EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Rift Initiation via Unstable Basal Crevasses

Niall Coffey1, Ching-Yao Lai1,2, and Yongji Wang2
Niall Coffey et al.
  • 1Princeton University, Program in Atmospheric and Oceanic Sciences, Princeton, United States of America
  • 2Princeton University, Department of Geosciences, Princeton, United States of America

Ice shelves, the floating extensions of ice sheets, can reduce the rate of sea level rise by buttressing the upstream grounded ice. However, calving, or the fracturing that creates icebergs, can cut out regions that were resisting flow, and allow for increased ice flux and thus sea level contribution. In this work, I focus on the transition from basal crevasses, or seawater-filled fractures on the bottom surface, to full thickness fractures called rifts. Using RACMO ice shelf surface temperatures and holding the ice-ocean interface at -2℃, I find good agreement between observed rifts on the Larsen C and Ross Ice Shelves and rifts predicted to evolve from basal crevasses through 2D Mode I Linear Elastic Fracture Mechanics (LEFM). I also explore the influence of ice shelf geometry in rift formation by solving the Shallow Shelf Approximation (SSA) equations for idealized ice shelves with COMSOL’s Finite Element Analysis software. Using the stress field outputs with LEFM’s rift initiation criteria, I find qualitative agreement in the rift orientation between the predicted unstable basal crevasses and the observed rifts on the left margin of Pine Island Ice Shelf.

How to cite: Coffey, N., Lai, C.-Y., and Wang, Y.: Rift Initiation via Unstable Basal Crevasses, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-8261,, 2023.