8. Attenuation of compressional waves (expressed as k in: ajg/j^ = kfj^j^^) versus 

 sediment porosity in natural, saturated surface sediments ... 36 



9. Attenuation of compressional waves (expressed as k in: cedB/m ~ l^^kHz^ versus 

 depth in the sea floor or in sedimentary strata ... 37 



10. Porosity versus depth in terrigenous sediments ... 38 



11. In situ density of various marine sediments versus depth in the sea floor ... 39 



12. Shear wave velocity versus depth in water-saturated sands ... 40 



13. Shear wave velocity measured in situ versus depth in water-saturated silt-clays 

 and turbidites ... 41 



14. A summary of compressional wave velocity versus density in Hamilton 

 (1977)... 42 



PART II: ACOUSTIC MODELING 



15. Ray theory representation (high frequency) . . . page 63 



16. Wave theory representation (low frequency) ... 63 



17. Multilayer liquid model ... 64 



18. Multilayer Hnear hquid model ... 65 



19. Linear K- and constant K layers ... 66 



20. Phase comparison for linear K- and constant K models (zero attenuation 



for both models) ... 67 

 Phase comparison for lin 

 attenuation for both models 



21. Phase comparison for linear K- and constant K models using 0.05 dB/m 



8 



22. Bottom loss comparison for linear K- and constant K models using 0.05 dB/m 

 attenuation for both models ... 69 



23. Multilayer solid model ... 70 



24. Comparison of multilayer solid and liquid models ... 71 



25. 3-D plot of bottom loss as a function of grazing angle and frequency ... 72 



26. Sound speeds and ray diagram ... 73 



27. Example of Gibb's oscillations ... 74 



28. Equivalent bottom for use with the Parabohc Equation ... 74 



29. Desired values of bottom loss ... 75 



30. Algorithm to generate an equivalent sediment model with smooth K^ and 

 bottom loss ... 76 



31. Good agreement between the bottom loss for the equivalent sediment mode 

 (the line) and the desired bottom loss (the filled circles) ... 77 



