Detailed Bed Information at the Grounding Line of Rutford Ice Stream in
West Antarctica Gleaned from Comprehensive Microseismic Event Relations,
and Other Sources
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.