A comparative study on the style of paleotsunami deposits at two sites on the west coast of India

Based on field documentation, we produce a comparative analysis of soft sediment deformation and other sedimentary signatures indicative of paleotsunami at two beach sites on the west coast of India. Trench profiles from these sites depict major differences in morphology of the structures as a result of greater overpressure from terrigenous backwash deposition at Dive Agar compared to Guhagarh, where the backwash flow escaped through an estuarine outlet. The occurrence of sporadic boulders, wedge-shaped heavy mineral sand layers and capping of the deposit by a pedogenic surface at Guhagarh depicts an older tsunami of larger magnitude compared to Dive Agar. The collective orientation of the characteristic signatures suggests two different sources of tsunami at Dive Agar (from Sunda arc in the SE) and Guhagarh (from Makran in the NW) that are further modeled to suggest the probable paleo-oceanographic conditions. The style of paleotsunami signatures are thus indicative of the coastal response to the arriving tsunami which is further controlled by the direction of source and the morphology of the coast. The study of paleotsunami records therefore provides useful information on the local coastal response to an arriving tsunami which is essential for vulnerability studies and better preparedness. Copyright Springer Science+Business Media Dordrecht 2013