Effect of Lateral and Stress‐Dependent Viscosity Variations on GIA Induced Uplift Rates in the Amundsen Sea Embayment
Abstract Accurate glacial isostatic adjustment (GIA) models are required for correcting measurements of mass change in Antarctica and for improving knowledge of the sub‐surface, especially in areas of large current ice loss such as the Amundsen Sea Embayment (ASE). Regionally, seismic and gravity da...
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ftdoajarticles:oai:doaj.org/article:2639531ba2cd4d579daadfb256fd94f4 2023-12-03T10:09:24+01:00 Effect of Lateral and Stress‐Dependent Viscosity Variations on GIA Induced Uplift Rates in the Amundsen Sea Embayment B. Blank V. Barletta H. Hu F. Pappa W. van der Wal 2021-09-01T00:00:00Z https://doi.org/10.1029/2021GC009807 https://doaj.org/article/2639531ba2cd4d579daadfb256fd94f4 EN eng Wiley https://doi.org/10.1029/2021GC009807 https://doaj.org/toc/1525-2027 1525-2027 doi:10.1029/2021GC009807 https://doaj.org/article/2639531ba2cd4d579daadfb256fd94f4 Geochemistry, Geophysics, Geosystems, Vol 22, Iss 9, Pp n/a-n/a (2021) GIA background stress finite element model (FEM) Amundsen composite rheology viscosity variations Geophysics. Cosmic physics QC801-809 Geology QE1-996.5 article 2021 ftdoajarticles https://doi.org/10.1029/2021GC009807 2023-11-05T01:35:59Z Abstract Accurate glacial isostatic adjustment (GIA) models are required for correcting measurements of mass change in Antarctica and for improving knowledge of the sub‐surface, especially in areas of large current ice loss such as the Amundsen Sea Embayment (ASE). Regionally, seismic and gravity data suggests lateral differences in viscosity (3D). Furthermore, mantle flow laws allow for a stress‐dependent effective viscosity which changes over time (3D‐s). In this study we investigate whether models with 3D/3D‐s have significant effects on the uplift in the region. We use a finite element model with composite rheology consisting of diffusion and dislocation creep, forced by an ice deglaciation model starting in 1900. We use its uplift predictions as synthetic observations to test the performance of 1D model inversion in the presence of viscosity variations. Stress‐dependent rheology results in lower viscosity beneath the load and a more localized uplift pattern. We demonstrate that the background stress from earlier ice load changes can both increase or decrease the influence of stress‐induced effective viscosity changes. For the ASE, fitting 1D models to 3D model uplift results in a best fitting model with viscosity that represents the average of a large area, while for 3D‐s rheology, local viscosity is more influential. 1D models are statistically indistinguishable from 3D/3D‐s viscosity with current GPS stations. However, 3D and 3D‐s models should be taken into account when accurate uplift and gravity rate patterns are needed, as uplift can differ up to 45% compared to 1D models in between existing GPS stations. Article in Journal/Newspaper Amundsen Sea Antarc* Antarctica Directory of Open Access Journals: DOAJ Articles Amundsen Sea Geochemistry, Geophysics, Geosystems 22 9 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
GIA background stress finite element model (FEM) Amundsen composite rheology viscosity variations Geophysics. Cosmic physics QC801-809 Geology QE1-996.5 |
spellingShingle |
GIA background stress finite element model (FEM) Amundsen composite rheology viscosity variations Geophysics. Cosmic physics QC801-809 Geology QE1-996.5 B. Blank V. Barletta H. Hu F. Pappa W. van der Wal Effect of Lateral and Stress‐Dependent Viscosity Variations on GIA Induced Uplift Rates in the Amundsen Sea Embayment |
topic_facet |
GIA background stress finite element model (FEM) Amundsen composite rheology viscosity variations Geophysics. Cosmic physics QC801-809 Geology QE1-996.5 |
description |
Abstract Accurate glacial isostatic adjustment (GIA) models are required for correcting measurements of mass change in Antarctica and for improving knowledge of the sub‐surface, especially in areas of large current ice loss such as the Amundsen Sea Embayment (ASE). Regionally, seismic and gravity data suggests lateral differences in viscosity (3D). Furthermore, mantle flow laws allow for a stress‐dependent effective viscosity which changes over time (3D‐s). In this study we investigate whether models with 3D/3D‐s have significant effects on the uplift in the region. We use a finite element model with composite rheology consisting of diffusion and dislocation creep, forced by an ice deglaciation model starting in 1900. We use its uplift predictions as synthetic observations to test the performance of 1D model inversion in the presence of viscosity variations. Stress‐dependent rheology results in lower viscosity beneath the load and a more localized uplift pattern. We demonstrate that the background stress from earlier ice load changes can both increase or decrease the influence of stress‐induced effective viscosity changes. For the ASE, fitting 1D models to 3D model uplift results in a best fitting model with viscosity that represents the average of a large area, while for 3D‐s rheology, local viscosity is more influential. 1D models are statistically indistinguishable from 3D/3D‐s viscosity with current GPS stations. However, 3D and 3D‐s models should be taken into account when accurate uplift and gravity rate patterns are needed, as uplift can differ up to 45% compared to 1D models in between existing GPS stations. |
format |
Article in Journal/Newspaper |
author |
B. Blank V. Barletta H. Hu F. Pappa W. van der Wal |
author_facet |
B. Blank V. Barletta H. Hu F. Pappa W. van der Wal |
author_sort |
B. Blank |
title |
Effect of Lateral and Stress‐Dependent Viscosity Variations on GIA Induced Uplift Rates in the Amundsen Sea Embayment |
title_short |
Effect of Lateral and Stress‐Dependent Viscosity Variations on GIA Induced Uplift Rates in the Amundsen Sea Embayment |
title_full |
Effect of Lateral and Stress‐Dependent Viscosity Variations on GIA Induced Uplift Rates in the Amundsen Sea Embayment |
title_fullStr |
Effect of Lateral and Stress‐Dependent Viscosity Variations on GIA Induced Uplift Rates in the Amundsen Sea Embayment |
title_full_unstemmed |
Effect of Lateral and Stress‐Dependent Viscosity Variations on GIA Induced Uplift Rates in the Amundsen Sea Embayment |
title_sort |
effect of lateral and stress‐dependent viscosity variations on gia induced uplift rates in the amundsen sea embayment |
publisher |
Wiley |
publishDate |
2021 |
url |
https://doi.org/10.1029/2021GC009807 https://doaj.org/article/2639531ba2cd4d579daadfb256fd94f4 |
geographic |
Amundsen Sea |
geographic_facet |
Amundsen Sea |
genre |
Amundsen Sea Antarc* Antarctica |
genre_facet |
Amundsen Sea Antarc* Antarctica |
op_source |
Geochemistry, Geophysics, Geosystems, Vol 22, Iss 9, Pp n/a-n/a (2021) |
op_relation |
https://doi.org/10.1029/2021GC009807 https://doaj.org/toc/1525-2027 1525-2027 doi:10.1029/2021GC009807 https://doaj.org/article/2639531ba2cd4d579daadfb256fd94f4 |
op_doi |
https://doi.org/10.1029/2021GC009807 |
container_title |
Geochemistry, Geophysics, Geosystems |
container_volume |
22 |
container_issue |
9 |
_version_ |
1784263489109360640 |