Open AccessInversion of field data in fault tectonics to obtain the regional stress—III. A new rapid direct inversion method by analytical means
Author(s) -
Angelier Jacques
Publication year - 1990
Publication title -
geophysical journal international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0956-540X
DOI - 10.1111/j.1365-246x.1990.tb01777.x
Subject(s) - geology , slip (aerodynamics) , shear (geology) , stress field , cauchy stress tensor , shear stress , inversion (geology) , slip line field , seismology , principal stress , tectonics , inverse problem , inverse theory , geometry , geodesy , mathematical analysis , mechanics , mathematics , physics , structural engineering , deformation (meteorology) , engineering , petrology , oceanography , finite element method , thermodynamics
SUMMARY A new method for determining the reduced stress tensor with four degrees of freedom (the orientations of the three principal stress axes as well as the ratio of principal stress differences) using fault slip data (or focal mechanisms of earthquakes) is presented. From a computational point of view, the inversion of fault slip data is made in a direct way by purely analytical means; as a result, the determination process is extremely fast and adaptable on small microcomputers. From a physical point of view, the method aims at simultaneously (i) minimizing the angles between theoretical shear stress and actual slip vector and (ii) having relative magnitudes of shear stress large enough to induce slip despite rock cohesion and friction. Examples of application to actual fault slip data sets with good or poor variety of fault slip orientations are shown. The double significance of the basic criterion adopted results in a more realistic solution of the inverse problem than the single minimization of the shear‐stria angle.