastlines globally are submergent Primary coastlines are very common

20. Secondary Coasts Are Modified by Marine Erosion or Deposition

21. Secondary Coasts Erosion Stack Terraces Tombolo Erosion rate becomes very slow – wave energy dissipated crossing the wave-cut terrace. –Cliffs become higher, meaning more material to move. Deposition Spit Lagoon Baymouth Bar Barrier Bar

22. Primary Coastlines Are Very Common Drowned River Valleys (Estuaries) Drowned Glacial Valleys (Fiords)

23. Other Ways Primary Coasts Can Form Deltas Volcanic Activity Uplift

24. Primary and Secondary Coastlines

25. Delta Coasts Deposition-Dominated Wave Dominated Tide-Dominated

26. The Mississippi – A Deposition- Dominated Delta

27. Yukon and Nile Deltas – Balance of Deposition and Wave Action

28. Sao Francisco, Brazil – A Wave- Dominated Delta

29. Ganges, Bangladesh – A Tide- Dominated Delta

30. Reefs Are a Major Type of Coast in Tropical Areas

31. Tarawa – A Typical Atoll

32. Reefs Also Form along the Edges of Large Islands and Continents These Are Barrier Reefs Australia Yucatan Belize West Florida

33. Turbidity Flows – Grand Banks, 1929