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

Abstract

This research is aimed at investigating the impacts of sea-level rise (SLR) and tsunamis on Banda Aceh using several long-term scenarios based on the Sunda mega-thrust, the source of the 2004 Indian Ocean tsunami. Six earthquake magnitudes—Mw 8.2, 8.4, 8.6, 8.8, 9.0 and 9.15—were used to perform a number of numerical simulations using Cornell Multi-grid Coupled Tsunami model (COMCOT) with six simulation layers. The largest magnitude is from the earthquake that triggered the 2004 Indian Ocean tsunami. The sea level in the region rises at the rate of 7 mm/year. This research used the SLR rate to project the impacts of SLR and tsunamis for 50, 100, 150 and 200 years. The SLR rates were also combined with three variations of tides, namely at lowest-low water level (LLWL), mean sea level (MSL), and highest-high water level (HHWL). One hundred twenty tsunami scenarios that included two land-use cover periods—2004 Land Use and Land Cover (LULC) and the 2029 LULC—were simulated. The latter is stipulated in the long-term city planning of Banda Aceh is to be implemented at the end of 2029. This research found that the impact of the tsunamis triggered by 8.2–8.6 magnitude earthquakes could be doubled if they are coupled with impacts of SLR.