Building Vulnerability Analysis Due to Tsunami by Using Probabilistic Tsunami Hazard Assessment (PTHA): A Case Study of Pelabuhan Ratu, Sukabumi

Cities that vulnerable to tsunamis, including the village of Pelabuhan Ratu on the southern coast of West Java, Indonesia, are in dire need of adequate vertical evacuation structures. However, constraints regarding to limited funding and difficulties in finding affordable land have hindered the implementation efforts of such structures in several cities. This research aims to analyze building vulnerability to tsunami disasters and identify buildings that can serve as alternative tsunami evacuation options based on Probabilistic Tsunami Hazard Analysis (PTHA) in Pelabuhan Ratu. The research methodology involves mapping the Modified Building Tsunami Vulnerability (BTV) and connecting the numerical simulation results with fragility curves assumed for the Pelabuhan Ratu area. The numerical simulations were conducted using the Cornell Multi-Grid Coupled Tsunami Model (COMCOT). Various tsunami scenarios triggered by earthquakes with different magnitudes ranging from 8.5 to 9.0, with intervals of 0.1, were considered in the numerical simulations. The research findings indicates high probability of maximum tsunami height reaching 14.85 meters in a return period of 10,000 years, and 51.77 meters in return period of 30,000 years. Based on these results, it was found that a three-story minimarket built with concrete could be used as an evacuation facility in a 10,000-year return period.