Geological footprints of the 1945 Makran tsunami from the west coast of India

Abstract

27th Nov 1945, witnessed a Mw ~ 7.8 earthquake which triggered a tsunami in the coastlines of the northern Arabian sea. The 1945 Makran tsunami caused tremendous loss to the coastal communities of Iran, Pakistan, Oman and India. Despite the recent thrust in tsunami research along the western coast of India, the geological signatures of the 1945 Makran tsunami remained elusive. Here we present the first geological evidence of this event inform of a sand-sheet archived in the palaeomudflats of northwestern Saurashtra coast, western India. Based on the optical simulated luminiscence ages and available storm record of the Arabian Sea, the sand horizon seems to be linked with the 1945 Makran tsunami. The documented sand-sheet shows physical, geochemical and biological characteristics such as basal erosional/sharp contact with the underlying unit and lack of sorting along with the presence of mud-clasts. The sedimentary layer also shows an abnormal inland extent of >570 m from the present high-water line. The sedimentary character of the deposit would serve as a templet at other similar activities in the region as well as will contribute to the overall coastal hazard assessment in the rapidly developing region.