Comparative study of granulometric and granule trend of pre- and post-tsunami sediments with recent beach sediments from Nagoor to Poompuhar, Tamil Nadu

Abstract

The December 26, 2004 tsunami waves caused significant destruction that changed geomorphic characteristics in India�s east coast. The article presents a comparative study of granulometric and granule trends of pre-tsunami (December, 2004) and post-tsunami (January, 2005) sediments with recent beach sediments (December, 2022) in eight locations, namely, Poompuhar, Chinnankudi, Kuttyandiyur, Chandrapadi, Kottucherimedu, Karaikal Beach, Vadakku Vanjiyur North, and Nagoor Beach. The study was conducted using R Programming and aimed to understand the sediment transport and depositional processes. The textural parameters of the sediments imply that they are becoming relatively finer, stating that the beaches are recovering and reclaiming their regular depositional environment after the disaster. The linear discriminate function plots of pre-tsunami sediments have the highest percentage of aeolian deposits, followed by post-tsunami. The recent sediments have the maximum deposition by the beach environment, and pre-tsunami sediments have the minimal. CM plots show that the transportation of sediments by rolling is more in recent days, whereas sediments were transported by bottom suspension and rolling and by graded suspension in pre- and post-tsunami environments. Further, this study compared sediment roundness between the pre- and post-tsunami periods and the recently deposited sediments. This paper highlights the sediment characteristics observed, especially in the aftermath of natural disasters such as tsunamis. Research highlights: The study provides valuable insights into the origin of the debris, historical transportation, and depositional activities along the coast. The study of pre-, post-tsunami and recent beach sediments along the coast from Nagoor to Poompuhar have been done, in which, the sediments have become relatively coarser from pre to post tsunami deposition condition and in recent deposition, the sediments are becoming relatively finer. The pre-tsunami sediments have the highest percentage of aeolian deposits, followed by post-tsunami. In contrary, recent sediments have the maximum deposition by beach environment. The transportation of sediments by rolling is more in recent days. The beaches are recovering and reclaiming their regular depositional environment in recent times after the disaster which is evident by this study.