such as strength, saturation, and void ratio and to determine effects of these parameters on crater size. In the absence of more refined testing, and for the purpose of moreclosely relating EPG data in this report, the following assumptions and factoring systems will be used. The assumed. standard conditions are: (1) homogeneous dry sandy soil; (2) zero height of burst, i.e., the center.of gravity of the charge at the ground surface with the lower part of the charge in full contact with the cratering medium; (3) spherical charge; and (4) 1-kt yield. _ Sealing for crater radius is based on cuberoot scaling; i.e., the radius varies directly as the cube root of the yield (or charge weight) R = aw“ for scaled HOB Where: R = radius in feet W = yield in kt A = constant This is a straight line with a slope of one third when plotted on log paper; i.e., log R = logA + Y, log W with A the intercept for a yield of 1 kt at the surface. Although deviations from cube root scaling may exist for variations in yield and height of burst, cube root scaling is assumed to hold for all materials (sand, clay, rock), conditions of materials (saturation, compaction), and heights of burst, then only the intercept (A) will be changed witha change in materials or height of burst, and a family of lines which are parallel to the standard line will exist. It becomes necessary to introduce factors by which the intercept (A) can be modified in order to reduce all data to the standard line: Thus R = /(F,, Fz, -- Fy) AW V4. Since the precise nature of the function is not known, it will be assumed as R = F,F,--F,AW™’. There remains the problem of finding the variables, defining them with known tests and relating them to the crater radius. It is assumed that the values of these factors can be determined independently of each other. 11