1. Incision dynamics and shear stress measurements in submarine channels experiments Pierre Lancien François Métivier Eric Lajeunesse Institut de Physique du Globe de Paris, Laboratoire de Géomorphologie

2. Oct. 2005Pierre Lancien – RCEM 2005 Scientific Questions Physical conditions and dynamics of submarine erosional channel inception Type of current Continuous or sporadic? Density, Velocity Necessary shear stress distribution Morphology S election of width, depth

3. Oct. 2005Pierre Lancien – RCEM 2005 Channel inception and evolution never observed Very few measurements on the stream and the sediment transport Ambiguity of the measured topography and seismic signal Lack of answers

4. Oct. 2005Pierre Lancien – RCEM 2005 Experimental setup Morphology Shields stress measurements Foresights

5. Oct. 2005Pierre Lancien – RCEM 2005 First Ideas Water Water + Sédiments  Slope + sediment layer

6. Oct. 2005Pierre Lancien – RCEM 2005 What do we need ? Easily erodible material Long characteristic settling length Density current (salt water)

7. Oct. 2005Pierre Lancien – RCEM 2005 Experimental Setup Sediment Layer: Plastic Powder Size : 25 microns Density: 1.08 Brine (at the input) Density: 1.03 Flow rate : 1mL/s Q

8. Oct. 2005Pierre Lancien – RCEM 2005 Sample run: Speed : x150 input

9. Oct. 2005Pierre Lancien – RCEM 2005 A continuous flow is sufficient to produce self-channelization

11. Oct. 2005Pierre Lancien – RCEM 2005 Closer view: sediment transport Speed : x 1 Sheet-flow

12. Oct. 2005Pierre Lancien – RCEM 2005 Experimental setup Morphology Shields stress measurements Foresights

13. Oct. 2005Pierre Lancien – RCEM 2005 Time Evolution

14. Oct. 2005Pierre Lancien – RCEM 2005 Time Evolution

16. Oct. 2005Pierre Lancien – RCEM 2005 Frontal lobe Incision

18. Oct. 2005Pierre Lancien – RCEM 2005 Aspect ratios in Nature Width/Depth = 10 Experiments

19. Oct. 2005Pierre Lancien – RCEM 2005 Phase Diagram

20. Oct. 2005Pierre Lancien – RCEM 2005 Experimental setup Morphology Shields stress measurements Foresights

21. Oct. 2005Pierre Lancien – RCEM 2005 Experimental Setup

22. Oct. 2005Pierre Lancien – RCEM 2005 We measure: Position (3D) Velocity Time We deduce: Particle size Velocity profile Particle-with-shadow Tracking Technique

23. Oct. 2005Pierre Lancien – RCEM 2005 Velocity Profile Kneller & Buckee

24. Oct. 2005Pierre Lancien – RCEM 2005 Shear stress Measurement Kneller & Buckee

25. Oct. 2005Pierre Lancien – RCEM 2005 Velocity Profile Classical particle tracking technique Particle-with-shadow tracking technique

27. Oct. 2005Pierre Lancien – RCEM 2005 D

28. Oct. 2005Pierre Lancien – RCEM 2005 Conclusions and foresights It is possible to reproduce micro-scale submarine channels using a continuous density current. Density current and erosion characterization Experimental channels characterization Scaling laws, extend to natural submarine channels

29. Oct. 2005Pierre Lancien – RCEM 2005

30. Pierre Lancien François Métivier Eric Lajeunesse

32. Questions ?

33. Oct. 2005Pierre Lancien – RCEM 2005 Injection effects  x 10 Caldera (jet zone) Channel

34. Oct. 2005Pierre Lancien – RCEM 2005 Experimental Setup Sediment Layer: Plastic Powder Size : 25 microns Density: 1.08 Brine (at the input) Density: 1.03 Flow rate : 1g/s

35. Oct. 2005Pierre Lancien – RCEM 2005 Principle

36. Oct. 2005Pierre Lancien – RCEM 2005 Channel morphology Width vs Flow rateAspect ratio : 5 -10

37. Oct. 2005Pierre Lancien – RCEM 2005

38. Oct. 2005Pierre Lancien – RCEM 2005 Flow RateSlope Umax Ubed

39. Oct. 2005Pierre Lancien – RCEM 2005

40. Oct. 2005Pierre Lancien – RCEM 2005

41. Oct. 2005Pierre Lancien – RCEM 2005

42. Oct. 2005Pierre Lancien – RCEM 2005 Continuous works Velocity profile Aspect ratio  /  c about 10 Conclusions & Foresights Type of current Continuous or sporadic? Density, Velocity Morphology Selection of width, depth Necessary shear stress distribution Questions Answers Future Extend on the sides Scaling Laws