Disintegration and Buttressing Effect of the Landfast Sea Ice in the Larsen B Embayment, Antarctic Peninsula

The speed-up of glaciers following ice shelf collapse can accelerate ice mass loss dramatically. Investigating the deformation of landfast sea ice enables studying its resistive (buttressing) stresses and mechanisms driving ice collapse. Here, we apply offset tracking to Sentinel-1A/B synthetic aperture radar data to obtain a 2014-2022 time-series of horizontal velocity and strain rate fields of landfast ice filling the embayment formerly covered by the Larsen B Ice Shelf, Antarctic Peninsula until 2002. The landfast ice disintegrated in 2022, and we find that it was precipitated by a few large opening rifts. Grounded glaciers did not accelerate instantaneously after the collapse, which implies little buttressing effect from landfast ice, a conclusion also supported by the near-zero correlation between glacier velocity and landfast ice area. Our observations suggest that buttressing stresses are unlikely to be recovered by landfast sea ice over sub-decadal timescales following the collapse of an ice shelf.