BOMBS AT BIKINI 



The waves multiplied as they progressed. Near the 

 column there were few of them, but as they approached 

 Bikini beach, they were a family of fifteen or twenty. 

 Each wave gathered height as it entered the shallow 

 water off Bikini, three and a half miles from the Zero- 

 point; it drew itself up into a short, steep, plunging 

 breaker. Maximum height of the breakers was fifteen 

 feet. 



The uprush was not particularly severe. The water 

 rushed up over the beach top, in many areas, and 

 caused some flooding and erosion. Thousands of tons 

 of beach materials were moved. Several medium-sized 

 beach landing craft and small boats were damaged and 

 a few huts also. But no noteworthy damage resulted.* 



The ^'backrush" from the first wave swept more 

 than 50,000 tons of beach sand into the lagoon. 



The explosion produced much erosion of the lagoon 

 floor directly beneath the bomb. The amount of bottom 

 material wrenched free was of the order of a million 

 cubic yards. The main crater formed was not entirely 



* Maximum water height on Bikini Island was measured hy two 

 kinds of height gages: tin-can gages and electrical-fuse gages. The 

 tin-can gage consists merely of a tall pole securely mounted ver- 

 tically and carrying a number of tin cans at various heights. Each 

 can is upright; it is open at the top and has a small awning to keep 

 out the rain. If a wave covers the ground to a depth of, say, four 

 feet, then all cans helow the four-foot level are filled with water. 

 In the electrical-fuse gage, the tin cans are replaced hy wires having 

 small gaps. When the water rises enough to immerse a gap, an elec- 

 trical current flows and a small electrical fuse is blown out. From. 

 inspectio7i of the assembly of fuses, maximum water height can be 

 deterynined easily. 



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