C022-0020
Simulation of flexural-gravity wave response of Antarctic ice shelves to tsunami and ocean wave impacts
Wednesday, 9 December 2020
Poster
Nurbek Tazhimbetov, Stanford University, Institute for Computational and Mathematical Engineering, Stanford, CA, United States, Martin Almquist, Stanford University, Geophysics, Stanford, CA, United States, Yong Wei, NOAA/Pacific Marine Environmental Lab & University of Washington, Seattle, WA, United States, Eric M Dunham, Stanford University, Department of Geophysics, Stanford, CA, United States, Peter D Bromirski, Univ California San Diego, La Jolla, CA, United States and Diego Arcas, NOAA, NOAA Center for Tsunami Research, Seattle, WA, United States
Abstract:
Floating ice shelves off the coast of Antarctica play an important role in buttressing the outflow of grounded ice. The break-up of some ice shelves on the Antarctic Peninsula has been linked to incident ocean wave impacts. Surface gravity waves continuously impact ice shelves and induce vibrational stresses which can induce fracturing or expand existing fractures. Furthermore, observations from recent deployment of broadband seismic arrays on the Ross Ice Shelf demonstrate that trans-Pacific propagating sea swell and infragravity waves induce flexure in Antarctic ice shelves. Numerical modeling of gravity wave impacts on ice shelves is required to interpret the vibrational response measured by seismometers.
Here we formulate a stable high-order finite difference solver for a depth-integrated 2D map-view model of flexural-gravity waves in an incompressible shallow water layer that is overlaid by an elastic ice shelf. Coordinate transforms and unstructured multi-block meshes are used to handle the complex geometry of the Ross Ice Shelf and surrounding ocean. We use a GPU-accelerated algebraic multi-grid solver to solve the discretized linear system. The impact of tsunamis on the Ross Ice Shelf is investigated using Boussinesq-modeled hypothetical tsunami arrivals from Central and South America. Our simulations account for spatially variable bathymetry, water depth, and ice shelf thickness. The model will also be used to quantify the impact of ocean waves on Thwaites Glacier Tongue, which is much smaller than the Ross Ice Shelf, making it more susceptible to long period gravity wave excitation that induces bending stresses along grounding zones.
