Determination and interpretation of glacial-isostatic deformations of the Earth's crust in West Greenland

• Applicants: Professor Dr.-Ing. Martin Horwath; Dr.-Ing. Mirko Scheinert
• Subject Area: Geodesy, Photogrammetry, Remote Sensing, Geoinformatics, Cartography
• Term: from 2018 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 390339083

Past and present changes of ice masses and their interaction with Earth rheology and global oceanic mass redistribution induce complex patterns of load deformations of the Earth crust. In the southern part of West Greenland, the glaciation history is particularly complex, including a glacial re-advance in the late Holocene. Current knowledge of this glaciation history is particularly uncertain, which is partly due to insufficient coverage by measurements of present-day crustal deformation.The present project will determine deformations of the Earth crust in West Greenland by precise geodetic GNSS measurements.Field campaigns will be carried out to re-observe the 14 sites of a GPS network which was established in 1995 and was first re-observed in 2002. Additional 11 sites which have been added to the network between 2004 and 2010 will be re-observed --- mostly for the first time. Moreover, two continuous GNSS sites will be added to the existing network of campaign sites.Beyond a quantitative extension of previous measurements, the new observations will allow for a new quality of scientific exploitation. In this way, a consistent, data-based description of crustal deformations in this sector of the ice sheet margin will become possible.The new GNSS observation data will be processed together with the data gathered since 1995 by the group of the applicants and with data from the complementary GNET (Greenland GPS Network) project and from the IGS (International GNSS Service). The Bernese GNSS Software will be used, with special attention on the application of a long-term consistent reference system.The analysis of the resulting coordinate changes will consider both the vertical component and the horizontal components. Special focus will be put on the gradients of deformation along East-West profiles. For the interpretation of the observed crustal deformations, the elastic response to ongoing ice mass changes and the (temporally linear) visco-elastic reaction to past load changes (glacial isostatic adjustment, GIA) will be considered separately. The elastic load deformation will be modelled based on present-day ice mass changes derived from satellite observations such as satellite altimetry and satellite gravimetry.After subtraction of the elastic component, estimates of GIA-induced crustal deformations will be obtained. They will be used to validate GIA models (and hence models of glaciation history) and will be incorporated in further studies with interdisciplinary partners.

• DFG Programme: Research Grants