INTRODUCTION 



In underwater acoustics studies related to undersea 

 warfare, an understanding of underwater sound transmission 

 and effects such as reverberation, attenuation, reflection, 

 and refraction is indispensable. Such knowledge is also 

 used in geophysical research; data on refraction and 

 reflection of elastic waves through and from the sea floor 

 are invaluable in determining the structure of the earth's 

 crust. 



In either of these applications, studies of the sea 

 floor are greatly facilitated by a geoacoustic model: a plan 

 and cross section of a specific geographic area of the sea 

 floor, accompanied by tables and graphs indicating those 

 properties and characteristics of the sediment, rock, and 

 water which are of importance to the behavior of under- 

 water sound. 



In the past there has been a variety of models, many 

 with a tenuous (or no) relation to any real sea floor. 

 Such models are useful in many rigorous solutions, but in 

 special applications to a particular sea-floor environment 

 it is necessary to know the outside limits of the more 

 important parameters, such as sound velocity or density. 



Geoacoustic models incorporating information gained 

 in support of underwater sound experiments and other 

 studies conducted by the U. S. Navy Electronics Laboratory 

 are to be covered in a projected series of reports, of which 

 this is the first. The models to be described here involve 

 (1) certain shallow-water portions of the Bering Sea, and 



Superscript numbers identify references listed at end of 

 report. 



