1. Geology 360 - Introduction to Strike-Slip Faults

2. Levant Strike-Slip Faults Left-lateral strike-slip Levant fault, plate boundary between Arabia and Africa

3. San Andreas from Space San Francisco Bay, California.  Two northwest-southeast- trending faults are visible.  The Hayward Fault, bordering the urban area east of San Francisco Bay  The San Andreas Fault, crossing the mid-San Francisco Peninsula before dipping beneath the Pacific Ocean and surfacing again northwest of Golden Gate Bridge

4. San Andreas fault, western North America

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 (locked fault) Regional deformation occurs but the fault does not break (locked fault) 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 The far-field strain may limit whether the fault accommodates all the plate motion at its trace The 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 (fault is not locked) Slip occurs slowly on the fault continually over time (fault is not locked) 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 http://www.data.scec.org/Module/links/landrupt.html Landers rupture propagation movies

25. Strike-Slip Faulting: EQ’s = dislocations

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

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

29. Transtension

30. Development of a Pull-Apart Basin

31. Pull-Apart Basin

32. Initial Releasing Bend

33. Evolution of a Releasing Bend

34. Normal (-) Flower Structure - Tulip

35. Transpression

36. Development of a Restraining Bend

38. Initial Restraining Bend

39. Evolution of a Restraining Bend

40. Reverse (+) Flower Structure - Palm

41. Summary of Flower Structures - Palms & Tulips

42. Summary of Step Overs - Strike-Slip Faults

43. Los Angeles - Pull apart structure Releasing bend

44. Summary of Flower Structures - Palms & Tulips

48. Oceanic Strike Slip fault: Transforms

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

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

51. 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