Is the Northern Bay of Bengal Tsunamigenic?

The giant tsunami generated by the great 26 December 2004 Sumatra-Andaman earthquake and the resultant destruction have necessitated appropriate assessment of tsunami potential in the northern Bay of Bengal, where high population density in the coastal area (similar to 100 million) makes this region very vulnerable if a large tsunami were to occur. Here we examine whether the India-Burma plate boundary in the Arakan and Irrawady region can produce a tsunamigenic earthquake. We find: (a) the region is characterized by oblique plate motion leading to strike-slip dominated earthquakes with low tsunami generating potential; (b) the deformation front associated with the plate boundary between India and Sunda plates in the northern Bay of Bengal is either landward or in shallow water in the Arakan region and, hence, a great earthquake is unlikely to displace large amounts of water to create a significant tsunami; (c) convincing evidence that the 1762 Arakan earthquake generated a large tsunami is lacking; and (d) no large tsunami has affected the region in the past 2000 years. We conclude that while a great earthquake could occur in the Arakan region, the physiographic situation may not lead to generation of a large tsunami.