1. Geology 3120 - Introduction to Strike-Slip Faults

2. Levant Strike-Slip Faults

5. Outline Stick-Slip and Creep Andersonian Theory Kinematics Strike-Slip Faults on Continental Margins Strike-Slip Faults on Mid-Ocean Ridges

6. Stick-Slip: Elastic Rebound Theory 

7. Elastic Rebound Theory Imagine a fence across an active fault Imagine a fence across an active fault

8. Elastic Rebound Theory Imagine a fence across an active fault Imagine a fence across an active fault Regional deformation occurs but the fault does not break. The fence becomes curved. Regional deformation occurs but the fault does not break. The fence becomes curved.

9. Elastic Rebound Theory Imagine a fence across an active fault Imagine a fence across an active fault Regional deformation occurs but the fault does not break. Regional deformation occurs but the fault does not break. Once the fault breaks, the fence is sheared in half and marks offset Once the fault breaks, the fence is sheared in half and marks offset Note that far-field strain may limit whether the fault accommodates all the plate motion at its trace Note that far-field strain may limit whether the fault accommodates all the plate motion at its trace

10. Elastic Rebound Theory

12. Creep (Aseismic Slip) Imagine a fence across an active fault Imagine a fence across an active fault Slip occurs slowly on the fault continually over time. Slip occurs slowly on the fault continually over time. Creeping faults do not store elastic energy that might be released by a stick-slip event (an earthquake) Creeping faults do not store elastic energy that might be released by a stick-slip event (an earthquake)

13. Andersonian Theory

14. Conjugate Strike-Slip Faults

15. Determining Sense of Slip

16. Right-Lateral (Dextral)

17. Left-Lateral (Sinistral)

18. Arrow Heads ( ) and Tails ( ) Block moving toward you like an arrowhead heading towards you Block moving away from you like seeing the feathers of an arrow

19. Arrow Heads ( ) and Tails ( ) Right-lateral or left-lateral? Right-lateral or left-lateral?

20. Arrow Heads ( ) and Tails ( ) Left-lateral Left-lateral

21. Arrow Heads ( ) and Tails ( ) Sinistral or Dextral? Sinistral or Dextral?

22. Arrow Heads ( ) and Tails ( ) Dextral Dextral

23. Strike-Slip Faulting: Shallow Brittle vs Deep Shear

24. Strike-Slip Faulting: EQ’s = dislocations See http://www.data.scec.org/Module/links/landrupt.htmlhttp://www.data.scec.org/Module/links/landrupt.html Landers rupture propagation movies

25. Strike-Slip Faults on Continental Margins What is the sense of slip? What is the sense of slip? N 50 m

26. Strike-Slip Faults on Continental Margins Right-lateral (dextral) Right-lateral (dextral) N 50 m

27. Transtension

28. Development of a Pull-Apart Basin

29. Pull-Apart Basin

30. Initial Releasing Bend

31. Evolution of a Releasing Bend

32. Normal (-) Flower Structure - Tulip

33. Transpression

34. Development of a Restraining Bend

35. Initial Restraining Bend

36. Evolution of a Restraining Bend

37. Reverse (+) Flower Structure - Palm

38. Summary of Flower Structures - Palms & Tulips

39. Oceanic Strike Slip fault: Transforms

40. Strike-Slip Faults on Mid-Ocean Ridges What is the sense of slip? What is the sense of slip?

41. Strike-Slip Faults on Mid-Ocean Ridges Right-lateral (Dextral) Right-lateral (Dextral)

42. Pacific-Antarctic Ridge Magnetic anomalies from present to 9.9 Ma Magnetic anomalies from present to 9.9 Ma Warm colors indicate positive polarity Warm colors indicate positive polarity Cool colors indicate reverse polarity Cool colors indicate reverse polarity