Computation of Seismic Resistance of an Ice Island by the Grid-Characteristic Method on Combined Grids

The goal of this study is to develop and apply a grid-characteristic numerical algorithm for determining damage to an offshore object (ice island) by computing seismic wave propagation from an earthquake hypocenter located at a depth of several kilometers taking into account specific features of the Northern Seas (shallow depths). The grid-characteristic method on combined grids is used for this purpose. A single run involves more than 25 separate grids differing from each other in the system of equations to be solved, the type of the numerical scheme, and the step sizes in coordinates. Some of these grids make up a set of embedded hierarchical ones with a multiple step in coordinate, while the others are conformal to each other. Additionally, an improved nonreflecting condition is used, which assumes a sharp increase in the step size in coordinate and the application of a dissipative difference scheme. Special attention is given to the computational algorithms used on the boundaries and interfaces of the separate grids, which make it possible to implement the proposed approach with the use of the grid-characteristic method on combined grids.