On the contribution of the horizontal sea-bed displacements into the tsunami generation process

Denys Dutykh (1) , Dimitrios Mitsotakis (2) , Leonid Chubarov (3) , Yuriy Shokin (3)

1 LAMA - Laboratoire de Mathématiques
2 IMA - Institute for Mathematics and its Applications
3 Institute of Computational Technologies

The main reason for the generation of tsunamis is the deformation of the bottom of the ocean caused by an underwater earthquake. Usually, only the vertical bottom motion is taken into account while the horizontal co-seismic displacements are neglected in the absence of landslides. In the present study we propose a novel methodology for reconstructing all components of the bottom coseismic displacements field. Then, the sea-bed motion is transmitted onto the free surface using a three-dimensional Weakly Nonlinear (WN) approach. We pay special attention to the evolution of kinetic and potential energies of the resulting wave while the contribution of the horizontal displacements into wave energy balance is also quantified. Approaches proposed in this study are illustrated on the July 17, 2006 Java tsunami and some more recent events.

Mots clés: tsunami waves; water waves; coseismic displacements; wave energy; finite fault inversion

Domaines: Mécanique des fluides [physics.class-ph]; Mécanique des fluides [physics.class-ph]; Océan, Atmosphère; Dynamique des Fluides [physics.flu-dyn]; Physique Atmosphérique et Océanique [physics.ao-ph]; Physique Numérique [physics.comp-ph]; Océanographie; Géophysique [physics.geo-ph]; Géophysique [physics.geo-ph]; Milieux et Changements globaux

Denys Dutykh, Dimitrios Mitsotakis, Leonid Chubarov, Yuriy Shokin. On the contribution of the horizontal sea-bed displacements into the tsunami generation process. 2012. ⟨hal-00530999v3⟩