Tsunami Hazard Mapping and Evacuation Path Determination using field Survey and Geographical Information Systems at Widarapayung Wetan, Cilacap

¹ Agency of Meteorology Climatology and Geophysics (Banjarnegara Geophysics Station)
² Civil and Environmental Engineering, University of Gadjah Mada
³ School of Earth and Environment, University of Leeds

Abstract

In 2006, a tsunami hit Pangandaran, and its effects were felt in Cilacap. There were 664 fatalities, 498 injuries, and 55 million dollars in damages, and 1623 homes were destroyed or severely damaged due to the tsunami. Furthermore, the village of Widarapayung was among those devastated by the tsunami, which reached a height of up to 5 meters and claimed the lives of 12 people. In addition, Widarapayung is a popular tourist destination and one of the venues for 2019’s professional surfing events. Therefore, disaster prevention measures are essential to lessen the impact of disasters and save lives. The objective of this study is to assess the vulnerability of the Widarapayung Wetan area to a tsunami and make recommendations for evacuation routes and regional infrastructure development to reduce casualties and damage. This research utilized COMCOT to model the megathrust segment with a possible magnitude of 8.7, with worst-case values acquired from the catalog PuSGeN 2017. Additionally, the data on topography and bathymetry collected by DEMNAS and BATNAS are utilized in this investigation. The modeling results indicated a 50-minute arrival time for the tsunami waves, a maximum run-up height of 14-18 meters, and a submerged area of roughly 4.57 km2. In addition, the most effective evacuation routes were determined by combining the outcomes of field surveys and Geographic Information System simulations. This research will provide local governments with helpful information for making informed decisions about infrastructure and spatial development in the future.