THE USE OF UNIAXIAL RECORDINGS IN MOMENT TENSOR INVERSIONS FOR INDUCED SEISMIC SOURCES

Abstract

This study shows that the use of uniaxial recordings maintains the linear dependence of the low frequency displacements, with first polarities included, on the moment tensor components, and thus can be easily incorporated in the evaluation of failure mechanism using a moment tensor approach. Synthetic data analysis demonstrates that the errors in the orientation of the principal strain axes of the mechanism solution can be reliably evaluated using a linear error propagation approximation for up to 30% variance in the amplitude data. Case studies at the Kidd Mine indicate that the general characteristics of the mechanism solution are well retrieved, regardless of the type of data used, as relatively small disorientation angles of 15-20° are found between the solutions derived from rotated triaxial data and those from unrotated triaxial data used as uniaxial data, and of 25-30° between the solutions based on rotated triaxial data and those on independent uniaxial data.