The grounding zone of the Ekström Ice Shelf, East Antarctica – Geophysical characterization using GNSS, seismology and magnetotellurics

• Main Authors: Fromm, T., Ritter, O., Weckmann, U., Heidrich-Meisner, K., Scheinert, M., Fofonova, V.
• Format: Conference Object
• Language: English
• Published: 2023
• Subjects: East Antarctica; Ekström Ice Shelf; Antarc*; Antarctica; Ice Sheet; Ice Shelf; Ice Shelves
• Online Access: https://gfzpublic.gfz-potsdam.de/pubman/item/item_5016386

Antarctica’s ice shelves are a highly critical component for the interlinkage between ice sheet and ocean. Their shape and evolution play an important role for the strength of ice mass loss, e.g. by amplification or weakening of the buttressing effect. Ocean tides are the most important direct forces acting on the ice shelves, inducing vertical and horizontal motion and deformation. In our study we investigate the effect of ocean tides on the Ekström Ice Shelf. The northward flow of the ice is mainly modulated by the tidal constituents at the ter-diurnal and quarter-diurnal bands, whereas the dominant vertical tides have a diurnal and semi-diurnal periodicity and amplitudes up to ten times larger than the ter- and quarter-diurnal tides. The causes of the higher frequency tidal modulations are still poorly understood. The area of the largest effect of the higher frequency tides is assumed to be the grounding zone of the ice streams feeding the ice shelf. Here we present first results of geophysical experiments at the grounding zone of the Ekström Ice Shelf conducted in the field seasons 2021/2022 and 2022/2023. In 2021/2022 we setup GNSS and seismic stations to record vertical and horizontal motion of the ice as well as seismic events in order to gain insights into ice dynamics and ground properties. In season 2022/2023 GNSS and seismic station were dismantled, and the experiments were complemented by magnetotelluric measurements to image the sub-ice ocean-land transition and the crustal structure beneath the ice stream.