Fig. 10

The Kehrsatz profile. a Bouguer anomalies and regional trend of the gravity field along the profile. The blue dots represent the stations where gravity data was collected for this study. See Additional file 4: Figure D.6.1 for location of stations, Additional file 1: Appendix A for gravity data and B for information on the drillings. Three MPs at c. 300 m profile distance show a zig-zag-pattern in the gravity signals (denoted with a question mark), which might be caused by local effects that we cannot fully explain. The green line indicates the topography effect, the dark blue line the gravity signal of the side anomaly, the pale blue line denotes the signal of the main trough, and the orange dashed line on the NE margin denotes the effect of a further side anomaly. b Final model for the Kehrsatz profile (including the topographic signal), made with seven prisms with a density contrast of -500 kg/m³ for the top four prisms and − 350 kg/m³ for the three remaining prisms. The blue dots represent the observed residual anomaly (the dot size corresponds to the average uncertainty of ± 0.04 mGal), and the orange dots are the modelled residual anomaly values for model 6. The black bars indicate our maximum uncertainty of ± 0.13 mGal. c Elevation (SwissAlti3D 2 m DEM (© swisstopo)) along the profile (blue solid line). The red broken line illustrates the bedrock topography of the model by Reber and Schlunegger (2016). The blue dots mark the locations of the gravity stations, the red diamonds indicate drillings that reached the bedrock. The red and white stars (both are > 900 m to the SE of the profile) indicate locations of two deep drillings, projected onto the profile. The red one reached the bedrock, the white one ended in the Quaternary sediments (see Figure D.6.1 for locations). The black rectangles show the cross sections of the prisms used for modelling. Please refer to Additional file 4: Appendix D.6 for more information