



Positive 



Positive 



Season 



Total 



Gradient, # 



Gradient, % 



Fall 



82 



64 



78.0 



Winter 



115 



103 



89.6 



Totals 



197 



167 



85.0 



Spring 



140 



41 



29.3 



Summer 



172 



45 



26.2 



Totals 



312 



86 



27.6 



Table 3.9. Korea Strait sound speed profiles. 



Sediment properties for this site are given in Table 3.10. This geoacoustic model 

 was constructed by Dr. E. L. Hamilton of NOSC, Code 5031, from qualitative information 

 about the composition and layering of the sediments (Reference 10). The sea floor at the 

 site is smooth and flat. The surface sediment is a fine sand. The sediment of mud (silt-clay) 

 over the acoustic basement (assumed to be basalt) in the general area may vary between 

 about 400 and 2000 m and is modeled at 1000 m thickness here. The fine sand surface 

 sediments (modeled here to be 3 m thick) do not extend over the entire Korea Strait (Ref- 

 erence 1 1). A geoacoustic model at a location in the northeastern part of the Strait will 

 probably be nearly the same as Table 3.10 without the fine sand surface layer. 











Compressional 











Thickness, 



Depth, 



Velocity, 



Attenuation, 



Density, 



Layer 



Material 



m 



m 



m/s 



(dB/km)/Hz 



g/cm^ 



Sea Floor 









R=1.68 













Sfc 



1762 



0.5 



1.93 



1 



Fine sand 



3 



3- 



1790 



0.4 



1.93 



2 



Terrigeneous 



1000 



3+ 



1510 



0.10 



1.53 





Mud 





100 



1633 



0.11 



1.66 





(silt-clay); 





200 



1743 



0.12 



1.78 





turbidities 





400 



1929 



0.14 



1.99 









600 



2081 



0.12 



2.14 









800 



2211 



0.10 



2.35 









1000 



2330 



0.09 



2.31 



3 



Basalt 



1000+ 



4100 



2000 



0.03 



2.33 



Table 3.10. Sediment properties at the Korea Strait site. 



10. Reference available to qualified requesters. 



1 1 . Reference available to qualified requesters. 



31 



