Vertical Crustal Movements in the Upper Rhine Graben Derived from Precise Levelling Data, SAR Interferometry and GNSS

• Applicant: Professor Dr.-Ing. Bernhard Heck
• Subject Area: Geodesy, Photogrammetry, Remote Sensing, Geoinformatics, Cartography
• Term: from 2009 to 2015
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 79132441

The goal of our project is the development of a methodology to derive large-scale, three-dimensional velocity fields in the Upper Rhine Graben (URG) area using a combination of levelling, Persistent Scatterer SAR interferometry (PSI) and GNSS. In the first part of this project, granted by German Research Foundation (DFG), the basis for the vertical displacement component has been set by consistent least squares adjustment of transnational levelling data from Germany, France and Switzerland. In the hereby applied second part of the research project, displacement rates derived from PSI and from time series of continuously operating GNSS sites in the URG shall be added to the levelling data in order to spatially densify the existing information on the vertical displacements as well as to quantify horizontal displacements. To this end, SAR scenes of the C-band satellites ERS1/2 and ENVISAT shall be analysed in a 250 km long and 100 km wide stripe between Basel and Mannheim by applying the PSI method. With respect to the detection of long-wave displacement phenomena using the C-band data archive, the focus is on the implementation and testing of a new procedure for the separation of orbit errors in the PSI processing chain. Concerning the GNSS analysis the project can benefit from comprehensive preliminary work, carried out at Geodetic Institute, Karlsruhe Institute of Technology, and directly use the results for horizontal and vertical displacement rates at the sites of the GNSS Upper Rhine Graben network (GURN). The main focus of the second part of the project is on a combination of the three geodetic measurement techniques for the detection of surface displacements (levelling, PSI, GNSS) in order to derive a consistent, three-dimensional velocity field for the whole URG at a high spatial resolution. The approach shall exploit the individual advantages of the measurement techniques (accuracy, spatial and temporal resolution) in an optimum way. As the data and the results of the three techniques are (i) inhomogeneous in space and time, and (ii) related to different reference levels, appropriate interpolation methods have to be developed and applied on the present combination problem. Because of the presumably large inhomogeneity in the distribution of the measurement points, approaches for a line-wise interpolation of the data shall be investigated in addition to the spatial interpolation using the Kriging method. Besides the detection and modelling of the surface displacements another focus of the research project is on the separation of anthropogenic, environmental (non-tectonic) and tectonic deformation. Areas with local displacement anomalies due to anthropogenic exploitation of the subsurface have to be omitted as far as possible for large-scale studies, but may be useful for detailed investigations and sensitivity analyses.

• DFG Programme: Research Grants
• Participating Person: Dr. Malte Westerhaus