Aeromagnetic maps and second vertical derivative maps of Great Sitkin Island, Northern Adak Island, and part of northeastern Umnak Island, Alaska

The eight attached maps were constructed from data taken on Project Volcano in the summer of 1947. The project was sponsored by the Office of Naval Research and conducted by the U.S. Geological Survey in cooperation with the Naval Ordnance Laboratory. Field work was done by Fred Keller, Jr., and J. L. Meuschke, Geophysicists of the U.S. Geological Survey, and by L. R. Alldredge, Physicist of the Naval Ordnance Laboratory. The instrument used was a modified AN/ASQ-3A flux-gate type total field magnetometer mounted in the tailcone of a PBY-5A aircraft. It is hoped that observation of the magnetic fields over volcanic areas over a period of years, may lead to prognostication of volcanic activity. These maps represent the results of the first of such surveys.