  Polar regions are covered by sea ice, which can be seen as a thin solid
elastic sheet with heterogeneous mechanical properties. The dynamics of
deformation of a floating solid sheet are primarly governed by gravity, water
density, and the flexural modulus, which depends on its mechanical properties,
namely the thickness, the Young's Modulus and the Poisson ratio. Non-invasive
methods from seismology can retrieve these three parameters from sheet
deformation dynamics. In this article, we developed another method to extract
locally the flexural modulus of a floating thin elastic sheet from the
spatio-temporal deformations of the sheet. We perform laboratory experiment to
test the accuracy and the robustness of this method on silicon membranes of
controlled mechanical properties. Using patches of different thicknesses and
shapes, we eventually draw maps of sheet thickness, with a sub-wavelength
spatial resolution.
