Tsunami identification from surface data: a Tikhonov-Morozov mixed formulation

par M. Laurent Bourgeois (CentraleSupélec, Université Paris-Saclay, Sorbonne Université)

mardi 3 déc. 2024, 14:15 → 16:15 Europe/Paris

Considering a simple linear model of ocean, we wish to identify the bottom deformation due to a tsunami from the observation of the perturbed free surface. In this preliminary work, we restrict to a time harmonic situation. This ill-posed problem is addressed with the help of a mixed formulation of the Tikhonov regularization, the Morozov principle being used to compute the regularization parameter through a duality approach. One step of this Morozov process requires to compute a lifting function which is associated with some noisy Neumann data and convert the noise amplitude of the surface data to a noise amplitude of the volume lifting function. We compare a deterministic and a probabilistic conversion, the second one improving the quality of the identification.