for the traverses indicated. It will be noted that the east-west profile particularly shows that the slope of the lip is very slight and that there is almost no elevation above the original g@round level. As @ result of this gentle slope the radius at original ground level becomes difficult to determine and very sensitive to elevation errors in the contour maps. ) ' The upper part of Fig. 3.10 is a map of the Shot 3 area showing the traverses made by the ship while the data for the profiles were déting’ taken. The profiles are shown on the bottom of Fig. 3.10 and Figs3. ii... Mark numbers are shown on the traverses and on the profiles. It is to be noted that the survey of Shot 3 was made 24 days after the shot itselr and that the wave produced by Shot 4 had completely inun- dated the lip of the Shot 3 crater. Because of the high level of radioactivity it was, not possible to accomplish any survey of the abovewater portion of the crater and consequently the diameters and the height of the lip at the original ground level are subject to some uncertainty. 305 . sHoT 4 Figures 3.12 and 3.13 show a similar map end profiles of the Shot 4 area. Again the numbers on the figures correspond to mark numbers taken during the survey. As noted in section 2.3.2, becauseof the interference of other activities on the day the survey was made, it was not possible to run diametral:traverses and, as shown on Fig. 3.12, the chord traverses actually depart5from the center rather far. For this reason a diametral profile, ABCDE, has been estimated from the results - of the three chord profiles shown...Prior to the shét the lagoon floor at the shot point was at a depth or:“162 ft. The bottom in the vicinity was quite irregular, with a gene } lope toward the center of the lagoon and with a large number of coral eels... The post-shot survey indicated that the effect of the shot was to pulvefize or depress the bottom directly under the shot point and to destirpy the coral heads in the vicinity. Mud or fine (almost suspended) sand) was deposited as indicated in the profiles at a uniform depth of about 180;ft. Lead line soundings by H&N during the placement of the barge for alater shot gave a depth of 250 ft. fi 3.6 COMPARISON WITH OTHER SURFACE SHOTS is ii On Fig. 3.14 crater radius is plotted as a function of yield (log scales both ways) for all surface shots for which data’are readily avail- able. These data include 256 1b TNT charges in clay and~silt-gravel at Utah and Nevada, together with similar charges in wet clay and sand at Camp: Cooke. All the other points are nuclear explosions “ranging from the JANGLE surface shot in Nevada to CASTLE Shot 3, IVY Mikel,’“and CASTLE Shot 1 in the Pacific. Thus, the points plotted includea‘wide variation in soil characteristics and an extremely wide variation in yield. It is particularly to be noted that no account nas been taken of the gross difference in energy partition between TNT and nuclear explosives. While the points plotted (with the single exception of the 26