Elugelab, located at the northern side of the Eniwetok Atoll. The detonation, designated the MIKE shot of Operation IVY, resulted in the following general phenomena, based on preliminary observations: a. <All of the island and portions of two adjacent ones were obliterated; a crater four-fifths of a mile in diameter and 80 feet in maximum depth was formed, (The earth shock was detected by seis- mographs in the United States, and presumably the world over.) b. The mushroom cloud rose 26 to 28 miles, with a stem roughly 8 miles in diameter and a cloud top about 40 miles across, , ¢, Radiation wes high on the islands near the detonation, but decayed sufficiently in three days to permit recovery of photographic and other scientific recordings. 3. Nearly ideal weather conditions prevailed end recovery of scientific data was excellent. Radiological conditions per- mitted manning the aircraft control tower on Parry Islend onehalf hour after detonation and ships reentered the legcon the day after the snot. The radioactive cloud drifted circuitcusly at great height for several days in the general area of the Marshelis, undergoing normal radioactive decay and being diffused and dissipated in the eir currents. Airborne rédicactivity was detected in the United States and other countries, but the concentration was low and there was no health hazard. (See map of world-wide moni- toring stations in Part VI, Biology and Medicine.) POE SoCuIve 5 ee . Direction of Thermonucleer Development 4, The detonation of prLETED be has established the feasi- bility of achteving a thermonuclear reaction in liquid Ceuteriuns on a lergee scale end of using the resultent neutrons to cause exten-