(NAVAJO) Project 2,62 = Fallout Studies by Oceanography Methods - F, D. Jennings OBJECTIVES To measure the fallout radioactivity and its chemical nature in water from a surface water burst. To calculate the equivalent land fallout pattern. To understand the nature of the transport and dilution of radio- active fallout material in the ocean to permit future surveys to acquire a complete fallout picture, DESCRIPTION AND EXPERIMENTAL PROCEDURE SIO installed and maintained thriteen deep-moored skiff stations in the fallout area between 10 and 30 miles from ground zero. Recording ~ instrunents were installed on two of these skiffs to measure radio-~ activity as a function of time at depth intervals of 20 meters down to 100 meters. The recorder was started on arrival of fallout by a trigger which was pre-set to start when radiation levels reached 30 mr/hr. Two high speed vessels, USS SILVERSTEIN (DE 534) and USS MC GINTY (DE 365), were outfitted with devices for measuring radioactivity as a function of depth and in air, and drogue floats for marking areas of particular interest. These two vessels were stationed outside the fall- out area during the shot and then proceeded to survey the fallout area, making measurements out to about 180 miles from ground zero and across a pattern about 120 miles wide. These two ships, together with the M/V HORIZON, collected about 85 water samples from the surface and from depths for Project 2.63 and an equal number for Project 2.6. The two project 2.63 YAG's were supplied with detectors for measuring and recording radioactivity as a function of depth and in addition the YAG 39 was supplied with a similar detector for use in her decay tank for COP:ED/DOE CaM oeRC ~3i 2 a