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Detailed Bed Information at the Grounding Line of Rutford Ice Stream in West Antarctica Gleaned from Comprehensive Microseismic Event Relations, and Other Sources
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  • Ian R.J. Lee,
  • Sridhar Anandakrishnan,
  • Richard Alley,
  • Alex Brisbourne,
  • Andrew Smith
Ian R.J. Lee
Pennsylvania State University

Corresponding Author:[email protected]

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Sridhar Anandakrishnan
Pennsylvania State University
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Richard Alley
Pennsylvania State University
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Alex Brisbourne
British Antarctic Survey
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Andrew Smith
British Antarctic Survey
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Abstract

The nucleation and triggering of basal microseisms, or icequakes, at the bottom of glaciers as the ice flows over it can grant us valuable insights about deformation processes that occur at the bed. The collaborative efforts of Penn State University and the British Antarctic Survey (BAS) during the 2018/2019 austral summer enabled the deployment of several seismic arrays over 3 months in the Rutford Ice Stream in West Antarctica for monitoring natural source seismicity. Using the earthquake detection and location software QuakeMigrate, we generated unique high-resolution icequake catalogs, particularly at Rutford’s grounding line. Our data showed an unprecedented number of detected events which we used to resolve key topographical features and characteristics at the bed like sticky spots, and how they related to the continuous ice loading-slipping process at the bed. To properly quantify relations between events, we performed rigorous testing via manual event inspection at each array to determine a trigger threshold that aims to balance event coverage with artefact minimization. To handle the massive amounts of incoming seismic data and subsequent located icequakes, we also created a systematic data processing pipeline, and used machine learning clustering algorithms to resolve inter- & intra-clusters spatial and temporal relations. We present our pre-processing methods on handling similarly large datasets and present findings from our seismic data in combination with other data sources, like GPR and tidal gauge data, that improves our understanding of ice flow dynamics in the region.