DESCRIPTION OF THE MARINE ENVIRONMENT 79 



AND OCEANOGRAPHIC PROCESSES 



ments, rocks, and habitats for bottom-dwelling organisms permits 

 estimation of biological noise and magnetic background, in the 

 absence of direct observation and measurement of these factors. 

 The selection of sites for submarine instrument arrays or mine- 

 fields is dependent upon knowledge of the form and composition 

 of the bottom. 



Studies are made of various ocean areas showing the relief of 

 the ocean bottom, the materials covering it, and the nature of the 

 crustal and subcrustal layers beneath the sea floor. Also, 

 earthquakes, volcanic eruptions, and tsunamis are charted in an 

 effort to determine their effect on the marine environment and 

 on military operations. A Navy stndy of St. Paul Rocks was 

 used as background material in planning the MOHOLE project; 

 marine geology studies were important factors in the search for 

 the submarine THRESHER and for the lost nuclear bomb off 

 Palomares, Spain. 



A file of about 150,000 descriptions of bottom samples is con- 

 tinually being enlarged and is currently being automated. Files 

 on volcanic activity and tsunamis are also maintained. Future 

 plans call for procedures to retrieve required data for specific 

 places on demand. 



CURRENTS 



The U. S. Navy has had a long-standing interest in ocean current 

 data for use by the defense establishment and the merchant marine. 

 As previously described, formalized work in systematizing current 

 observations dates back to Lt. Maury's "Wind and Current Chart 

 of the North Atlantic", published in 1847. This early effort has 

 evolved into modern-day Pilot Charts, published in cooperation 

 with the U. S. Weather Bureau, and many other publications. 

 Detailed and accurate current charts and atlases are required not 

 only by the Navy in its operations in war and peace but also, 

 under the statutory mission of the NaVy, for the merchant marine. 



Major publications issued during the past few years are the 

 tides arid currents section of the Oceanographic Atlas of the North 

 Atlantic Ocean and the Environmental Atlas of the Tongue of the 

 Ocean. Several smaller oceanographic publications have been 

 issued covering ocean currents in such localities as the Arabian 



