388 



SECONDARY PRESSURE WAVES 



only reasonably comprehensive set of results at the time of writing is 

 from a series of measurements performed at Woods Hole. In these 

 tests, 300 pound TNT charges were fired at various depths in approxi- 

 mately 100 feet of water (the period and migration data from these 

 tests are given in section 8.11). The results (103) give, within rather 

 large limits of error, a good indication of the effects to be expected for 

 large charges and so will be described in some detail. 



In these tests, three tourmaline gauges were positioned at depths of 

 twenty, fifty, and eighty feet below the surface. The experimentally 



CVJ 



c 



100 



50 





GO 



?33P:^--^ 







T60 



20 FT. 

 O 



-^_3__ 



300 

 250 



s 



^-0. 



120 

 80 





 200 



160 

 120 

 80 

 40 



/<to 



-0~-^ 



XT 



-oo- 



Logo o% 

 o ^- 



o ^^ 



50 FT. 



420 

 320 



"^ 

 ■^ 



^ O 



o 9 o o 



op 



j)^- ^^ 



f o QqO 



Q) C^O 



c 



Q ^^ 



o ^ 



SOFT. 



^^' 



-^I — O^ 



500 

 400 



~X) O 



-^-i/ 



o^ 



100 



80 



60 



40 



20 



DEPTH (FT) 



Fig. 9.9 Observed peak pressure 60 feet from 300 pound TNT charges fired 

 in 100 feet of water. 



