Mild Slope Equation for Weakly compressible ocean interacting with a viscoelastic sedimentary layer

What is it about?

Studies, especially in the last decade, have shown that tsunami modeling can be significantly improved considering the compressibility of water column, particularly during generation stage. Up to this point, three-dimensional models were the most straightforward tools at a trackers’ disposal, but, given the time constraints when dealing with tsunamis, they were found to be too time-consuming. The problem was compounded by viscous sediment layers on the bottom of the sea floor, which have a strong influence on hydro-acoustic wave propagation over large distances. To address these issues, I proposed the depth-integrated Mild Slope Equation for Weakly Compressible fluid, MSEWC for a rigid bottom, which reduces the computational problem from three to two dimensions, thereby lowering computational costs. Expanding its capability, the issue of bottom damping was incorporating the sediment layers' effects, which lead to a Mild Slope Equation for Dissipative Weakly Compressible fluids (MSEDWC). Modeling results showed that this improvement of the equations significantly improved the model's prediction compared to real measurement during Tohoku 2011 tsunami. The added complexity of the sediment layer rheology leads to both the lowering of dominant spectral peaks and wave attenuation across the full spectrum. The mild slope equations are published in two articles in the Journal of Fluid Mechanics.

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