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.