Widening process and seasonal dynamics of the large-scale rift and its mélange in the 2nd largest ice shelf in Antarctica

Abstract: Rift plays an important role in ice shelf calving event, which forms the boundary of tabular detachments and the acts as precursor for ice shelf calving. Rift m\'elange shows the resistance to deform during rift propagation, which plays the role as stabilizing the rift. However, the detailed 3D propagation process of the rift, including the dynamics motion of its m\'elange, is not clearly investigated since then. In this paper, a long time series of 2D propagation rates are generated to provide an overview of all rifts throughout the FRIS, which reveals that the rift T1 and T2 were quite active and will dominate the next calving event. Then, the process of widening of rift T1 is detailed investigated, which is representative for rift propagation process. By utilizing REMA DEMs and ITS_LIVE ice velocity maps, the process of m\'elange widening and rift wall widening are estimated. The m\'elange widens linearly in space and rift wall widening is caused by collapse. The processes of m\'elange height decreasing and m\'elange widening both reveal linear patterns during rift widening process. Rift widening process shows seasonal variant, which is attributed to the seasonal variant of rift wall widening. However, m\'elange widening reveals a stable trend, which proves its stability. The seasonal variant of rift wall widening is further explained by the collapsing process during different seasons. The process of rift propagation worth long-term monitoring both vertically and horizontally in the future, which is significant for ice shelf calving ice shelf instability studies.