places certain requirements on the medium. poses of crater investigation, At a minimum for the pur- it is required that the properties of the medium at equivalent locations (scaled) in two exper identical. & must be This requirement is cémpletely met if thetwo media are homogeneous, isotropic, and identical. The 7 getfes of earth, how- ever, are greatly affected by cverourdened#tieere: Thuseisasate sense the properties of eartn are-efdssly dependent on actual (not scaled) deptn below tne surface, Bhd in a dynamic sense these properties will be similarly affected by the oressure produced by the explosion. Thus one of the fundamental conditions for the proper application of simple scaling laws is violated. The greater the range of size of explosion, and hence of depths, the more serious this violation becomes. A further difficulty with the application of theory occurs in situations such as existed on CASTLE, where two media, earth and water, were involved, and where the earth was saturated so that forces were transmitted by a complicated combination of intergranular forces and hydraulic pressures.