F(KHZ) 



20 30 AO 



Figure 9. Attenuation Versus Frequency 



Figure 8: Reflection Coefficient (normal incidence) versus Porosity 



L: R = 0.497 - 0.00446 



F: R = 0.647 - 0.00656 



H: R = 0.669 - 0.00666 

 Figure 9: Attenuation versus Frequency 



L: a = 0.062f - 0.154 



M: a = 0.05f 



For all these relationship plots, the linear regression coefficient (r) is at 

 least as large in absolute value as that required for a 95% assurance of linear 

 correlation (Young, 1962) . 



CONCLUSIONS 



This report describes a unique instrument for in situ investigation and sampling 

 of ocean sediments. Precise sound speeds determined with the DOSP, coupled with 

 density or porosity determined in the laboratory on the sample that the DOSP 

 provides, are the only parameters required to characterize the sediment in terms 

 of its elastic properties. This DOSP also provides a means of obtaining attenu- 

 ation of compressional sound waves in situ in sediment. Empirical relations 

 have been given whereby (to first order) sediment shear strength for high por- 

 osity marine sediments can be predicted from the precise in situ measurement of 



VII-30 



