HORTON: THE EFFECT OF ROUGH INTERFACES ON SIGNALS 

 THAT PENETRATE THE BOTTOM 



DISCUSSION 



DR. IRA DYER (Department of Ocean Engineering, Massachusetts 

 Institute of Technology) : I understand your conclusion to be that 

 moderate roughness does not substantially affect the computations of 

 refracted paths in the bottom sediments. 



DR. C. W. HORTON, SR.: Yes. 



DR. DYER: Does this include the effect of .scattering of this 

 energy outside the angles at which you might expect to receive these 

 bottom refracted paths? 



DR. HORTON: I should have mentioned in my discussion and didn't 

 that this refraction path is essentially unique. That is to say, for 

 one configuration of source and receiver in the water there will be 

 only one path through the bottom that gives you the travel time that 

 you will see. This is borne out by the experimental data. 



The loss of amplitude I referred to represents, I believe, all 

 the data that is scattered in directions other than the refracted path. 

 So they are essentially refracted out of this acoustic bundle and don't 

 arrive at the emerging point. 



DR. DYER: And nonetheless small? 



DR. HORTON: Nonetheless small for the moderate amplitudes. 



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