Shear‐Layer Thickness and Structure Evolves With Effective Stress in Subglacial Environments
Abstract Moving glaciers shear and deform the subglacial till beneath them, with deformation concentrated in a thin shear‐layer. This shear‐layer's properties are partially controlled by effective stress, which depends on ice thicknesses and subglacial hydrological networks. Understanding the r...
Saved in:
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Wiley
2025-03-01
|
| Series: | Geophysical Research Letters |
| Online Access: | https://doi.org/10.1029/2024GL114109 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1849314247569309696 |
|---|---|
| author | Ian Madden Dougal D. Hansen Lucas K. Zoet Jenny Suckale |
| author_facet | Ian Madden Dougal D. Hansen Lucas K. Zoet Jenny Suckale |
| author_sort | Ian Madden |
| collection | DOAJ |
| description | Abstract Moving glaciers shear and deform the subglacial till beneath them, with deformation concentrated in a thin shear‐layer. This shear‐layer's properties are partially controlled by effective stress, which depends on ice thicknesses and subglacial hydrological networks. Understanding the relationship between effective stress and shear‐layer thickness helps characterize basal resistance to ice motion and inform subglacial landform formation. While experiments agree increasing effective stresses beget decreasing shear‐layer thicknesses at high effective stresses, a trend is unclear at low effective stresses. Continuum models predict that increased effective stresses yield increasing shear‐layer thicknesses, inconsistent with experiments. Here, we identify how properties of a medium's persistent contact network lead to non‐monotonic shear‐layer thicknesses in effective stress through Discrete Element Method simulations. We find effective stress can alter both shear‐layer thickness and structure, and thereby depth‐averaged friction. We integrate these insights into an existing continuum model by modifying its yield parameters, resolving inconsistency between model and experiment. |
| format | Article |
| id | doaj-art-0787e88c46744b4f9fd3ea0754de7dbd |
| institution | Kabale University |
| issn | 0094-8276 1944-8007 |
| language | English |
| publishDate | 2025-03-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geophysical Research Letters |
| spelling | doaj-art-0787e88c46744b4f9fd3ea0754de7dbd2025-08-20T03:52:32ZengWileyGeophysical Research Letters0094-82761944-80072025-03-01526n/an/a10.1029/2024GL114109Shear‐Layer Thickness and Structure Evolves With Effective Stress in Subglacial EnvironmentsIan Madden0Dougal D. Hansen1Lucas K. Zoet2Jenny Suckale3Institute for Computational and Mathematical Engineering Stanford University Stanford CA USAUniversity of Wisconsin‐Madison Madison WI USAUniversity of Wisconsin‐Madison Madison WI USAInstitute for Computational and Mathematical Engineering Stanford University Stanford CA USAAbstract Moving glaciers shear and deform the subglacial till beneath them, with deformation concentrated in a thin shear‐layer. This shear‐layer's properties are partially controlled by effective stress, which depends on ice thicknesses and subglacial hydrological networks. Understanding the relationship between effective stress and shear‐layer thickness helps characterize basal resistance to ice motion and inform subglacial landform formation. While experiments agree increasing effective stresses beget decreasing shear‐layer thicknesses at high effective stresses, a trend is unclear at low effective stresses. Continuum models predict that increased effective stresses yield increasing shear‐layer thicknesses, inconsistent with experiments. Here, we identify how properties of a medium's persistent contact network lead to non‐monotonic shear‐layer thicknesses in effective stress through Discrete Element Method simulations. We find effective stress can alter both shear‐layer thickness and structure, and thereby depth‐averaged friction. We integrate these insights into an existing continuum model by modifying its yield parameters, resolving inconsistency between model and experiment.https://doi.org/10.1029/2024GL114109 |
| spellingShingle | Ian Madden Dougal D. Hansen Lucas K. Zoet Jenny Suckale Shear‐Layer Thickness and Structure Evolves With Effective Stress in Subglacial Environments Geophysical Research Letters |
| title | Shear‐Layer Thickness and Structure Evolves With Effective Stress in Subglacial Environments |
| title_full | Shear‐Layer Thickness and Structure Evolves With Effective Stress in Subglacial Environments |
| title_fullStr | Shear‐Layer Thickness and Structure Evolves With Effective Stress in Subglacial Environments |
| title_full_unstemmed | Shear‐Layer Thickness and Structure Evolves With Effective Stress in Subglacial Environments |
| title_short | Shear‐Layer Thickness and Structure Evolves With Effective Stress in Subglacial Environments |
| title_sort | shear layer thickness and structure evolves with effective stress in subglacial environments |
| url | https://doi.org/10.1029/2024GL114109 |
| work_keys_str_mv | AT ianmadden shearlayerthicknessandstructureevolveswitheffectivestressinsubglacialenvironments AT dougaldhansen shearlayerthicknessandstructureevolveswitheffectivestressinsubglacialenvironments AT lucaskzoet shearlayerthicknessandstructureevolveswitheffectivestressinsubglacialenvironments AT jennysuckale shearlayerthicknessandstructureevolveswitheffectivestressinsubglacialenvironments |