Seismic Tremor Reveals Spatial Organization and Temporal Changes of Subglacial Water System
Subglacial water flow impacts glacier dynamics and shapes the subglacial environment. However, due to the challenges of observing glacier beds, the spatial organization of subglacial water systems and the time scales of conduit evolution and migration are largely unknown. To address these questions,...
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ftcwashingtonuni:oai:digitalcommons.cwu.edu:cotsfac-1088 2023-05-15T16:20:37+02:00 Seismic Tremor Reveals Spatial Organization and Temporal Changes of Subglacial Water System Vore, Margot E. Bartholomaus, Timothy C. Winberry, J. Paul Walter, Jacob I. Amundson, Jason M. 2019-02-09T08:00:00Z application/pdf https://digitalcommons.cwu.edu/cotsfac/88 https://digitalcommons.cwu.edu/cgi/viewcontent.cgi?article=1088&context=cotsfac unknown ScholarWorks@CWU https://digitalcommons.cwu.edu/cotsfac/88 https://digitalcommons.cwu.edu/cgi/viewcontent.cgi?article=1088&context=cotsfac ©2019. American Geophysical Union. All Rights Reserved. All Faculty Scholarship for the College of the Sciences subglacial water system seismology glaciohydaulic tremor glaciology Geology text 2019 ftcwashingtonuni 2022-10-20T20:28:46Z Subglacial water flow impacts glacier dynamics and shapes the subglacial environment. However, due to the challenges of observing glacier beds, the spatial organization of subglacial water systems and the time scales of conduit evolution and migration are largely unknown. To address these questions, we analyze 1.5‐ to 10‐Hz seismic tremor that we associate with subglacial water flow, hat is, glaciohydraulic tremor, at Taku Glacier, Alaska, throughout the 2016 melt season. We use frequency‐dependent polarization analysis to estimate glaciohydraulic tremor propagation direction (related to the subglacial conduit location) and a degree day melt model to monitor variations in melt‐water input. We suggest that conduit formation requires sustained water input and that multiconduit flow paths can be distinguished from single‐conduit flow paths. Theoretical analysis supports our seismic interpretations that subglacial discharge likely flows through a single‐conduit in regions of steep hydraulic potential gradients but may be distributed among multiple conduits in regions with shallower potential gradients. Seismic tremor in regions with multiple conduits evolves through abrupt jumps between stable configurations that last 3–7 days, while tremor produced by single‐conduit flow remains more stationary. We also find that polarized glaciohydraulic tremor wave types are potentially linked to the distance from source to station and that multiple peak frequencies propagate from a similar direction. Tremor appears undetectable at distances beyond 2–6 km from the source. This new understanding of the spatial organization and temporal development of subglacial conduits informs our understanding of dynamism within the subglacial hydrologic system. Text glacier Alaska Central Washington University: ScholarWorks Taku ENVELOPE(-133.854,-133.854,59.633,59.633) |
institution |
Open Polar |
collection |
Central Washington University: ScholarWorks |
op_collection_id |
ftcwashingtonuni |
language |
unknown |
topic |
subglacial water system seismology glaciohydaulic tremor glaciology Geology |
spellingShingle |
subglacial water system seismology glaciohydaulic tremor glaciology Geology Vore, Margot E. Bartholomaus, Timothy C. Winberry, J. Paul Walter, Jacob I. Amundson, Jason M. Seismic Tremor Reveals Spatial Organization and Temporal Changes of Subglacial Water System |
topic_facet |
subglacial water system seismology glaciohydaulic tremor glaciology Geology |
description |
Subglacial water flow impacts glacier dynamics and shapes the subglacial environment. However, due to the challenges of observing glacier beds, the spatial organization of subglacial water systems and the time scales of conduit evolution and migration are largely unknown. To address these questions, we analyze 1.5‐ to 10‐Hz seismic tremor that we associate with subglacial water flow, hat is, glaciohydraulic tremor, at Taku Glacier, Alaska, throughout the 2016 melt season. We use frequency‐dependent polarization analysis to estimate glaciohydraulic tremor propagation direction (related to the subglacial conduit location) and a degree day melt model to monitor variations in melt‐water input. We suggest that conduit formation requires sustained water input and that multiconduit flow paths can be distinguished from single‐conduit flow paths. Theoretical analysis supports our seismic interpretations that subglacial discharge likely flows through a single‐conduit in regions of steep hydraulic potential gradients but may be distributed among multiple conduits in regions with shallower potential gradients. Seismic tremor in regions with multiple conduits evolves through abrupt jumps between stable configurations that last 3–7 days, while tremor produced by single‐conduit flow remains more stationary. We also find that polarized glaciohydraulic tremor wave types are potentially linked to the distance from source to station and that multiple peak frequencies propagate from a similar direction. Tremor appears undetectable at distances beyond 2–6 km from the source. This new understanding of the spatial organization and temporal development of subglacial conduits informs our understanding of dynamism within the subglacial hydrologic system. |
format |
Text |
author |
Vore, Margot E. Bartholomaus, Timothy C. Winberry, J. Paul Walter, Jacob I. Amundson, Jason M. |
author_facet |
Vore, Margot E. Bartholomaus, Timothy C. Winberry, J. Paul Walter, Jacob I. Amundson, Jason M. |
author_sort |
Vore, Margot E. |
title |
Seismic Tremor Reveals Spatial Organization and Temporal Changes of Subglacial Water System |
title_short |
Seismic Tremor Reveals Spatial Organization and Temporal Changes of Subglacial Water System |
title_full |
Seismic Tremor Reveals Spatial Organization and Temporal Changes of Subglacial Water System |
title_fullStr |
Seismic Tremor Reveals Spatial Organization and Temporal Changes of Subglacial Water System |
title_full_unstemmed |
Seismic Tremor Reveals Spatial Organization and Temporal Changes of Subglacial Water System |
title_sort |
seismic tremor reveals spatial organization and temporal changes of subglacial water system |
publisher |
ScholarWorks@CWU |
publishDate |
2019 |
url |
https://digitalcommons.cwu.edu/cotsfac/88 https://digitalcommons.cwu.edu/cgi/viewcontent.cgi?article=1088&context=cotsfac |
long_lat |
ENVELOPE(-133.854,-133.854,59.633,59.633) |
geographic |
Taku |
geographic_facet |
Taku |
genre |
glacier Alaska |
genre_facet |
glacier Alaska |
op_source |
All Faculty Scholarship for the College of the Sciences |
op_relation |
https://digitalcommons.cwu.edu/cotsfac/88 https://digitalcommons.cwu.edu/cgi/viewcontent.cgi?article=1088&context=cotsfac |
op_rights |
©2019. American Geophysical Union. All Rights Reserved. |
_version_ |
1766008541404987392 |