NW Australian intraplate seismicity and stress regime

摘要

The interrelations between stress orientation, regional deformation, and seismic activity in the context of intraplate seismicity continue to pose difficult questions. Stress models of the Australian continent are largely based on nonseismic information. Our study of 26 microearthquakes in NW Australia shows that they are good indicators of the seismogenic stress field. By inverting focal mechanisms calculated from the events we obtained deviatoric stress tensors in full agreement with the known in-situ stress field. The stress tensors corroborate the elastic modeling of the continent. The methods used here have widespread applicability in determining crustal stress field parameters in regions where in-situ stress data are sparse or absent.