International Conference on
Simulation & Modeling

"Towards sustainable livelihood and environment"

How numerical simulations may contribute to a better identification of the triggering source and to the tsunami risk preparedness; the 26 December 2004 Indian Ocean event and the Thailand case study  

BY  
Dr. Mansour Ioualalen 1 and Assoc. Prof. Jack Asavanant 2  
1 Institut de Recherche pour le Developpement, IRD, G?osciences Azur, Villefranche-sur-mer, France
2 AVIC, Dpt of Mathematics, Chulalongkorn University, Bangkok, Thailand

Abstract

The tsunami information can be derived from hydrodynamic observations, e.g. tide gauge records or the anomaly of sea level obtained with altimeters, but also through numerical modeling of the wave propagation. This information may presents useful features.   Once a well constructed numerical simulation is achieved, the computed wave sequence, compared to available hydrodynamic observations, may help in a better characterization of the tsunamigenic source, e.g. earthquakes or landslides among the most widespread ones. For the case of an earthquake, it may be used for refining the rupture parameters derived from seismological instrumentation (GPS positioning, seismic stations analysis). It may also help in identifying the best geophysical source candidate for particular tsunami triggerings when several potential sources are identified: this can be the case when a potentially tsunamigenic earthquake has provoked a landslide.   Then, a better identification of source parameters along with a reliable ensemble of numerical simulations of the tsunami propagation and runup within an area is useful for tsunami risk assessment, e.g. tsunami runup maps and optimization of the tsunami instrumentation for the purpose of a tsunami warning system.   Two cases are considered in this context: the 26th November 1999 Vanuatu and the 26th December 2004 Indian Ocean tsunami events. The latter event is discussed extensively with a focus on the Thailand case study.