A viscoelastic model of ice stream flow with application to stick-slip motion

• Published in: Frontiers in Earth Science
• Main Authors: Ryan Thomas Walker, Byron eParizek, Richard eAlley, Sophie eNowicki
• Format: Article in Journal/Newspaper
• Language: English
• Published: Frontiers Media S.A. 2016
• Subjects: viscoelasticity; STICK-SLIP; Ice rheology; Whillans Ice Stream; ce stream dynamics; numerical ice sheet modeling; Science; Q; Whillans; Ice Sheet
• Online Access: https://doi.org/10.3389/feart.2016.00002; https://doaj.org/article/bc0e10bf50584302a5808dcb1e1ce653

Stick-slip motion such as that observed at Whillans Ice Stream, WestAntarctica, is one example of transient forcing significantly affecting longer-termice-stream dynamics. We develop and present a two-dimensional map-plane viscoelasticmodel of perturbations to ice-stream dynamics suitable for simulating andanalyzing stick-slip behavior. Model results suggest important roles in stick-slipmotion for both the elastic and viscous components of ice rheology, confirming andextending inferences drawn from simple models and observations. Elastic behaviordepends on the rate of applied stress, at times allowing significant velocity perturbationswith little change in accumulated stress perturbation; in contrast, viscousbehavior depends on total accumulated stress and can lead to changes in ice-streamthickness over many stick-slip cycles.