| r Description and History: 1526-1972 . 57 b, Large craters were formed on the reefs on the north end of Runit, to "the Northeast of Bokinwotme (Edna) where Elugelab and Lidilbut had been, und on Boken (Figures 1-55, 1-56 and 1-57), by Surface profiles in the vicinity of ground zeroes were changed " blasts as well as by efforts to restore the area for continued use. eas. Coconut palms and other vegetation were destroyed in manyar of “The construction of causeways, landfills, and the excavation borrow areasin the course of test preparation had modified the atoil topography. Large structures and bunkers for test measurement or observation remained after testing was completed. _ Semipermanent buildings were left standing, especially on the islands of the southeast. | h. Tons of concrete and metal debris remained. Conditions that were not readily visible included contaminated soil on manyislandsof the atoll and contaminated sediments on the bottom ofthe lagoon. The lagoon also contained many miles of cable that had beenlaid between islands for instrumentation, communication, and the activation of the nuclear devices. The principal radioisotopes that made up the residual radioactivity on Enewetak Atoll following the test period were: 4. Cobalt-60, an emitter of gamma rays and beta particles, with a half- FIGURE 1-55. CRATERS ON RUNIT. ST SS eee