DGFI-TUM is responsible for the realization of the International Terrestrial Reference System (ITRS) as one of three combination centers of the International Earth Rotation and Reference System Service (IERS) worldwide - besides JPL/NASA (USA) and IGN (France). The ITRS is the global coordinate system of highest accuracy and the basis for worldwide positioning and navigation, e.g. when using GPS. The ITRS is realized by combining the observation data of geodetic observatories distributed worldwide, with the Geodetic Observatory Wettzell operated by TUM being one of the most important stations. Some of the observatories are located in seismically active areas, and their positions show significant nonlinear changes in the aftermath of earthquakes.
The DGFI-TUM project aims at improving methods for the analysis and approximation of these postseismic deformations. Geophysical conditions at specific GNSS (Global Navigation Satellite Systems) observation sites will be investigated. Numerical modeling of the response of the upper part of the ground to seismic events will be used to study the nature of nonlinear deformation. The results of the modeling and the analysis of the records of seismic events will make it possible to find out how earthquakes affect the stations, depending on the ground beneath them. Improved modeling of postseismic deformations will result in significantly increased accuracies of ITRS station coordinates and station motions.