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

我们的项目的目标是开发一种方法来获得大规模的，三维速度场在上莱茵河地堑（URG）地区使用水准测量，持续散射SAR干涉测量（PSI）和GNSS的组合。在德国研究基金会（DFG）资助的该项目的第一部分中，通过对来自德国、法国和瑞士的跨国水准测量数据进行一致的最小二乘平差，确定了垂直位移分量的基础。在本研究项目的第二部分中，应将从PSI和从URG中连续运行的GNSS站点的时间序列中得出的位移率添加到水准测量数据中，以便在空间上增加关于垂直位移的现有信息，并量化水平位移。为此目的，将采用PSI方法，在巴塞尔和曼海姆之间的一个250公里长、100公里宽的条带内分析C波段卫星ERS 1/2和ENVISAT的合成孔径雷达景象。关于利用C波段数据档案探测长波位移现象，重点是实施和测试一个新程序，用于分离PSI处理链中的轨道误差。关于全球导航卫星系统的分析，该项目可受益于卡尔斯鲁厄理工学院大地测量研究所开展的全面的初步工作，并可直接使用全球导航卫星系统上莱茵河地堑网络各站点水平和垂直位移率的结果。该项目第二部分的主要重点是将三种大地测量技术（水准测量、PSI、全球导航卫星系统）结合起来，用于探测地表位移，以便以高空间分辨率得出整个URG一致的三维速度场。该方法应以最佳方式利用测量技术的个别优势（准确度、空间和时间分辨率）。由于这三种技术的数据和结果（i）在空间和时间上不均匀，以及（ii）涉及不同的参考水平，因此必须制定适当的插值方法，并将其应用于目前的组合问题。由于测量点的分布可能存在很大的不均匀性，除了使用克里格法进行空间插值外，还应研究数据的线性插值方法。除了地表位移的探测和建模之外，研究项目的另一个重点是人为、环境（非构造）和构造变形的分离。由于地下的人为开采而具有局部位移异常的区域在进行大规模研究时应尽可能忽略，但对于详细调查和敏感性分析可能有用。

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.