| Title | Geodetic measurements for geothermal site monitoring at Soultz-sous-Forêts and Rittershoffen deep geothermal sites |
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| Authors | Heimlich, C; Masson, F; Schmittbuhl, J; Ferhat, G |
| Year | 2016 |
| Conference | European Geothermal Congress |
| Keywords | Geothermal monitoring, GNSS, InSAR, Time series, Surface displacement, PSI |
| Abstract | We establish a long-term geodetic monitoring around the geothermal sites of Soultz-sous-Forêts and Rittershoffen in the North of Alsace, France. The monitoring strategy is based on two space geodesy methods: Global Navigation Satellite System (GNSS) and Synthetic Aperture Radar Interferometry (InSAR) methods. This study presents the processing strategy and the results of the geodetic monitoring. The accuracy of the GNSS processing strategy is validated by an experimental test of controlled vertical displacement. This study shows the ability of the geodetic strategy to detect surface displacement at centimeter to millimetre level, depending of the duration of the measurements and of the technique used. Geodetic methods are a suitable tool for acceptability of the geothermal site. 1) It helps to discriminate between the geothermal source of displacement and others sources of surface displacement. 2) The cGNSS has the ability to be an alarm tool in case of incidents and before significant damages occur. E.g. if the power plant of Landau (Germany) had a cGNSS monitoring in 2013, the incident at the power plant (Heimlich et al 2015, 2016) would have been seen before cracks apparition on the power plant. 3) At long time scale, the results can be an input for reservoir modelling and give information about possible fault reactivation, induced seismicity and slow deformations that are not visible by seismometer. |