Determination of tectonic stress field from fault slip data: toward a probabilistic model

Abstract

A model based on probability theory is proposed to determine the orientation of the tectonic stress field from fault slip and earthquake focal mechanism data. On the assumptions that 1) slip and shear stress direction on the fault plane coincide, and 2) measured slip direction and fault plane orientation are random variables following the von Mises and the Fisher distribution, respectively, the effects of measurement errors in both variables on stress field inversion are considered. A new inversion method is proposed that takes both measurement errors simultaneously into account. This method makes it possible to evaluate statistically the extent and significance of the deviations of the stress field from uniformity, i.e., the likelihood that a given fault population originates from a constant tectonic stress state. -from Authors