1. SOEE2102 – Geophysical Field Trip and Tutorials Malham Tarn (North Yorkshire) October 2009 Refraction Analysis Sebastian Rost University of Leeds 2009

2. Traveltime Curves

5. Peaceful Nuclear Explosions

6. Traveltime Curves

15. At critical distance: r = 90   i c = critical angle

16. Courtesy of M. Thorne (Univ. Utah) Seismic Wavefield and Seismic Raypaths

17. Traveltimes Direct wave: (from velocity = distance / time ) x

18. Refracted Wave: Snell’s Law

19. Different ways to express the refracted traveltime curve Intercept time

20. Crossover distance: T direct = T refracted X cross > 2z

21. Field Experiment

23. Shot point geometries 12 element geophone spread Possible shot point locations

24. Off end reverse shot

25. Sat On end Forward

26. Sat On end reverse

30. Traveltime picks (from Claritas)

31. Traveltime Curves