Modification of Tsunami Wave by Submarine Canyon: Case Study of Multiple Canyons at South East Coast of India

Abstract

The behavior of natural hazards such as storm surge, tsunami on the coast depends on geomorphological settings of the coast as well as the shelf. The intensity of these events can be modified by features such as estuaries, bays and other coastal configurations. It has been observed that the maximum surge height is found in areas where the shelf is wide and shallow. While the modification of a tsunami in bays, gulfs and river mouths has been investigated, the interaction of tsunami with submarine canyons has not been studied. In this paper, numerical modeling of tsunami propagation was made for the coast wherein submarine canyons are present using nonlinear finite difference model TUNAMI—N2. The data required for the analysis were collected from various sources and a numerical model was run for the event of the December 26, 2004, tsunami. The study clearly indicates that the presence of submarine canyon reduces wave height leeward of the canyon.

Keywords:

• Tsunami
• numerical modeling
• submarine canyons
• wave height modifications
• Bay of Bengal

Acknowledgements

We extend our deepest gratitude to Dr. B. R. Subramanian, Project Director, ICMAM-PD, MoES, for his permission to carry out the work in his project Directorate. We are also thankful to Dr. S. P. Mohan, Professor and Head, Department of Geology, University of Madras, for giving computation facilities. The work forms part of the project Data processing for Tamil Nadu northern districts for modeling and mapping to establish Early Warning System for Tsunami and Storm surges in Indian Ocean awarded by Ministry of Earth Science, Government of India.