Effect of Submarine Canyons on Tsunami Heights, Currents and Run-Up Off the Southeast Coast of India

Tsunami numerical model studies are mostly focused on inundation and run-up onto the coast. Fewer studies have been aimed at investigating the role of submarine canyons on tsunami heights, currents and run-up. The tsunami hydrodynamics in the vicinity of submarine canyons and ridges in the Palar-Cauvery region off the southeast coast of India on 26 December 2004 is considered in this study. Numerical modelling was carried out to study tsunami heights and currents in the vicinity of the submarine canyons as well as the variation of tsunami heights at 10 m water depth. Comparisons between the tsunami wave energy density at 10 m depth and the onshore run-up height observations showed good correlation for select locations, with the run-up heights being about 3% of the wave energy density. However, the local topography in the run-up zone also strongly influences the local run-up, which reduces direct correlations between run-up and nearshore tsunami height.