Since no new high-explosive test data are available for determining these variables, TM 23-200 and past test data will be used as a guide. These variables are defined in the TM by three gross factors as follows: Soil Type Factors Saturated soil Washedsoil Granite or Sandstone 1.5 2 0.8 Sand 1.0 The above factors may be a guide to the limits by which craters are affected by these variables. If a more detailed analysis of the soil is made other variables such as void ratio, soil fracture in the crater vicinity, and degree of confinement can be used toward a greater accuracy in crater prediction. Until further determinations are made as to standard soil conditions, the dry soil curve as given in TM 23-200 shall serve as the standard curve, and the value of A shall be taken as 64 feet. With the exception of height of burst, energy containment, and washing, all variables are directly concerned with soil properties. The HOB factor, F,;, is determined from the standard dry soil curve contained in TM 23-200. This curve, Figure 1, shows a change in crater radius as the burst position of the device varies from the ground surface. A factor for any scaled height of burst is found by determining the . factor needed to adjust the crater radius to that of a surface burst. The accuracy of such factors would depend upon the accuracy of the TM 23-200 curve and scaling. Adjusting and com- _ paring of craters with scaled height of burst above 20 feet by means of HOB factors is not considered necessary since these craters are only shallow ground depressions. The F, factor may be denoted as a strength factor and-is probably related to the strength of the soil in compression and shear. The relationship should be sought in terms of the unconfined compressive strength since the appropriate degree of confinement is not constant, sand cannot be tested for compression in an unconfined condition, therefore, it shall be given a strength factor of one. The upper limit, then, for the F, factor is 1.0. The lower limit would be the value for hard rock, which for granite, as given in the TM, is approximately 0.8. The F; factor accounts for degree of saturation. (The degree of saturation is the percentage of voids which are filled with water and ranges from 0.0 for a dry sand to 100.0 for a completely saturated soil.) Since dry sand is the standard having a value of 1.0 the lower limit would be 1.0. The upper limit, representing complete saturation, will vary for sand or clay type soils but to be consistent with TM 23-200 a value of 1.5 will be used. The F, factor is for washing and ranges from 1.0 to 1.33 for saturated sand. Clay type soils are expected to be affected to a lesser degree by washing, and rock is expected to be affected to a still lesser degree. It is recognized that craters at the EPG have been subjected to different degrees of washing as evidenced by the existence of crater lips for some craters, An attempt will be made to assign factors for (1) complete washing to craters with no lips, (2) partial washing to craters where evidence of lip exists, and (3) no washing for craters with lips that are land locked. Another factor, F,, energy containment, can be entered into the equation. This factor will be a correction for the degree of containment of the nuclear device which resuits in the directing of more or less energy into the ground. This is a significant factor since data from two contained surface shots (Shots Seminole and Koa) in the EPG area indicate a considerable in- crease in crater dimensions with some form of tamping. A number of variables such as density and thickness of containment material, weapon design, and placementall enter into the determination of this factor. separately. It is probable that each detonation of this nature must be analyzed Another factor, F,, can be inserted for inhomogeneities that are relatively distant in com- parison to the close-in phenomena. That is, this inhomogeneity factor is a correction for such 12