THEORETICAL STUDY ON ALEKSANDROWSKI′S METHOD OF THE GRAPHICAL DETERMINATION OF PRINCIPAL STRESS DIRECTIONS FROM THE FAULT SLIP DATA SETS

A graphical method for determining the principal stress distribution of a triaxial stress state from a fault slipstate was proposed by Aleksandrowski in 1985,based on Arthaud′s concept of plane movement,Alek-sandrowski′s method,however,is only valid for the cases in which the values of the stress ratios(C)are consid-ered 1o be ,10,2,1.1 and 1.Whether the method is applicable for general cases of all values of C has not yetbeen confirmed.In this paper.Aleksandrowskis′ method is tested using a numerical derivation from spatialgeometric analysis,and it is revealed that this method is correct for all values of stress ratios other than C=,10,2,1.1,and 1,i.c-<C<.