77 



3- 15 cps 

 High Sensitivity 



3-15 cps 

 Low Sensitivity 



30- 200 cps h 



500- 3000 cps L 

 High Sensitivity I 



500- 3000 cps I 

 Low Sensitivity I 



30-3000CP6 

 Low 

 Rodio 



Bottom 



Refracted 



Waves 



Water-borne 

 Waves 



,f^l 





-tlf,i^M'* 



Sensitivity r I I liiii| i il ljltplM ^^ 



I RBceivir — ' 



Shot mttont 



Time in Seconds 



T~ 



COMPLETE RECORD OF A l-LB CHARGE, 40 KM DISTANCE 

 Bikini Lagoon 



4 lbs, 34.6 km 

 Bikini Lagoon 



20 lbs, 22.8 km 

 SW of Statton K' 



LOW FREQUENCY CHANNELS ONLY 



SOItw, 610 km 

 NW of Station J 



Deep Water 



Fig. 14. Sample oscillogram of seismic refraction shots in Bikini Lagoon and 

 in deep water outside Bikini Atoll. 



38 95 90 80 60 40 ZO 10 S i 



X greater than indicated level 



Fig. 15. Cumulative distribution of 

 low-frequency noise spectrum levels 

 observed in the North Equatorial Pacific. 



Chargt Wtifht W tn lbs 



Fig. 16. Maximum range of detection 

 of beginning of the bottom refracted 

 wave, as a function of charge weight. 



