Numerical modeling analysis for tsunami hazard assesment in west coast of southern Thailand

This study is intended to know the tsunami effect on the west coast of southern Thailand from potential fault locations in and around Andaman Sea. Four cases of fault were simulated as the tsunami source models. TUNAMI code (TUNAMI-N2) used to compute tsunami propagation in the ocean. For large area (region 1), tsunami was computed using GEBCO 1 arc minute bathymetry by the linear theory in spherical coordinate system with Coriolis force. Finer spatial bathymetry grids resample from GEBCO, 15, 5 and 1.67 arcs second in small area, were used in regions 2, 3 and 4 and the tsunami propagation was computed by the non-linear theory in Cartesian coordinate system with bottom friction term. Calculated tsunami heights and travel times were obtained at following output points namely: two existing DART buoys, eight existing tide gauges, four TMD planning tide gauges and forty assumed tide gauges. The results of Case 1 from linear long wave numerical model have shown that tsunami wave heights were larger than observed data. The results of the non-linear long wave numerical model demonstrated a good agreement with the observed data for tsunami heights and travel times. The results of numerical simulations have shown that the Thai DART buoy is useful to indicate a generation of tsunami. Tsunami arrived at the Thai DART buoy in Cases 1, 2 and 3 before the other tide gauges. This result can be used to improve accuracy of tsunami warning system for preventing false alarm. Moreover, maximum tsunami heights were larger in the Phangnga and Phuket provinces then integrated countermeasures and city planning must be set up to prevent communities along coastal line.