Geophysical Data to Inform Ice-Bedrock Interface Zone and Glacier Processes

This parent data holding includes geophysical data, including seismic, magnetotelluric and glacier geophysics information. The field data acquisition makes use of GRIT Facility (Geophysical Research Instruments for AnTarctica), which was established using funding including ARC LIEF (2020) and AuScope NCRIS (2022, 2023) with a focus on ice sheet monitoring for the Antarctic Continent using geophysical instruments, with close alignment to Australian Antarctic Program priorities in Climate, Sea Level Change and Monitoring Antarctica. The GRIT Facility includes both seismic and magnetotelluric instruments. Seismic methods enable the detection of icequakes and the inference of material properties, while magnetotelluric methods enable the detection of saline subglacial water (i.e. subglacial water with possible ocean influences).Predictions of ice sheet behaviour are limited by lack of detailed information on the ice sheet-bedrock interface zone, and by detailed knowledge of glacier processes for a given location. This data holding provides raw data records of naturally occurring background, local and teleseismic seismic signals, recorded by rapidly deployed posthole instruments. It also includes data records of naturally occurring magnetotelluric signals. These signals types may be used either individually, or using computational approaches that combine geophysical signal types. Seismic recordings are made where possible through a seasonal cycle to understand any impact of the time of year on the patterns of icequakes, recorded background noise, and any seasonal changes to the ice sheet bedrock interface zone. The hidden zone at the base of ice sheets includes features such as sediment layers, that may be saturated or not, be frozen or not, and lie over bedrock of variable composition. This ice-bedrock interface zone can also include sub-ice meltwater channels or subglacial groundwater. All these features help to control the past and present behaviour of the Antarctic ice sheets and how easily they slide over the rock beneath. Icequakes enable us to detect and monitor changes in how glaciers and ice sheets are evolving. We can make better decisions on the future impact of sea level rise if we understand ice sheet foundations, structures, processes and change, and whether any predicted changes will occur gradually or suddenly.