Coupling sea-level rise with tsunamis: Projected adverse impact of future tsunamis on Banda Aceh city, Indonesia

The 2004 Indian Ocean tsunami had a significant impact on the city, resulting in widespread destruction and loss of life. This research investigates the potential impacts of future tsunamis on Banda Aceh city, taking into account the effects of sea-level rise (SLR) and various tsunami scenarios. Numerical simulations were conducted using the Cornell Multi-grid Coupled Tsunami model (Comcot) with six layers. Six earthquake magnitudes were used, ranging from Mw 8.2 to 9.15, with the largest magnitude corresponding to the 2004 Indian Ocean tsunami. The SLR rate in the region is 7 mm/year, and the simulations projected the impacts of SLR and tsunamis for 50, 100, 150, and 200 years. The SLR was also combined with three types of tides: lowest-low water level (LLWL), mean sea level (MSL), and highest-high water level (HHWL). The research simulated 100 tsunami scenarios, including two land-use cover periods: 2004 Land Use and Land Cover (LULC) and the 2029 LULC. The latter is part of the long-term city plan for Banda Aceh, which aims to be implemented by the end of 2029. The results showed that the impact of tsunamis triggered by earthquakes with magnitudes of 8.2-8.6 could be doubled if combined with the effects of SLR. The study found that the city's vulnerability to tsunamis is exacerbated by SLR, which can increase the impact of tsunamis by up to 100%. The research highlights the need for effective disaster risk reduction and mitigation strategies to mitigate the adverse impacts of future tsunamis on Banda Aceh city. The findings of this study can inform the development of more effective tsunami early warning systems and evacuation plans, as well as the implementation of sustainable urban planning and infrastructure development in the region. The research emphasizes the importance of considering the combined effects of SLR and tsunamis when assessing the risk of disasters in coastal cities like Banda Aceh. The study's results can contribute to the development of more effective disaster risk reduction and mitigation strategies, ultimately reducing the vulnerability of the city to future tsunamis.