RMI Nuclear Justice Documents

From this point of view, one might simply expect that both the depth and width of the crater near Ground Zero. At the same time, the cra- crater would be-proporfional to the energy transferred to the ground. In the absence of detailed studies involving many yields at many different pressure ratios and soil characteris- flatness to the crater occasioned by the relative propagation velocities for the shock in air and soil from which one would expect the crater profile to be concave upward, as in Fig. 1.1. On tics, the results of Fig. 8 of LA-1529 are some the other hand, the presence of fissuring in the should scale like W'%; thus the volume of the - assurance, if meager, that in a homogeneous soil similarity scaling might be expected to hold. We might reasonably expect the crater ra- ter represents a compromise between other competing mechanisms. Thereis a general Atoll structure suggests that the shape of the crater could be concave downward near the center if a sink hole develops. Superimposed on sort of threshold below which no deformation these competitive mechanisms is the final downward movement of material in the crater toward the center, as in reaching a stable angle of repose. This leads to the expectation that at Eni- the ground shock is principally controlled by the air shock, then the samevalue of pressure oc- reasonable as any for a general description. dius té scale like W™ for the following reasons. The soil displacement probably involves some takes place. If, as in the case of strong shocks, curs at distances like W'?. The crater depth presents a different aspect. At these high pressures it is believed possible for the soil to movein plastic flow, which probably implies that the movementof the soil is not simply a function of the peak pressure but is probably a strong function of the pressure duration as well. The Atoll structure suggests that such flow is possible at Eniwetok, and one could therefore expect relatively deeper craters than those which would be indicated by similarity scaling alone. Near Ground Zero then, even though the depth to which a given pressure will occur scales as W", this pressure exists for a time which is W‘5 times longer on the larger bomb. This suggests that the depth of the crater near Ground Zero might behave more readily like W™ rather than W'?. On tower shots there is some jetting down the tower legs, which constitutes a preferential transmission of energy in the region immediately surrounding the tower, and suggests a somewhat deeper crater wetok the model of the crater as a conical section (straight-line profile) is probably as From the foregoing considerations, we as- sume that the crater is a conical sectionof radius proportional to W’? and depth proportional to W%; thus the volumeis vena Raw where R is the radius of the crater and d is the maximum depth at Ground Zero. We also recognize this as a crude description at best. REFERENCES 1, F. B. Porzel, Soil Pressures and Energy Transfer on Mike Shot, Los AlamosScientific Laboratory Report LA~1529, October 1952. 2. B. Suydam et al., Greenhouse Handbook of Nuclear Explosions, Greenhouse Report, Vol. II, WT-103, p. 29, March 1951. 3. F. B. Porzel, Thermodynamic Properties of Air, J-Division, Los Alamos Scientific Laboratory, fertember 1951.