184 E. I. Terekhin 



Furthermore, for — = oo curves were calculated with — = 1/5, 1/3, and 1/2. 



Q2 

 The curves mth — = were not calculated for a three -layer section 



since this case is not of practical interest for geoelectrical sections with an 

 upper layer of high conductivity. All curves were calculated both for the 

 symmetrical AMNB apparatus and for the dipole axial apparatus. Thus, 

 the total volume of calculated material was 420 curves combined according 



to the variable parameter — into 68 graphs. 



All these graphs were published in 1956 by the All-Union Research 

 Institute for Geophysical Methods of Prospecting (VNII Geofizika), as a collec- 

 tion of theoretical curves for sea probing. 



According to the new notation of theoretical probing curves adopted 

 in the NIGGR in 1956, all curves corresponding to the bottom position of 

 the apparatus are given the letter M ("morskie" — sea), at the beginning 

 of the number, and the number of curves calculated for a radial (dipole 

 axial) apparatus have the letter P. The variable parameter for which 

 the graph is prepared is designated by the letter c ("Soprotivlenie" — the 

 resistance, of the upper layer under the vvater) or m ("moshchnost" — the 

 thickness, of this layer), and the relative values of the attached parameters 

 of the section are shown by numbers. Thus, the graph M— c — 1/5— c^ 

 means that it contains the theoretical curves of probing with the symmetrical 

 AMNB apparatus at the boundary of the first and second layers; the resistance 



Qi . . 



of the second stratum — being different for different curves (it is named 



for each curve), its thickness constituting 1/5 of the thickness of the upper 



'QiV 



layer, and finally, the resistance of the underlying medium being 



As is known C^^, the theoretical probe curves in a general form are calculated 

 from the formula 



_1_ 



= l + 2^g„Z„, (27) 



n=l 



where q^ is a function depending only on the ratios of the resistances and 

 the thicknesses of the various levels and the serial number n; 

 l^ is a function depending only on the size of the apparatus and 

 the serial number n. 



