Bottom loss models that account for gradients ... 49 



Liquid multilayer model ... 49 



Linear gradient multilayer model ... 50 



Comparison of the two models ... 5 1 



Sohd multilayer model ... 52 



Calculation of R for many solid layers using Knopoffs method ... 53 

 Comparison of multilayer solid and liquid models ... 56 

 Effect of bottom interaction on the sound field ... 56 



Equivalent sediment layers for use with the P.E. model ... 57 

 Summary ... 58 

 References ... 60 



TABLES 



PARTI: MARINE SEDIMENT PROPERTIES 



la. Continental terrace (shelf and slope) environment; average sediment size 



analyses and bulk grain densities . . . page 26 

 lb. Continental terrace (shelf and slope) environment; sediment densities, 



porosities, sound velocities and velocity ratios ... 26 

 2a. Abyssal plain and abyssal hill environments; average sediment size 



analyses and bulk grain densities ... 27 

 2b. Abyssal plain and abyssal hill environments; sediment densities, 



porosities, sound velocities and velocity ratios ... 28 



PART II; ACOUSTIC MODELING 



3. Input parameters to the solid multilayer program . . . page 62 



ILLUSTRATIONS 



PART I; MARINE SEDIMENT PROPERTIES 



1. Sediment porosity versus sound velocity, continental terrace (shelf 

 and slope) . . . page 29 



2. Mean diameter of mineral grains versus sound velocity, continental terrace 

 (shelf and slope) ... 30 



3. Percent clay size versus sound velocity, abyssal hill and abyssal plain 

 environments ... 3 1 



4. Sonobuoy station locations in the Bay of Bengal and adjacent areas as revised 

 from Hamilton et al (1974) which contained only Antipode and Circe data ... 32 



5. Instantaneous velocity, V, and mean velocity, V, versus one-way travel 

 time in the Central Bengal Fan ... 33 



6. Average of linear velocity gradients, in meters per second per meter, versus 

 one-way travel time, t, in seconds ... 34 



7. Attenuation of compressional (sound) waves versus frequency in natural, 

 saturated sediments and sedimentary strata ... 35 



