Gallagher 



Table 4 



VARIATIONS IN BOTTOM LOSS BETWEEN FIELD DATA AND DIRECT AND 

 SUTTON DERIVED VALUES—CORES NO. 1 AND 2— HAP 



Incident 

 Angle 



42° 

 50° 

 55° 

 57° 

 60° 

 62° 

 65° 

 68° 

 70° 

 75° 

 80° 



Field 

 Values 



8.0 db 



9.1 db 

 5.0 db 



6.0 db 



4.4 db 

 1.8 db 



3.5 db 

 1.8 db 



3.1 db 

 0.8 db 

 3.1 db 



Core No. 1 



Field Minus Field Minus 



Direct Sutton 



+2.5 db 

 -1.2db 

 -0.3 db 

 -4.4 db 

 -4.7 db 

 -3,9 db 

 -2.6 db 

 -9.9 db 

 -3.8 db 

 -4.4 db 

 +1.8db 



+6.7 db 

 +3.6 db 

 -0.2 db 

 ^.3 db 

 -1 .6 db 

 -4.4 db 

 -2.0 db 

 -3.6 db 

 -3.3 db 

 -6.7 db 

 -1 .0 db 



Core No. 2 



Field Minus Field Minus 



Direct Sutton 



z(.io'l 



46 48 50 52 54 56 58 60 52 54 56 58 60 62 64 66 



TONGUE OF THE OCEAN (TOTO) 



In contrast to the large differences noted between the Sutton derived and 

 directly measured sound velocity values In the Hatteros Abyssal Plain cores, the 

 differences between these values in TOTO core no. 5 are small . These data, 

 which are shown in Table 5, present an 

 interesting example of the caution that 

 should be exercised in using this model 

 for predicting in situ bottom losses. 

 Small differences in sound velocity be- 

 tween In situ values and those deter- 

 mined from direct core measurements 

 could be produced by mechanical dis- 

 turbances in the sampling and handling 

 processes. These differences would be 

 produced by the alteration of the sedi- 

 ment aggregate structure. It may be 

 assumed that these differences would be 

 of the same magnitude as the differences 

 reported for core no. 5 In Table 5. 



Fig. 5 



Vertical Acoustic Impedance Profiles — 



Core No. 5 -TOTO 



The acoustic impedance profiles constructed from the data from these two 

 methods are shown in Fig. 5. Changes in the magnitudes of the Impedance layers 



96 



