Development of inversion methods on fault slip data: Stress state in orogenes of the Central Asia

Abstract

Algorithm of natural stress reconstruction based on data on slip fault sets is presented. Also additional physical principles following from generalization of experimental geomechanics and theoretical tectonophysics are considered. It gives possibility to define not only orientation of stress tensor principal axis but also the ratio of its spherical and deviatory components. The characteristic feature of the method is that it simultaneously calculates mutually consistent components of stress tensor and increment tensor of seismotectonic deformations, what was missing in previously known methods of tectonophysics. The application of the method is illustrated by two case studies in seismoactive zones of Central Asia: a) Altai and Sayan and b) Northern Tien Shan. Results of stress reconstruction in this intra-plate faulted and folded domains demonstrate that the impact of crust flow and mantle heterogeneity on stresses is great. These processes can contribute much more in generating stresses in crust than interaction of lithosphere plates at distant borders.