Subglacial Character of the Aurora Basin, East Antarctica, from Novel Seismic Waveform Modelling

Abstract:

The Aurora Basin in Wilkes Land, East Antarctica, is a critical sector in estimations of future sea level contributions from the continental ice sheet. The region is mostly grounded below sea-level and drains through the most rapidly thinning glacier in East Antarctica, the Totten Glacier, with evidence for potential deep sub-shelf intrusions of modified Circumpolar Deep Water and future retreat highly sensitive to the bedrock topography close to the present grounding line. Whilst remote sensing techniques have extensively chartered the region, the nature of the subglacial ice – bedrock interface, which acts as a key control on ice sheet dynamics and evolution, remains poorly understood. Seismological techniques have proven their capability to interpret sub-surface structures underneath the ice sheet, and passive methods utilising teleseismic signals and ambient noise afford the possibility for remote site coverage at a sufficient spatial resolution without the requirement of active sources.

This research aims to map comprehensively the basal environment of key areas within the Aurora Basin, with particular focus on the sedimentary distribution and thermal state at the ice – bedrock transition zone, in order to identify subglacial localities capable of promoting rapid ice sheet degradation and inform future seismic instrumentation deployment within the sector. We review the current state of geophysical knowledge regarding the Aurora Basin through the compilation and analysis of existing observational data, alongside the application of newly developed computational techniques in seismic waveform modelling to infer subglacial characteristics that could be indicative of future ice sheet collapse. Other factors influencing the basal system such as subglacial hydrology and coupled ice-ocean interactions will also be considered as we steadily improve our understanding of the ice sheet - bedrock interface across the region.