Numerical modeling of the 2010 tsunami in Concepcion Bay using static non-uniform initial deformation

Abstract

In this preliminary work the 2010 tsunami behaviour in Concepción Bay is studied. To that end, the numerical model TUNAMI-N with a resolution grid of 81", 27", 9" y 3" is used. The initial condition is defined from a non uniform static condition, which is obtained by means of superposition of several uniform deformations calculated following the Okada formulation. The simulation results are compared with measurements of inundation height and records of the sea level by WCATC in the Port of Talcahuano. The results show that there is a good representation of the arrival time and wave amplitude. In the same way, it is observed that the flooded area determined by the numerical model is a good approximation of the observed in the 2010 tsunami. Finally, through the analysis of the results given by the numerical model, it was observed that the first wave had not the highest amplitude and oscillated inside the bay during one hour approximately until the next wave of higher amplitude entered and caused the largest inundation. It is proved, in addition, that the great number of waves recorded in several places inside the bay was due to an internal oscillation caused by the bay own geomorphology.