1. Lecture 6: Transforms faults and Convergent margins

6. Kane FZ

11. South Atlantic Spreading Rate

13. Compression Extension Pacific plate Cocos plate EPR 9° North

14. Gravity

17. Bain FZ: Multiple new FZs under extension FZs re-combine under compression 34 21

19. Udintsev FZ, Pac-Ant Ridge Note: Transverse ridges

20. Also know as “J structures”

21. Pitman FZ, Pac-Ant Ridge Note: J structures and Transverse ridges

23. Hawaii: classic flexural bulge due to load of seamounts

24. Satellite gravity

25. Kuril Trench: classic example of flexure at a trench

26. Flexure cause by differential subsidence

27. Gravity anomalies due to flexure across fracture zones Udintsev FZ Eltanin FZ Menard FZ

28. Focal Depths: green 250 km Convergent Margins

29. KK&V Fig 9.1

30. ocean - ocean ocean - continent KK&V Fig 9.18 M&T

31. Focal Depths: green 250 km

32. Focal Depths: Green = 0 – 50 km Yellow = 50 – 250 km Red = > 250 km

33. Note: Collision of Ontong Java Plateau with trench around 15 Ma led to reversal of subduction “polarity” in SW Pacific Ontong Java Plateau

37. For EQ of size small w.r.t wavelength

38. For earthquakes at plate boundaries

41. Note: these are cross sections of beach balls

44. Double Benioff Zone KK&V Fig 9.12 Upper plane: metamorphic reactions in subducted crust Lower plane: metamorphic reactions in subducted mantle

47. Ontong Java Plateau Tonga Trench