Résumé
Unexpectedly strong seismic anisotropy measured across the width of New Zealand implies that plate boundaries in continents are much wider than standard plate tectonics predicts. We proposed to test whether lithospheric shearing or asthenospheric flow cause this seismic anisotropy, and to determine how wide the plate boundary is in the crust and in the mantle. To further these aims, collaborative work, in the form of a joint supervised PhD (or cotutelle), was conducted in the Institute of Geophysics at Victoria University of Wellington and in the Laboratoire de Tectonophysique at Universite Montpellier 2 (France).