The interrelations between stress orientation, regional deformation, and seismicactivity in the context of intraplate seismicity continue to pose difficult questions. Stressmodels of the Australian continent are largely based on nonseismic information. Our studyof 26 microearthquakes in NW Australia shows that they are good indicators of theseismogenic stress field. By inverting focal mechanisms calculated from the events weobtained deviatoric stress tensors in full agreement with the known in-situ stress field. Thestress tensors corroborate the elastic modeling of the continent. The methods used herehave widespread applicability in determining crustal stress field parameters in regionswhere in-situ stress data are sparse or absent.