Far field tsunami simulation using an open boundary condition from an extended domain

Abstract

This study assesses the simulation of far field tsunami from an extended domain along the coastal belt of Southern Thailand and the west coast of Peninsular Malaysia using a formulated open boundary condition. The vertically integrated depth averaged shallow water equations are solved numerically in two different model domains. Along with the original domain (OD) an extended domain (ED) is considered during the simulation process. Using the method of lines technique, linear shallow water equations (SWE) are solved in the original domain and the extended domain all together to simulate the response of the tsunami source in the western side of the open boundary of the original model domain. A tsunami source similar to 2004 Indian Ocean Tsunami is considered as an initial condition for this boundary value problem. The ED is extended up to 2000 km from the coast. The non-linear shallow water equations are solved in the original domain where the tsunami source was omitted. In the original domain, a boundary condition is used which was formulated by the amplitude of the source in the extended domain and the formulated boundary condition was imposed at west boundary of the OD to compute tsunami response in absence of original tsunami source. Finally, the effect of the formulated boundary condition was simulated in the coastal belt of the south part of Thailand and the west coast of the Peninsular Malaysia. Tsunami travelled time and water elevation for different coastal location are stimulated by the two models. The outputs of this study are compared with the available data in the USGS website, and a very reasonable agreement is observed.