Fig. 11

The Airport 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. The blue line indicates the main anomaly; the orange broken line refers to the side effect on the SW. See Additional file 4: Figure D.7.1 for location of stations, Additional file 1: Appendix A for gravity data and B for information on the drillings. b and c Model 4 for the Airport profile, made with seven prisms with a uniform density contrast of − 500 kg/m³. d and e Model 7 for the Airport profile, made with eight prisms with a density contrast of − 500 kg/m³ for the top five prisms and − 350 kg/m³ for the three bottom prisms. For all figures: 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. The black bars indicate our maximum uncertainty of ± 0.13 mGal. The light blue line highlights the main anomaly. The figures also show the 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 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 Additional file 4: Figure D.7.1 for locations). The black rectangles show the cross sections of the prisms used for modelling. Please refer to Additional file 4: Appendix D.7 for more information