Resolution of Non-double-couple Mechanisms in Microseismic Monitoring - Simulation of HDR Experiment at Soultz, Alsace

Mechanism of microearthquakes observed in induced seismicity (related to mining, hydrofracture experiments in industry etc.) may contain - in addition to the traditional shear slip - also non-double-couple components in the moment tensor. Their resolution can however be difficult taking into account errors in location of the hypocenter and modeling the velocity structure - effects which themselves generate spurious non-double-couple components. We simulate a shear-tensile source (slip vector off the fault plane) in the configuration of the seismic monitoring in the Soultz geothermal facility and explore resolution of the tensile component when various types of hypocenter mislocation and/or mismodeling the velocity structure take place. Effects of deteriorating the quality of the focal sphere coverage by seismic stations as well as absence of S data are also investigated.