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B. V. KOTLIAREVSKII 



1. The gravimetric survey of the Shar'iusk party No. 23/53 in the north- 

 eastern part of the Moscow synchnal basin in 1953 (R. F. Volodarskii). 



The aim of the work was to study regional tectonics. The area of the 

 survey was 7200 km^, the number of the coordinate points was 674. The 

 points were distributed sufficiently evenly within the limits of the area of 

 work. From the value of the area S and the number of points N, using the 

 formula 



Vs 



a = 1.138 



]/N-l 



(32) 



which we give without derivation*, we will determine the mean distance 

 between the observation points. It is equal to 3.9 km. The mean square 

 error in the observation a = ± 0.62 mgal. 



The map with a cross -section of isoanomalies every 2 mgal was drawn 

 to a scale of 1:200,000. Furthermore, in the calculation use was made of 

 a compound map of the area of work by the 20/53, 21/53, and 23/53 parties 

 with the same cross-section of isoanomalies to a scale of 1:500,000. Using 

 this map, which covered a much larger area than the calculation map, we 

 find the average amplitude and the linear dimensions of the anomaly: 

 gQ — 9.5 mgal and Iq = 15.5 km. All further calculations will be made 

 on the assumption that the error in calculation of ±0.62 mgal characterizes the 

 error in the value of gravity at a consecutive point, since for the survey 

 under consideration the remaining errors are small. 



The results of the calculations are given in Table 4, which also gives 

 calculations for a less dense network of observations: in the second line 

 for o, it is doubled, and in the third line, it is trebled in comparison with 

 its actual value. 



With increase in a the value Eq^^^ remains constant, as it should do. The 

 values of E^^ and E^^ increase with increase in a. The value Dq^ with increase 



Table 4. Accuracy of Gravimetric survey Shar'insk party No. 23/53 



* The formula is derived with the assumption that the points are distributed over a square 

 network. When the points are not on a square network, this formula gives results with an 

 error not greater than 5-6%. 



