EVALUATING THE ACCURACY OF A GRAVIMETRIC SURVEY 



159 



Table 2. Mean square error of the increase in the force of gravity 



BETWEEN neighbouring ISOANOMALIES (sECTION OF THE ISOANOMALIES 2 mgal) 



mean square values zIjq were determined. The results obtained in com- 

 parison with the theoretical values of A^q, found from formula (19), are 

 given in Table 3. 



The example considered is extremely unfavourable, since the "observed" 

 field was obtained with a very sparse network and the adopted mean 

 square observational error very large. 



Table .3. The mean square values of the first differences in Aiq for 

 various distances betv\'een the observation points 



Despite this, as shown by the data of the sixth columns of Tables 1 and 2 

 and the fifth column of Table 3, the results of checking the theoretical relation - 

 ships were very good. For a field with a denser network of observations and 

 with a smaller value of the mean square error in the force of gravity for 

 consecutive points, the comparison between theory and practice should 

 give results which, given a sufficient number of tests, will agree still more 

 closely. 



On the whole, the experimental check showed that the proposed method 

 for determining the errors in the gravity field, from the point of view of 

 the obtained accuracy, is suitable for use in practice. 



SOME EXAMPLES 



We give several examples of the use of the derived relationships for 

 determining the accuracy of gravimetric surveys made by production 

 concerns. 



