contained tables (based on the same data) of computed values of impedance, reflection 

 coefficients and bottom losses at normal incidence, and elastic properties (bulk modulus, 

 Poisson's ratio, dynamic rigidity, and velocity of the shear wave). Reproduced here are 

 regression equations for the more important and useful interrelationships between proper- 

 ties (from Hamilton, 1975d). 



In the sections which follow, frequent references will be made to the three general 

 environments: the continental terrace (shelf and slope), the abyssal hill environment, and 

 the abyssal plain environment. These environments and associated sediments were discussed 

 in greater detail by Hamilton (1971b). 



Sediment nomenclature on the continental terrace follows that of Shepard (1954), 

 except that within the sand sizes the various grades of sand follow the Wentworth scale. In 

 the deep sea, pelagic clay contains less than 30 percent calcium carbonate or siliceous material. 

 Calcareous ooze contains more than 30 percent calcium carbonate and sihceous ooze more 

 than 30 percent silica in the form of Radiolaria or diatoms. The Shepard (1954) size grades 

 are shown in these deep-sea sediment types to show the effects of grain size. 



Examples of the many scatter diagrams of interrelationships are sound velocity (at 

 one atmosphere and corrected to 23 degrees Celsius) versus sediment porosity, mean grain 

 size, and percent clay-sized particles (Figures 1, 2, 3); these are three of the best indices to 

 velocity. An advantage of using mean grain size or percent clay-sized materials as indices to 

 sound velocity is that grain size and clay size tests can be made in dried or partially dried 

 sediments in which porosity or sound velocity tests cannot be made. 



These tables, diagrams, and regression equations are basic information on which pre- 

 dictions of sound velocity and density can be based given only a sediment type or grain size. 

 The methods for such predictions were included in an earlier report (Hamilton, 1971b). 



Regression Equations Interrelating Various Sediment Properties 



Regression lines and curves were computed for those illustrated sets of (x,y) data in 

 Hamilton (1975d). These constitute the best indices (x) to obtain desired properties (y). 

 Separate equations are listed, where appropriate, for each of the three general environments 

 as follows: continental terrace (shelf and slope), (T); abyssal hill (pelagic), (H); abyssal plain 

 (turbidite), (P). The Standard Errors of Estimate, o, opposite each equation, are applicable 

 only near the mean of the (x,y) values. Accuracy of the (y) values, given (x), falls off away 

 from this region (Griffiths, 1967, p. 448). Grain sizes are shown in the logarithmic phi- 

 scale (0 = -log2 of grain diameter in milhmeters). 



It is important that the regression equations be used only between the limiting 

 values of the index property (x values), as noted below. These equations are strictly empir- 

 ical and apply only to the (x,y) data points involved. There was no attempt, for example, to 

 force the curves expressed by the equations to pass through velocity values of minerals at 

 zero porosity or the velocity value of sea water at 100 percent porosity. 



The limiting values of (x), in the equations below, are: 



1 . Mean grain diameter, M^, 

 (T) 1 to 9 

 (H)and(P)7 to 10 



10 



