Long-term evolution of the Sulzberger Ice Shelf, West Antarctica: Insights from 74-year observations and 2022 Hunga-Tonga volcanic tsunami-induced calving

• Published in: Earth and Planetary Science Letters
• Main Authors: Zhao, Aiguo, Cheng, Yuan, Fraser, Alexander D., Bennetts, Luke G., Xiao, Haifeng, Liang, Qi, Li, T., Li, Rongxing
• Other Authors: Australian Research Council, Agencia Estatal de Investigación (España)
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Elsevier BV 2024
• Subjects: 2022 Hunga-Tonga volcanic eruption; Tsunami; Sulzberger ice shelf; Calving pattern; Antarctic; West Antarctica; Pacific; Tonga; Sulzberger Ice Shelf; Gage; Antarc*; Antarctica; Ice Shelf; Iceberg*; Sea ice
• Online Access: http://hdl.handle.net/10261/371670; https://doi.org/10.1016/j.epsl.2024.118958

On January 15, 2022, the eruption of the Hunga-Tonga volcano unleashed a tsunami that rapidly traversed the Pacific Ocean, soon reaching the Sulzberger Ice Shelf (SIS), West Antarctica. In the aftermath, the West Sulzberger Ice Shelf (WSIS) experienced a significant calving event, shedding 106 km of ice and reducing its size to the smallest recorded since 1948. To investigate the potential association between this calving event and the tsunami, and to elucidate the long-term evolution of the WSIS, this study employed tide gage records and remote sensing data for an extensive cross-cycle observation spanning 74 years. The results indicate that post-2014, the WSIS exhibited heightened instability, manifesting as an increased frequency of calving events, a shift from an expanding to a contracting shelf area, and accelerated ice flow velocities (Video S1). The critical rift, instrumental in the 2022 calving, also displayed an accelerated widening rate post-2014, culminating in rapid expansion upon the tsunami's arrival, completing the final 2% of the iceberg's detachment boundary. Modeling results quantify the tsunami induced flexural strains on the ice shelf, with peak values occurring near the region of the subsequent calving event. Notably, multiple calving events during the study period coincided with local minima in landfast sea ice extent, underscoring its protective role for the ice shelf. Furthermore, a significant decline in landfast sea ice near the SIS had been observed over the past two decades, suggesting a weakening of this protective effect. A combination of modeling results and comparative analysis with other similar calving events suggests that tsunamis tend to expedite ice shelf calving predominantly when the shelf is already teetering on instability, which casts a shadow on the SIS's future resilience against natural hazards. © 2024 Elsevier B.V This work was supported by the National Natural Science Foundation of China (42301149), and the Australian Government’s Antarctic Sci- ence ...