MASS DISTRIBUTION AND THROWOUT STUDIES

Analysis of data on distribution of ejecta on the ground surrounding a nuclear crater collected at 117 sampling stations indicates that areal density varies inversely as distance raised to the 4.3 power. Circumferential variation in areal density was significant along all sampling rings; the ratio of highest observation to lowest was 37, 7, 10, and 32 at incremental distances in crater radii of 3.5, 4.7, 7, and 9.3 respectively. The total ejecta mass represented about 58% of the mass inferred from the apparent crater volume suggesting that about 37% of the crater volume was caused by compression of the surrounding desert alluvium. One half of the total mass of material ejected was deposited between the crater edge and two crater radii, whereas 97% of the total ejecta mass was deposited within ten crater radii. The ejecta profile exhibited a two- layer system, the lower layer consisting of the fine material ejected in mass or bulk. The upper layer consisted of larger particulate materials which were subjected to atmospheric infiuence when ejected along their ballistic trajectories. The missile-like material in the upper layer and the discrete masses of alluvium which reated hundreds of impact craters probably were deposited late in themore » time history of ejecta deposition. (auth)« less