THE LOOP METHOD IN EXPLORING BURIED STRUCTURES 



259 



This is confirmed by the results of a reconnaissance profile, carried out by 

 the loop method. Within the limits of the gravitation anomaly, the profile 

 indicated the folding of the strata, which is of practical interest in correlating 

 the surface and the deep structure. The intersecting of the gravitation anomaly, 

 by a number of reconnaissance profiles at distances of 1-2 km from one 

 another would probably facihtate surveys of the second order folding on 

 the background of the large structure of the Ust-Urt. An example of a similar 

 detailed study is the section covered by the loop method in the southern 

 part of the gravitation anomaly (Fig. 9). 



In 1953 the NIIGR electrical prospecting laboratory carried out experi- 

 mental work to test the possibility of increasing the depth of investiga- 

 tion by the loop method and to increase its efficiency. 



To solve the first problem observations were made of the final stage 

 of stabihzation of an electromagnetic field in the earth, which characterizes the 







\/ 



I y 



;/ 



/\ 



/;» 



i 



[23 1 EI]2 i,n-3 



lOO I 2 5 4 500 



Fig. 9. The arrangement of loop profiles on the Il'todzhe section (Ust'-Urt). 1 — loop 

 vectors; 2 — lines normal to the loop vectors; 3 — number of profiles. 



17* 



