| Abstract |
Hypocentre location is one of the most important characteristic of any seismic event since many other seismic parameters can be derived from it (e.g. magnitude, focal mechanism) and several interpretation will also be based on it (e.g. geothermal reservoir extension). Thus knowledge of its reliability or, similarly, quantification of the location uncertainty is of importance prior to further use of this information and result interpretation. The study presented here aims at modelling seismic event location uncertainties, in the case of the geothermal site of Soultz-sous-Forêts (Alsace, France). Many seismological analyses have already been done on this research site because the numerous hydraulic stimulations which were performed induced seismicity. We focus here on the seismicity induced during the deep stimulation of the GPK2 well, carried out in 2000. This stimulation was monitored by several seismic networks and the seismic data processing was done using different combinations of networks and different velocity models (Dyer 2001, Cuenot et al. 2008). Also, 4D tomography was conducted (Cuenot et al. 2008, Calò et al. 2011) as well as inversion of the stress-field changes over time and depth based on the event focal mechanisms (Schoenball et al. 2014). Therefore, our analysis is a first step to characterize the effect of seismic location uncertainties in further processing of this basic attribute. In the following, we investigate the effects induced by the use of the different seismic monitoring networks. We also compare results obtained by two different location methods. Finally, we start looking at the effect generated by velocity model changes. |