| Title | Geodetic analysis of surface deformation at the power plant of Landau (Germany) related to the 2013-2014 event |
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| Authors | Heimlich, C; Masson, F; Schmittbuhl, J |
| Year | 2016 |
| Conference | European Geothermal Congress |
| Keywords | Geothermal monitoring, Geodesy, InSAR, Times series, Surface displacement |
| Abstract | The power plant of Landau is an EGS geothermal site with a doublet configuration. It is located in the South of the city of Landau (Germany). Using Synthetic Aperture Radar (SAR) images from TerraSAR-X satellite, we observe pluri-centimeter surface displacement in the area of the power plant during the production phase. Our results are based on the analysis SAR images processed by Persistent Scatterers (PS) method with StaMPS software (Hooper et al. 2007). We obtain time series and velocity map of the surface displacement over the city of Landau and compare the PS-InSAR results to levelling and GNSS measurements made by the city of Landau. The analysis of time series shows that an uplift centered on the power plant location started in mid-2013 and continued until the plant shutdown in March 2014. Then a pluri-centimeter subsidence occurs centered at the same location. The vertical displacement at the power plant location is at least 12 cm. In this study, we present the observation and analysis of the surface displacements during the entire 2013-2014 period. We re-process and complete the results published in Heimlich et al. (2015) and go further in the analysis. We model the surface deformation with the elastic Mogi model (Mogi 1958) and Okada (Okada 1985) usually used in volcanology. Our modelling gives indication about the depth and the variation of volume that causes the deformation. The result is consistent with an injection of geothermal water at around 450 m depth. This study highlights 1) the ability of geodetic methods to analyze the origin of surface displacements, 2) the utility of geodetic monitoring for control and alarm of damages due to human activities, thus of geothermal projects. Our results give also indications about the geological structures that are differentially affected by the deformation. |