GURN - GNSS Upper Rhine Graben Network


In April 2008 the Institut de Physique du Globe de Strasbourg (Ecole et Observatoire des Sciences de la Terre) and the Geodetic Institute of the University Karlsruhe (TH) established an international cooperation called GURN (GNSS Upper Rhine Graben Network). Within the GURN initiative these institutions are cooperating in order to carry out research in the framework of the transnational project TOPO-WECEP (West and Central European Platform), which succeeds the former project EUCOR-URGENT (Upper Rhine Graben Evolution and NeoTectonics). The proposed research is based on GNSS (Global Navigation Satellite Systems) in order to detect recent crustal movements.


Geoscientific Context

The Rhine Graben is the central, most prominent segment of the European Cenozoic rift system (ECRIS, fig. 1) of Oligocene age which extends from the North Sea through Germany and France to the Mediterranean coast over a distance of some 1000 km. Within GURN the focus will be on the Upper Rhine Graben (URG). The URG is a 300 km long and 40 km wide SSW-NNE trending rift, extending from Basel (Switzerland) to Frankfurt (Germany), see fig. 2. It is bounded to the west by the Vosges mountains and to the east by the Black Forest. The graben is bounded to the north by the uplifted area of the Rhenish Massif. To the south, the Leymen, Ferrette and Vendlincourt folds represent the northern-most structural front of the Jura fold and thrust belt. This thin-skinned compressive deformation front would propagate 30 km further to the north up to Mulhouse (France).

Preceded by late Cretaceous volcanism, the rifting was initiated during Late Eocene to early Miocene (42-31 Ma) starting with broadly east-west or ENE-WSW extension and lasted until Aquitanian time (fig. 3). Today, the southern end of the Rhine Graben is characterized by small uplift and subsidence rates (Mälzer 1986) and by a quasi-compressive, left-lateral strike-slip tectonic regime (fig. 3), with a maximum stress-axis oriented NW-SE (fig. 4).

The URG is considered to be the most seismically active region of northwest Europe with significant probability for the occurrence of large earthquakes. For a better understanding of the processes that lead to seismic activity in the URG, it is necessary to study not only the location of the faults but also their kinematics. Seismic hazard assessment in the region are hindered by a lack of information on the movements of the active structures.


Fig.1: The European Cenozoic Rift System (ECRIS) in Europe. The red square indicates the GURN region. Image modified from Ziegler (1992).

Fig.2: Seismotectonic framework of the Lower and Upper Rhine Graben. Squares depict the instrumental seismicity from 1910 to 1990 (1<M<5.5). Circles correspond to the historical seismicity (Meghraoui et al. 2001).

Fig.3: Time scale for the development of the Upper Rhine Graben rift system. A- Kinematics of faults for the different phases of development of the graben (Schumacher 2002). B- Stress conditions for the different phases as described by Schumacher (2002). C- Development of the stress field as described by Michon et al. (2003). Figure from Lopes-Cardozo (2004).

Fig.4: Map of the directions of maximum horizontal compression in the western Alpine foreland. Figure from Lopes-Cardozo (2004), obtained from the website of the World Stress Map project maintained at the University Karlsruhe (TH) (Link).

The GNSS sites of GURN

gurn_gnss1     gurn_gnss2      GURN actually includes German and French continuous GPS sites.
French sites have several origins: RENAG (Universities and research institutes), RGP (network of IGN), Teria, Orpheon. EOST sites are underlined by a black dot.
Most data of the German sites are provided from SAPOS®-Baden-Württemberg.
In the future it is planed to include other SAPOS® sites (SAPOS®-Rheinland-Pfalz) and data from Switzerland (Swisstopo, ETH Zürich).

The goals of GURN

The primary goal of the GURN project as a long term project is to obtain precise estimates of horizontal and vertical movements of the area under research.

In the beginning of this project all available data of permanently observing GNSS sites have to be checked, in order to evaluate the data quality and to be able to select suitable sites and data processing strategies.

The GNSS-related research aims within GURN are:

  • short term: Automated web-based presentation of results in near real-time
  • short term: Generation of highly precise daily GURN solutions, starting 1st Jan. 2008.
  • short term: Carrying out investigations in order to achieve an improved stochastic GNSS modeling, (keywords: site specific error handling, correlations, SNR-based weighting)
  • long term: Automated generation of extended water vapor fields
  • long term Revised geodynamic model of the URG area


Recent Results

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GURN integrates the GPS data provided by a lot of public institutions and private companies. We thank all the people and organisations who contribute to the acquisition of the data in Germany and in France and allow their use for scientific purposes.





Knöpfler, A. / Mayer, M.
Zur Detektion von Krustenbewegungen basierend auf GNSS-Daten von SAPOS-Permanentstationen.
Presentation, Herbsttagung 2007, Arbeitskreis Geodäsie/Geophysik, 16.-19. Okt. 2007, Freudenstadt, Germany.

Knöpfler, A. / Mayer, M. / Heck, B.
Monitoring of SAPOS® sites using tiltmeters.
Presentation, DAAD-program ProBrAl, 15. Aug. 2008, Curitiba, Brasil.

Masson, F. / Mayer, M. / Ferhat, G. / Knöpfler, A. / Heck, B. / Ulrich, P.
GURN (GNSS Upper Rhine Graben Network): Research Goals and First Results.
Poster, 14th General Assembly of WEGENER - WEGENER 2008, 15.-18. Sept. 2008, Darmstadt, Germany.

Knöpfler, A.
Zum Potenzial von GNSS Permanentstationen am Beispiel GURN.
Mitarbeiterseminar, Geodätisches Institut, Universität Karlsruhe (TH), 18. Dez. 2008.


Dr.-Ing. Michael Mayer (Chair of the GNSS working group)
Geodetic Institute, Karlsruhe Institute of Technology (KIT)
Englerstraße 7, D-76131 Karlsruhe, Germany
Tel.: ++49 (0)721 608 42724
Fax: ++49 (0)721 608 46808