Solid-Earth Deformation in Patagonia: Geodetic Determination and Geodynamic Interpretation

• Applicant: Dr.-Ing. Mirko Scheinert
• Subject Area: Geodesy, Photogrammetry, Remote Sensing, Geoinformatics, Cartography
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 575188760

Patagonia, in southernmost South America, is generally characterized by a peculiar tectonic and rheological setting which causes an exceptional intensity of ongoing deformations of the solid Earth. In this proposal we focus on the area of the northern part of the Patagonian Slab Window, which includes the Northern Patagonian Ice Field (NPI). In this region, the principal geodynamic active processes are: a vigorous shallow mantle flow through the slab window, the glacial isostatic adjustment (GIA) to past and present ice-mass changes of the Patagonian ice fields, and plate subduction tectonics. Recent evidence for an unusually low mantle viscosity and an intense, probably accelerating, ice-mass loss make the NPI an ideal natural laboratory for exploring the transient deformation, which novel models predict as part of the viscoelastic response of the solid Earth to ice loads. The project aims to contribute to a better understanding of these processes by combining geodetic constraints and geophysical modelling. Endogenous and exogenous processes are expected to induce a deformation of the solid Earth with an intensity that is detectable in vertical and horizontal bedrock displacements derived from GNSS measurements. The spatial displacement pattern reflects the superposition of these processes, and an observational quantification of the recent deformation field is fundamental for a correct diagnosis of their individual contributions. However, the geodetic infrastructure is sparse in this region, and existing observational constraints on bedrock displacement are insufficient so far. The proposal exploits extensive previous work of the applicant in the broader region, building on geodetic observations around the Southern Patagonian Ice Field since 1996. In the immediate area under investigation, the group has already set up a network of GNSS measurement sites and initiated their observation. In the frame of the proposed project three GNSS measurement campaigns shall provide the geodetic observations necessary for the determination of bedrock displacements. A careful data analysis will be carried out, employing state of the art methods, tools and models, in order to derive accurate displacement rates and their temporal changes. Non-linear deformation signals can be expected under the particular conditions of the NPI and are instrumental to better understand transient GIA. The interpretation and synthesis of the new observational information will consist in the development, validation and parameter adjustment of geophysical models of the main geodynamic processes. This interpretation will include both the horizontal and vertical components of the bedrock displacement as well as non-linear temporal variations. The expected results are crucial for projecting relative sea-level changes and will contribute to the assessment of seismic hazards in a region of dynamic socio-economic development.

• DFG Programme: Research Grants