1. (see also http://www.mines.edu/fs_home/tboyd/GP311/MODULES/SEIS/main.html)n Seismic Methods: Refraction

2. Seismic Waves Body Surface P S Love Rayleigh

3. Seismic Wave Speeds MaterialP wave Velocity (m/s)S wave Velocity (m/s) Air332 Water1400-1500 Petroleum1300-1400 Steel61003500 Concrete36002000 Granite5500-59002800-3000 Basalt64003200 Sandstone1400-4300700-2800 Limestone5900-61002800-3000 Sand (Unsaturated)200-100080-400 Sand (Saturated)800-2200320-880 Clay1000-2500400-1000 Glacial Till (Saturated)1500-2500600-1000

4. Reflection and Refraction sin  1 = sin  3 = Vp 1 Vs 1 sin  2 = sin  4 = Vs 2 Vp 2 p (ray parameter)

5. Critical Refraction

6. Seismic Refraction Waves passing from slow to fast medium

7. Reflection & Refraction 0 200 400 T, msec Direct Reflected Refracted

8. Refraction Analysis (flat): Velocity estimation

9. Depth from TT curve

10. Structure from TT curve

11. Refraction: One layer case

14. Refraction: 3 layer case

19. Engineering Quad 1/27/00 12 gauge source 1m geophone spacing, 1 m minimum offset

20. Data from Treman (11/2/05)

21. Engineering Quad 1/27/00 12 gauge source 1m geophone spacing, 1 m minimum offset SHOT *

23. Seismic Raytracing (forward modeling) http://www.scielo.cl/scielo.php?pid=S0716-02082003000100006&script=sci_arttext&tlng=en