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In a disaster event, the impact of the tsunami is measured based on wave height along the coast. During its propagation towards the coast, tsunami wave that develop in the ocean will be amplified due to shoaling. The elevated waves that struck residents in Palu Bay were very severe, far exceeding predictions. Recent research shows that the strike-slip earthquake on 28 September 2018 (Mw 7.5) along the Palu-Koro fault caused several landslides in Palu Bay, which then triggered a significant tsunami wave. Closer investigation, the extreme height of tsunami in Palu Bay was due to geographical factors such as narrowing of the bay, and the presence of a bump in the mouth of the bay, both of which have the same effect, namely wave focusing. Our study here is focused on the effect of bathymetry on wave focusing in bays. The momentum conservative scheme with wet-dry procedure was implemented here to solve the 2-dimensional shallow water model. The scheme is validated via simulation of wave amplification in an (idealized) parabolic bay, to be compared with the existing analytical solution. Next, wave amplification due to a bump on a flat topography will be evaluated. Finally, wave amplification in the mouth of Palu Bay using real topography will be assessed.