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Glacial isostatic adjustment and postseismic deformation in Antarctica

van der Wal, Wouter; Barletta, Valentina; Nield, Grace; van Calcar, Caroline

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Authors

Wouter van der Wal

Valentina Barletta

Caroline van Calcar



Abstract

This chapter reviews glacial isostatic adjustment (GIA) and post-seismic deformation in Antarctica. It discusses numerical models and their inputs, and observations and inferences that have been made from them. Both processes are controlled by mantle viscosity but their forcings are different. Ongoing GIA induced by the loss of ice since the last glacial maximum (LGM) could have amounted to 5–15 m of global sea-level rise. However, mantle viscosity is so low in parts of West Antarctica (c. 1018 Pa s) that changes in ice thickness over the last centuries and decades have controlled the current uplift rates there. The uplift due to GIA has promoted ice-sheet stability since the LGM, and in West Antarctica GIA is a significant negative feedback on the current decline of the ice sheet. Post-seismic deformation following the 1998 earthquake near the Balleny Islands south of New Zealand has been detected in global navigation satellite system (GNSS) data and compared to model outputs. The best-fitting viscosity for this area is c. 1019 Pa s, similar to GIA-based estimates for the Antarctic Peninsula. Future work should focus on unifying descriptions of viscosity across geodynamic models, and integrating information from seismic, gravity, experimental and geological data.

Citation

van der Wal, W., Barletta, V., Nield, G., & van Calcar, C. (2023). Glacial isostatic adjustment and postseismic deformation in Antarctica. Memoirs, 56(1), https://doi.org/10.1144/m56-2022-13

Journal Article Type Article
Online Publication Date Nov 10, 2022
Publication Date 2023
Deposit Date Oct 31, 2022
Publicly Available Date Jul 17, 2023
Journal Geological Society, London, Memoirs
Print ISSN 0435-4052
Electronic ISSN 2041-4722
Publisher The Geological Society
Peer Reviewed Peer Reviewed
Volume 56
Issue 1
DOI https://doi.org/10.1144/m56-2022-13

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