Observations of Buried Lake Drainage on the Antarctic Ice Sheet.

• Main Authors: Dunmire, D, Lenaerts, JTM, Banwell, AF, Wever, N, Shragge, J, Lhermitte, S, Drews, R, Pattyn, F, Hansen, JSS, Willis, IC, Miller, J, Keenan, E
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Geophysical Union (AGU) 2020
• Subjects: Antartica; GPR; glaciology; hydrofracture; hydrology; meltwater; Antarctic; The Antarctic; Buttress; Antarc*; Antarctica; antartic*; Ice Sheet; Ice Shelf; Ice Shelves
• Online Access: https://www.repository.cam.ac.uk/handle/1810/314848; https://doi.org/10.17863/CAM.61954

Between 1992 and 2017, the Antarctic Ice Sheet (AIS) lost ice equivalent to 7.6 ± 3.9 mm of sea level rise. AIS mass loss is mitigated by ice shelves that provide a buttress by regulating ice flow from tributary glaciers. However, ice-shelf stability is threatened by meltwater ponding, which may initiate, or reactivate preexisting, fractures, currently poorly understood processes. Here, through ground penetrating radar (GPR) analysis over a buried lake in the grounding zone of an East Antarctic ice shelf, we present the first field observations of a lake drainage event in Antarctica via vertical fractures. Concurrent with the lake drainage event, we observe a decrease in surface elevation and an increase in Sentinel-1 backscatter. Finally, we suggest that fractures that are initiated or reactivated by lake drainage events in a grounding zone will propagate with ice flow onto the ice shelf itself, where they may have implications for its stability.