Role of Pre-existing Instability in Antarctic Ice Shelf Response to Distant Tsunamis Based on Remote Sensing

Antarctic ice shelves play a crucial role in regulating ice sheet mass balance, making their stability vital for understanding sea level rise. This study investigates the relationship between distant tsunamis and Antarctic ice shelf calving through multi-temporal remote sensing analysis. Three major calving events between 2011 and 2022 were examined: the East Sulzberger Ice Shelf calving following the 2011 Honshu earthquake tsunami, and the West Sulzberger Ice Shelf and Drygalski Ice Tongue calving events following the 2022 Hunga-Tonga volcanic tsunami. Long-term satellite observations of rift evolution and ice dynamics revealed that tsunami waves triggered calving only in ice shelves that had developed critical structural instabilities. This selective response was demonstrated by contrasting behaviors of neighboring ice shelves exposed to the same tsunami events, where ice shelves in stable states remained intact while those approaching critical conditions experienced calving. These findings emphasize the importance of pre-existing structural conditions in determining ice shelf response to external perturbations, highlighting the necessity of continuous satellite monitoring for identifying pre-calving conditions.