Institute of Geodesy Research Research Projects
Gravimetry at Zugspitze and Wank Mountains (Bavarian Alps, Germany)

Gravimetry at Zugspitze and Wank Mountains (Bavarian Alps, Germany)

Left: A relative gravimeter in the vicinity of the Wank summit. Right: The geodynamic observatory of GFZ Potsdam with continuously operating GNSS antenna (bottom right, small green dot). On the first floor of the 3-storey building, the so-called "submarine", is the superconducting gravimeter, which mesures continuously, and the platform for absolute gravimetric observations performed episodically.
Led by:  Dr.-Ing. Ludger Timmen
E-Mail:  timmen@ife.uni-hannover.de
Year:  2018
Funding:  IFE, Germany’s Excellence Strategy – EXC-2123 “QuantumFrontiers”, GFZ Potsdam, TU München, Bayerische Akademie der Wissenschaften

The geodetic monitoring of variations caused by Alpine orogency and the diminishing permafrost are undertaken with gravimetric as well as geometric techniques. In addition to IfE (absolute and relative gravimetry, levelling), the Bavarian Academy of Sciences and Humanities (GNSS, levelling, relative gravimetry), the Institute of Astronomical and Physical Geodesy - Technical University of Munich (relative gravimetry) and the Helmholtz Centre Potsdam - GFZ German Research Centre for Geosciences (superconducting gravimetry, GNSS permanent geodynamic observatory on the Zugspitze) are involved in the cooperation.

Installed and first observed in 2004, two absolute gravimetric sites are located at the Wank Mountain, one at the foot of the mountain and one close to the summit (1780 m peak). At Zugspitze (2960 m), two sites are located very close to each other almost at the summit (established in 2004 and 2018) and one about 300 m below the summit in the Schneefernerhaus (environmental research station, since 2004). Outdoor points habe been installed based on relative gravimetry, densifying and expanding the whole network. This allows to tie the gravimetric net to geometrical points (GNSS, levelling).

The absolute gravimetric results from the Zugspitze show a clear gravity decrease since 2004 which can be only partly explained by an uplift of the Earth's crust (mountain building). The gravimetric and GNSS results for the Wank sites indicate stability of the Wank mountain area. Is the change at the Zugspitze summit caused by decreasing permafrost?