EWING: ACOUSTIC PROPERTIES OF THE SEA FLOOR 



sort which seem to be present every time you get to the geometry 

 corresponding to low grazing angles. 



So there are still possible complications I think that need to 

 be properly considered even if you tried to improve the experimental 

 range. 



DR. J. L. WORZEL (Marine Science Institute Geophysics Laboratory) 

 I think John Swing's answer to Al Sykes ' question needs a little mod- 

 ification. The oozes on the bottom act like a liquid when they have 

 high porosity, but as they get buried deeper the porosity is reduced 

 and then they no longer act like that. 



DR. SCHULKIN: One of the questions is: What is the sound speed 

 and absorption as a function of porosity? Also, how does porosity 

 vary with depth beneath the surface of the bottom? When do shear 

 waves start in? 



MR. EWING: Well, we know very low velocity shear waves can be 

 developed in very short sediments. We have observed them. 



DR. HANNA: I have a question related back to the problem of 

 the scatter of the data you referred to. Just to make sure that I 

 didn't misinterpret some of the things that you said before, I would 

 like to go back and refresh myself. 



I thought I understood you to say that if G is of the order 1 

 per second then K is of the order of 2? 



MR. EWING: More or less, yes. 



DR. HANNA: Then the question I have refers to the accuracy of 

 the resolution in time that you can achieve for the one-way travel 

 time. 



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