English: Fallout pattern from the 3.53 Mt total yield (15% fission yield) Zuni nuclear test, a coral island surface burst at Bikini Atoll, 1956. The prediction of fallout shown for comparison is from Edward A. Schuert's U.S. Naval Radiological Defense Lab. 1957 report USNRDL TR-139, A Fallout Forecasting Technique with Results Obtained at the Eniwetok Proving Grounds . Source: Philip D. LaRivere and Terry Triffet, Characterisation of Fallout, Operation Redwing, U.S. Department of Defense, Weapon Test report WT-1317 (1961), declassified online version at http://worf.eh.doe.gov/data/ihp1c/0881_a.pdf The measurements for the contours are in Roentgens per hour of gamma radiation, as extrapolated back to the standard reference time of 1 hour after detonation (before most of the fallout was actually deposited). The data have also been converted to land-equivalent dose rates, which at 2 days after burst were 535 times the measured levels from fallout dispersed in the water above the thermocline [1]