292 



V. I. FOMINA 



divergence of the curves. The resuhs obtained by interpretation were 

 confirmed by drilhng. 



The method for analysing distortions in VEP curves which has been 

 examined can also be apphed to dipole quadrilateral probing (DQP)*, for 

 which the characteristic distortions from non -horizontal boundaries will 

 be more sharply reflected. 



We shall examine distortions in DQP curves brought about by passage 



<a) 37 5000 



■(b) 



(c) 10,000 



(d)= 



(e) - ^ 



yi ' 15,000 



<g).'r.-- 



.(hH„ 20,000 



(i) 



■(j> - 25,000 



Fig. 16. a — VEP points; b — ohm isolines of qj^; c — ohm isoUnes of qj^ compensated 

 for the influence of surface distortions; d — Hnes of maximum decrease in Qf^ from deep 

 non -horizontal boundaries ; e — Unes of maximum increases in Qi^ from deep non-horizon- 

 tal boundaries; / — lines of minima of q/^ from surface non -horizontal boundaries; 

 g — Unes of the maxima of Qf^ from surface non -horizontal boimdaries; h — position 

 of the dipole MN for maximum deviations of qi^ from (oj ^)^ — influences of 

 surface non -horizontal boundaries ; i — abscissa of the maximum decrease in Qj^ from 

 the influence of deep non-horizontal boundaries; j — abscissa of the maximum increase 

 in g;^ from the influence of deep non -horizontal boimdaries. 



Literally dipole equatorial Bonding or (DES) in Russian. [Editor's footnote]. 



