FIGURE 2-8. TYPICAL METHOD OF CONTINUOUS SEISMIC PROFILING, NORMAL INCIDENCE RE- 

 FLECTION ABOVE AND OBLIQUE REFLECTION BELOW, USED TO MEASURE SUB- 

 BOTTOM STRUCTURE. (ADAPTED FROM M. N. HILL, ED., THE SEA, VOL. 3, INTER- 

 SCIENCE, NEW YORK, 1963.) 



SHIP 

 UNDERWAY 



SUFFICIENT DISTANCE TO APPROX. 



MINIMIZE SHIP'S NOISE 10 ft 



(« 800 ft) 



SPARK AND RECEIVER 

 TOWED ASTERN 



WATER BOTTOM 



\\^s U B- bottomXN" 



REFLECTING HORIZONS 



Ifii 



SPARK 

 3 TO 5 ft — 

 BELOW WATER SURFACE 



HYDROPHONE 



PREFERABLY 

 SHIP LYING TO 



HYDROPHONE MOVED AWAY FROM 



OR TOWARD SPARK SOURCE 



— > 



FLOAT 



^hydrophone\ 



//'/yZ/y^Z'. 



30 



