Fracture and Calving Front Evolution: A Case Study of Fimbul Ice Shelf, Antarctica

This study combines historical records, satellite remote sensing data, and inverse modelling to investigate crack formation and calving front evolution of the Fimbul Ice Shelf, Antarctica. Historical maps from the 1950s, together with satellite imagery from 1970s–2026, are used to reconstruct calving‐front positions and track the evolution of crevasses. Principal stress fields obtained from higher‐order three‐dimensional inverse ice‐flow modelling support the fracture analysis. The ice shelf is strongly controlled by ice rises of varying size, which act as pinning points and promote fracture formation. The observed fractures consist predominantly of mode I cracks and wing cracks generated by mode I fractures subjected to shear stresses. Our results indicate that the present‐day calving front of Trolltunga is a remnant of the last major calving event in 1967, subsequently modified by collisions with drifting icebergs. We identify crack formation associated with ice flow past ice rises, occurring both immediately downstream of grounded features and at distances of approximately 8–18 km upstream of the present calving front. Fractures initiated at these ice rises play a key role in shaping the lateral margins of Trolltunga. A small grounded feature controls the shape of its eastern calving front, while the western margin is influenced by wing cracks developing within the western shear margin of Jutulstraumen and by mode I cracks originating near the Apollo Ice Rises. No significant change in fracture formation along the calving front is identified over the past five decades, providing no evidence of substantial present‐day structural change.