COMCOT-Based Tsunami Hazard Assessment for Coastal Run-Up and Inundation Mapping

Abstract

This study aims to simulate tsunami wave propagation and estimate the spatial distribution of run-up and inundation generated by the 2005 Nias–Simeulue megathrust earthquake. The analysis was conducted using the COMCOT (Cornell Multi-grid Coupled Tsunami Model), integrating high-resolution bathymetric data from BATNAS and topographic data from DEMNAS. The earthquake source was parameterized with a moment magnitude (Mw) of 8.6, a rupture length of approximately 300 km, and an average vertical slip of 4.5 m. The simulation results reveal that the maximum sea surface elevation exceeded 5 m near the source region, particularly southwest of Nias Island. Tsunami waves propagated radially with amplitudes strongly controlled by seabed configuration and coastal morphology. Wave heights reached approximately 5.6 m in Nias and 4.7 m in Simeulue, with inundation distances extending 200–250 m inland. Tide gauge analysis indicates that the first wave arrived within 10 minutes of the earthquake, followed by multiple significant waves. The novelty of this study lies in the integration of high-resolution national datasets with COMCOT to enhance the accuracy of tsunami hazard estimation, providing improved predictive capability for coastal risk assessment and supporting more effective mitigation and early warning strategies in tsunami-prone regions.