Numerical Investigation of Tsunami Inundation Risk Due to the 2018 Anak Krakatau Volcano Subaerial Landslide: Study Case Pandeglang, Indonesia

On December 22, 2018, a devastating tsunami struck Sunda Strait, Indonesia without warning. This incident claimed many lives, particularly in the Pandeglang Regency. Therefore, it is necessary to conduct a tsunami reconstruction to analyze the tsunami risk, which can later be used as a basis for tsunami hazard mitigation. The tsunami reconstruction was carried out using numerical simulations considering seven landslide scenarios for calibration and two inundation model scenarios for comparison. In this study, we introduced a detailed inundation modeling and local risk assessment achieved by incorporating land use data from the national land cover map. The model results were validated against observed water surface elevation and field survey data of inundation heights. It was noted that the best scenario has a landslide volume of 0.326[Formula: see text]km 3 . Among the two inundation model scenarios, it was found that the scenario with spatially varying Manning values was the best model, with an accuracy of 95.39%. From the simulation results, the area with the highest tsunami wave of approximately 7[Formula: see text]m was Tanjung Lesung. This result aligns with the tsunami risk analysis, suggesting that Tanjung Lesung was the most extensively affected area by the tsunami, with a total affected area of 3.225[Formula: see text]km 2 and a risk level 1 area of 0.494[Formula: see text]km 2 . This study highlights the importance of varying spatial characteristics of land use in the tsunami inundation modeling and risk analysis that is often neglected, which can be extended to other areas surrounding the Anak Krakatau.