1416 BURTON McCOLLUM AND WILTON W. LaRUE 

SURFACES@DETECTOR 
_ NEARBWELL 


ETECTOR— 3 : 
6690 

SHOOTING DISTANCE 
29480 FT. 

Fic. 6.—Typical record made with special seismic wave detector in well at depth 
of 6,690 feet (left trace). Notice greater velocity as compared with detector on sur-. 
face near well (right trace). Shooting distance was 29,490 feet. Middle trace was 
not used. 
126 
