I. INTRODUCTION 



A. Purpose 



In July 1961, the USS PREVAIL (AGS-20) conducted total magnetic 

 intensity, bathjmietric, and bathy thermal survey operations for the 

 U. S. Naval Oceanographic Office.* The purpose of the magnetics 

 phase of this survey was to define more precisely the characteristics 

 of the earth's magnetic field over the continental shelf, slope, and 

 adjacent deep-water area off the east coast of the United States. 



Coincident with the geomagnetic and bathymetric measurements, 

 bathythermograph observations and continuous recordings of sea 

 surface and injection temperatures were taken. These observations 

 were part of a project to develop a method for predicting the 

 ocean's thermal structure. Thermal structure data are reported 

 in U. S. Naval Oceanographic Office Technical Report 113 (in prepa- 

 ration) and are not included in this report. 



B. Background 



Several airborne magnetometer survey tracks had been flown by 

 Oceanographic Office Project MAGNET survey aircraft over the east 

 coast of the United States and the adjacent ocean area. Analysis 

 of the data recorded along these tracks indicated that a magnetic 

 anomaly is characteristically present at or near the location of 

 the continental slope. Distinct magnetic anomalies of about twenty 

 miles in horizontal extent and with various shapes and amplitudes 



*In accordance with Public Law 87-533 effective 10 July 1962, the 

 U. S. Navy Hydrographic Office was redesignated as the U. S. Naval 

 Oceanographic Office. 



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