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dc.contributor.authorVore, Margot E.
dc.contributor.authorBartholomaus, Timothy, C.
dc.contributor.authorWinberry, J. Paul
dc.contributor.authorWalter, Jacob I.
dc.contributor.authorAmundson, Jason M.
dc.date.accessioned2020-03-27T16:07:11Z
dc.date.available2020-03-27T16:07:11Z
dc.date.issued2019-02-09
dc.identifier.citationVore, M. E., Bartholomaus, T. C., Winberry, J. P., Walter, J. I., & Amundson, J. M. (2019). Seismic tremor reveals spatial organization and temporal changes of subglacial water system. Journal of Geophysical Research: Earth Surface, 124, 427–446. https://doi.org/10.1029/2018JF004819en_US
dc.identifier.urihttp://hdl.handle.net/11122/10936
dc.description©2019. American Geophysical Union. All Rights Reserved.en_US
dc.description.abstractSubglacial 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, that 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.en_US
dc.description.sponsorshipRaw seismic data described in this paper are available through the Incorporated Research Institutions for Seismology Data Management Center (http://ds.iris.edu/mda/ZQ? timewindow=2015‐2016; Amundson et al., 2015). The raw weather data used in this paper can be found through the Arctic Data Center (https://doi.org/ 10.18739/A2H98ZC7V; Bartholomaus & Walter, 2018). Python code developed to carry out the analyses presented here is available at https://github.com/ voremargot/Seismic‐Tremor‐Reveals‐ Spatial‐Organization‐and‐Temporal‐ Changes‐of Subglacial‐Water‐System and https://github.com/ tbartholomaus/med_spec. This study was made possible with support from the University of Texas Institute for Geophysics and the University of Idaho. We thank Ginny Catania for the loan of weather stations. J. P. W.'s and J. M. A.'s contributions to this work were supported by the U.S. National Science Foundation (OPP‐1337548 and OPP‐ 1303895). T. C. B. thanks Dylan Mikesell for an early conversation, which inspired the analysis presented here.en_US
dc.language.isoen_USen_US
dc.publisherAmerican Geophysical Unionen_US
dc.sourceResearch Articleen_US
dc.subjectsubglacial environmenten_US
dc.subjectglacier dynamicsen_US
dc.subjectconduit evolutionen_US
dc.subjectglaciohydraulicen_US
dc.subjectsubglacialen_US
dc.subjectpolarization analysisen_US
dc.subjectTaku Glacieren_US
dc.subjectglacier dynamicsen_US
dc.subjectseismic tremoren_US
dc.subjectconduit flow pathen_US
dc.subjectsubglacial hydrologic systemen_US
dc.subjectsubglacial dischargeen_US
dc.subjectglacier bedsen_US
dc.subjectmelt‐water inputen_US
dc.subjecttremor frequenciesen_US
dc.subjectdelta‐like flowen_US
dc.subjectgradientsen_US
dc.subjectvertical ground motionen_US
dc.titleSeismic Tremor Reveals Spatial Organization and Temporal Changes of Subglacial Water Systemen_US
dc.typeArticleen_US
dc.description.peerreviewYesen_US
refterms.dateFOA2020-03-27T16:07:12Z
dc.identifier.journalJournal of Geophysical Research: Earth Surfaceen_US


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