Tsunami hazard modelling in Sunda strait, West java, Indonesia

Abstract

The Sunda strait, part of The Sunda Megathrust, is one of Indonesia’s most tsunamigenic regions and is recognised as highly susceptible earthquakes and tsunami related hazard. The maximum credible earthquake along this Megathrust is estimated to reach magnitude of 8.2-8.7 Mw. This research examines the tsunami hazard in Cilegon city, Banten, which lies directly on the coast of the Sunda strait. The objectives are to estimate tsunami wave run-up height and to analyse potential inundation zones resulting from tsunami waves in Cilegon city. The method involves tsunami modelling using three earthquake scenariosmagnitudes 8.2 Mw, 8.45 Mw and 8.7 Mw employing the COMCOT (Cornell Multi-grid Coupled Tsunami Model) software, complemented by H-loss calculations. Results derived from a geographic information system (GIS)-based hazard analysis, integrating COMCOT outputs and H-loss computations, indicate that the overall tsunami hazard in Cilegon city is relatively low. The estimated wave arrival times at the Cilegon coastline for the three scenarios are 141.9 minutes, 150 minutes and 84.2 minutes respectively. In all cases, modelled run-up heights not exceed 3 meters and the potential inundation area remain under 200 hectares, affecting the districts of Ciwandan, Citangkil and Grogol.