Glacial isostatic adjustment and post-seismic deformation in Antarctica

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

*Corresponding author for this work

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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.
Original languageEnglish
Title of host publicationThe Geochemistry and Geophysics of the Antarctic Mantle
EditorsA. P. Martin, W. van der Wal
Volume56
Place of PublicationLondon
PublisherGeological Society
Publication date2023
Edition1
Pages315–341
DOIs
Publication statusPublished - 2023
SeriesGeological Society Memoir
ISSN2041-4722

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