» Associated with the greater yield of Mike, which was dozens of times greater than previously experienced, was a corresponding increase in the fallout radiation. Contrary to expectations, the winds prevailing at the time were. from the south or southeast ,~and so most of the radioactive debris fell on the open seas to the north and northwest. on the northern islands of the Atoll. Nevertheless, fallout did occur Since these islands continued to be uninhabited, no harm resulted to humans from this local fallout. U.S. tests were conducted only at the Nevada Proving Grounds in 1953, thereupon starting the pattern of tests entirely at the Nevada Proving Crounds or the Pacific Proving Grounds, each on alternate years. The next series of tests in the Pacific was in 1954 under the name Operation Castle. It involved a task force, which retained the number Task Force Seven of the 1947 forcé. Five out of the six tests in this series were at Bikini Atoll, which had “not been used for nuclear tests since 1946. The 15-megaton thermonuclear tests Bravo in this series was conducted on the surface in Bikini Atoll on 1 March 1954.4.10 The radioactivity of this.Bravo event was particularly troublesome by unexpectedly being carried to the east, rather than to the north as had been foreseen. Harmful amounts of radioactivity fell out on the inhabitedatolls of Rongelap Ailinginae, and Rongerik and on the Japanese fishing ship Fukuryu Maru. These events resulted sharply renewed interest in radiological consequences, with principal focus on the Bikini series of tests. The Atomic Bomb Effect Research Commission. which had been established after the atomic bombing of Japan, became involved. The Shunkotsu Maru of the Japanese Fisheries Training Institute cruised the Marshall Island area for survey purposes; this was followed by a U.S. cruise on the Coast Guard Cutter Roger B. Taney under the name Operation Troll. 9.7MelvinPoKlein. "Fall-Out Gamma Ray Intensity" 10. Report, UCRL-5125, (1958) Reference 1, p 165. 4 Lawrence Livermore Laboratory “) v|