th A. Crater Size Produced by Superweapons In ore + to make a start in evaluating whether superweapons can effect the c!..1uate, an estimate must be made of the amount of material they eject by stuacying the crater size, Preliminary Report of Operation Jangie (2) gives the apparent crater volume of the underground shot as 57,000 cubic yards and that for the surface shot as 2140 cubic yards. gineering Research Associates (9) reported that the ratio of true crater depth to apparent crater depth is 1.782 for underground and 1.715 for surface when 320,000 lbs. of TNT was exploded on the surface or 35 ft. underground at Dugway Proving Ground. This indicates that the true creter volumes for the Jangle underground and surface shots should be approximately 73,000 and 3670 cubic yards respectively. B. Percent of Crater Material Present in the Atomic Cloud At the present time there is no adequate method of calculating the amount of dust that will be sucked up into the cloud when superweapons are exploded on the surface or underground. However, an attempt will be made to evaluate the order of magnitude of the material sucked up in an atomic cloud in order to determine whether there is a possibility of superweapons affecting the climate of the world. (1) Percent of Material Deposited on Lip or Returned to Crater It was thought that some information could be obtained by noting .2 amount of material returned to the crater and that deposited on the lip. 57% of the true crater volume was returned to the lip or crater in the underground Jangle Shot while the amount returned during Jangle Surface shot was 50%, An attempt was made to determine the total amount of fall-out beyond the lip of the crater, but the fall-out was found to be assymetric and the information available (5) was inadequate. It should be noted that when an attempt was made to calculate the amount of material thrown out during HE tests at Dugway (8) by subtracting from the true crater volume the volume of material that fell back into the crater and onto the lip, the volume came out negative even when allowance was made for density differences. This is apparently due to the fact that the lip consists of both fall-out and push-out material. In view of the unknown value of the push-—out material, this approach to the problem was abandoned. (2) Particle Size Distribution in the Throw-out Sail Analysis of Jangle area at Nevada Proving Grounds (5) shows that approximately 5 to 10% of the soil has diameters of 2 microns or less. However when the soil was elutriated (Sa) and collected on molecular filters, it was shown that 76% of the particles were 2 microns in diameter or less (see Table I for more detailed analysis of Particle Size Distribution). A study of the Particle Size in the cloud from TNT explosions at Dugway Proving Ground shows that 97% of Particles are less than 2 microns, 94% are less than-1 géorer-end approximately 25% are less than 0.2 microns. 4 C2=22190 Bouton