1048 THE BELL SYSTEM TECHNICAL JOURNAL, SEPTEMBER 1957 



gation of currents and circulation; study of the geology of the earth's 

 crust under the ocean; and investigation of biological factors. 



In designing, in finding the best route for, in laying, and in repairing 

 a submarine cable system one can benefit from as detailed a knowledge 

 of the ocean floor as can be obtained. However, the vastness, complexity, 

 and inaccessibility of the ocean bottom make its study difficult. One 

 must depend on limited data, interpreted with the aid of a knowledge of 

 the earth sciences. The acquisition of specific engineering information is 

 further complicated by the inaccuracies of much of the existing data, 

 and the rudimentary nature of many present theories. Yet, by culling, 

 codifying, interpolating, and interpreting the data gathered during the 

 past hundred years, much can be learned that is applicable to particular 

 cable routes. Further, methods now exist for surveying and describing a 

 route with a thoroughness and accuracy that will permit many refine- 

 ments ui the engineering of future submarine cable systems. 



In this paper specific problems of immediate interest in the engineer- 

 ing of submarine cable systems are discussed in order to give a perspec- 

 tive of the use of such data in current applications. Emphasis is placed 

 on the state of existing knowledge and on the accuracy of available data. 

 The work reported forms a foundation for more detailed studies of spe- 

 cific routes and for the application of knowledge which will be derived 

 from rapidly expanding oceanographic studies to the particular problems 

 of submarine cable systems. 



1.2 Application To Submarine Cable Systems 



How are oceanographic information and technique applied in the se- 

 lection and description of the detailed path of a new cable? First, vari- 

 ations on a direct route must be examined to avoid ocean bottom condi- 

 tions which may result in cable failures. Studies of telegraph cable fault 

 records indicate that many of the deep sea cable breaks occur where 

 cables pass over sea mounts, canyons and areas susceptible to turljidity 

 currents, and an effort must be made to avoid such hazards. Topographic 

 studies form the basis for both initial route selection planning and for 

 a preliminary description of the selected route. 



This description will include, where data are available, an exag- 

 gerated depth profile uncorrected for angle of the sound beam of the 

 sonic depth recorder, a corrected 1 :1 depth profile where necessary, 

 and a temperature profile. Also, bottom characteristics, including photo- 

 graphs, can be collected for the particular route. These data will be 

 essential in planning a detailed survey of the route, and they will provide 



