Abstract

A continuous record of variations of the total magnetic field intensity was taken along a single flight line from Adak, Alaska to Kwajalein, Marshall Islands, on Project Volcano during the summer of 1947. Anomalies as large as 750 gamma extending over distances of 20 to 30 mi were found over open ocean areas between Adak and Midway, where ocean depths range from 2000 to 3000 fathoms. A rather complete survey, at an altitude of 1500 ft above sea level, was made over Bikini Atoll and the adjacent seamount. A broad negative anomaly of 750 gammas was recorded over Bikini, with several superimposed more localized anomalies; those associated with the adjacent seamount were larger than those associated with Bikini.