Figure 7 . Changes of modeled flow velocities (a–h) and backstresses (i–p) in response to the front geometry changes (non-rift scenario).
5.3 Longitudinal deviatoric stress field and rift opening (non-rift scenario)
We find that the modeling scenario considering only the front geometry condition is also useful to diagnostically predict the rift opening location. Figures 8a–b show the longitudinal deviatoric stress fields for F2 (2000 front) and F3 (2013 front), with positive values representing tensile conditions along the flow direction and negative values for compressive conditions. The locations where rifts opened strongly coincided with the transitional zone from compressive to tensile longitudinal conditions, including the rift near Bawden Ice Rise (Figure 8c) that caused the northern calving event in 2004/2005, and the rift R2 (Figure 8d) whose expansion to Gipps Ice Rise directly related to the rift R1 and eventually caused the 2017 calving event. This transitional pattern appears to be a characteristic feature near ice rises. Although we did not account for the rift-induced weakening effect on ice rigidity, the longitudinal deviatoric stress field may be used as an important diagnostic feature to identify potentially vulnerable areas that are favorable for rift opening, especially within the transitional zone from compressive to tensile conditions. Identifying the potential locations of the initial rift opening is a necessary step for introducing rift-caused damage into ice shelf models.