developed from Figure 10 for six different yield weapons and for two different burst heights above the ground and indicates the percentage of fall-out to be expected in these cases. TABLE 2 Ht.of Burst Yield (feet ) 1k? 50 1K 5 KT 5 kt 10 KT 180 Radius of Fireball] 28 % Fell-out Relative to That From a Surface Burst 50 180 -56 25 50 340 015 67 50 460 460 222 ell 75 100 50 kT Fireball (ft) Height of Burst 100 100 10 kt Radius of 340 30 48 57 50 kT 100 50 870 -06 86 500 xT 500 KT 50 100 2200 2200 02 205 95 89 50 2900 -02 ° 95 1000 KT 1000 KT 100 870: 12 2900 203 73 95 An uncertainty of great potential importance exists in the current state of knowledge regarding the maximum dose rate intensities that are likely to be encountered on the ground following a true land surface burst. This uncertainty exists because only one nuclear detonation has occurred thus far on a true land surface, and this one experience was for the relatively low yield of 1.2 kilotons at Operation JANGIE. A crater and lip dose rate of 7500 r/hr at H+l hour was recorded after this shot. Although scaling laws would predict an increase in crater and lip dose rates with increase in yield, such higher dose rates have not been observed following the large yield surface detonations at IVY and at CASTLE; instead, the highest well substantiated dose rate readings at 1 hour after burst for any of these shots appear to lie in the range of 5,000 to 10,000 r/hr. Some have theorized that this is due to ' the fact that the crater lips have been washed by waves and that the 48