Tsunami Wave Transformation in Selesung Bay (Lampung)

The 2018 Sunda Strait tsunami is categorized as a volcano tsunami that happens due to Mount Anak Krakatau’s flank collapse. The modeling effort with this kind of tsunami is challenging. Selesung bay is located in Legundi Island, one of the suffered islands from the tsunami in the Krakatoa water area. This research tries to do a local scale simulation of the bay’s tsunami waves using shallow water wave simulation software. The model permits wave transformation simulation in the bay from the offshore side to the coastal point. The result presents that the inundation height of the tsunami in Selesung bay is a combination of wave height (1.5 m), water depth (1.65 m), and wave set-up (0.2 m). Those properties are summing up 3.4 m modeled inundation height, which is committing to less than 1% error from the measured data of 3.38 m. The model also gives an insight into the diffracted wave condition in Selesung bay with a wave height of 2.8 m and a wave period of up to 25 s. All in all, the model shows a good agreement with measured data and permits the benchmarking points for further study.