This paper describes a multi-scenario, deterministic analysis of the seismogenic tsunami hazard to Bangladesh from active subduction zones in the Indian Ocean region. Two segments of the Sunda arc, namely Andaman and Arakan, appear to pose a tsunamigenic seismic threat to Bangladesh. High resolution numerical simulations of tsunami propagation towards the coast of Bangladesh have been carried out for eight plausible seismic scenarios in Andaman and Arakan subduction zones. The numerical results have been analyzed to obtain the spatial variation of the maximum tsunami amplitudes as well as tsunami arrival times for the entire coastline of Bangladesh. The results suggest that the tsunami heights are amplified on either side of the axis of the submarine canyon which approaches the nearshore sea off Barisal in the seaboard off Sundarban-Barisal-Sandwip. Moreover, the computed tsunami amplitudes are comparatively higher north of the latitude 21.5o in the Teknaf-Chittagong coastline. The calculated arrival times indicate that the tsunami waves reach the western half of the Sundarban-Barisal-Sandwip coastline sooner whilst shallow water off the eastern half results in a longer arrival time for that part of the coastline, in the event of an earthquake in the Andaman seismic zone. On the other hand, most parts of the Chittagong-Teknaf coastline would receive tsunami waves almost immediately after an earthquake in the northern segment of the Arakan seismic zone.
Keywords:
Coastal flooding, Disaster risk mitigation, Numerical simulations, Indian Ocean region
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