Gallagher 



core no. 6, where the sound velocity differences ore quite large. The maximum 

 differences between the measured and Sutton derived bottom losses, occurring at 

 various incident angles, for both cases ore shown in Table 7. 



Table 8 indicates the reflection coefficient values obtained from field tests 

 at a frequency of 3.7 kHz and denotes the variations in bottom loss obtained from 

 the core data relative to the field values. The bottom loss values obtained 

 from the field tests are consistently greater than those obtained from the use of 

 either method on the core samples. 



Table 7 



MAXIMUM DIFFERENCES IN REFLECTION COEFFICIENT VALUES 

 CORES NO. 5 AND NO. 6— TOTO 



Bottom Loss Difference 

 Direct Minus Sutton 



+6.6 db 

 +4,7 db 

 +6,3 db 

 +8.8 db 

 +n.5db 



-4.1 db 



+5.2 db 

 +18,2 db 



+3.1 db 

 +11.5 db 



Table 8 



VARIATIONS IN BOTTOM LOSS BETWEEN FIELD DATA AND DIRECT AND 

 SUTTON DERIVED VALUES— CORES NO. 5 AND 6— TOTO 



99 



