Coastal geomorphology and tsunami hazard scenario along the Kachchh coast, western India

549-556Geomorphology and coastal configuration plays a vital role during tsunami events as different coastal geomorphic units respond differently to a tsunami hazard. The study of ability of different coastal landforms to respond tsunami surge is very much important for vulnerability mapping of coast. The Kachchh coast that runs for about more than 450 km has conspicuous presence of both, wave as well as tide influenced landforms. Following the classification suggested by Ramasamy et al.1, the geomorphic features for possible response of tsunami event can be classified as facilitators, conveyors, accommodators, absorbers and barriers. Depending upon its action as facilitator, conveyor or accommodator, the geomorphic units like estuary, creek, mudflats and backwater increase the possibility of tsunami run ups and inundation. The beach ridges and wide sandy beaches on the other hand absorb tsunami energy and act as barriers. In view of these six distinct segments have been identified along the Kachchh coast and are described for their possible response to tsunami event. Accordingly, the segment between Jakhau and Suthari has barrier kind of geomorphic set up with presence of backswamps that has higher preservation potential of tsunami deposits. The segment from Suthari to Kanthada has steep beaches and dune ridges that can reduce the intensity of tsunami hazard. The Kanthada - Rawal Pir segment has Rukmavati River mouth that can convey the effect of tsunami to a considerable landward area whereas, the Rawal Pir - Mundra and Mundra – Tuna segments have dominant accommodator type of geomorphic assemblage that also has a higher preservation potential for tsunami sediments. The segment between Tuna and Kandla has relatively much wider mudflats and mangrove swamps which accommodates as well as reduces tsunami energy. However, the configuration suggests much intensified tsunami surge that can devastate the large scale developments in this part. Response mechanism of the coastal geomorphic assemblages will not only help in the disaster risk reduction activities but will also be useful in better understanding of palaeo and historical tsunamis