Michael Berry
Bristol University
7 mars 2008 de 16 h 00 à 18 h 00 (heure de Montréal/HNE) Sur place
Colloque par Michael Berry (Bristol University)
For most of their propagation, tsunamis are linear dispersive waves whose speed is limited by the depth of the ocean and which can be regarded as a diffraction-decorated caustic in spacetime. For constant depth, uniform asymptotics gives a very accurate compact description of the tsunami profile generated by an arbitrary initial disturbance. Variations in depth can focus tsunamis onto cusped caustics, and this "singularity on a singularity" constitutes an unusual diffraction problem, whose solution indicates that focusing can amplify the tsunami energy by an order of magnitude.
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