1. Reflection Amplitude

2. Vertical Incidence R = A r =  2 v 2 –  1 v 1 = Z 2 – Z 1 A i  2 v 2 +  1 v 1 Z 2 + Z 1 AiAi ArAr AtAt T = A t = 2  1 v 1 = 2 Z 1 A i  2 v 2 +  1 v 1 Z 2 + Z 1  v= acoustic impedance

3. Non-vertical incidence Zoeppritz’s Equations

4. Spherical Divergence Anstey (1977) A  1/r = 1/(Vt) >>> 1/(V 2 t)

5. Transmission Loss A 0 = 1 R1R1 (1-R 1 ) (1-R 1 ) (1-R 2 ) (1-R 1 ) R 2 (1-R 1 ) (1+R 1 ) R 2 = (1-R 1 2 )R 2 = (TL) R 2 R1R1 R2R2

6. Anelastic Attenuation A  e -  r  =  f Q V f = frequency Q = quality factor V = velocity  = attenuation coefficient

7. Amplitude Factors

8. Fresnel Zone R f = ( z/2) 1/2 = (V/2)(t/f) 1/2 S&D, 1995 KB&H, 2002

9. Amplitude and Reflector Curvature S = 1 S flat 1 - r w /r i S = 1 S flat 1 - r w /r i S = amplitude from curved reflector Sflat = amp from flat reflector r w = radius of curvature of wavefront r i = radius of curvature of reflector 3D 2D Anstey 77 “Brighten Up” Ratio “focussing”

10. Fresnel Zone in 3D

11. Sideswipe

12. More Focussing Gas “lens” Wedge

13. Waveform Interference (thin beds)

14. Amplitude and Tuning S&G 95

15. Amplitudes and Gradients Neidell