Post-tsunami adjustment of coral reef platform and other morphometric changes in Landfall Island, North Andaman—An integrated field and remote sensing-based approach

Abstract

Coral reefs are active areas of scientific interest. Globally, coral reefs are declining due to enhanced sea surface temperature, rapid sea-level rise and other tectonic-climatic factors. In this paper, we have presented tectonic control for coral reef morphodynamics over the northern part of Andaman, Landfall Island. The 2004 Sumatra earthquake of Mw 9.1 posed essential changes on the overriding plate. Consequently, the Landfall Island changed its pattern of neotectonic movements. Here, we collected multi-temporal regional proxies like shoreline change rate, reef upliftment rate, and coral reef geomorphology for systematic tracking of earthquake-induced changes for various short-term [inter-seismic (1987–2004), co-seismic (2004–2006), early post-seismic (2006–2009), post-seismic (2009–2014)] and long-term [inter-seismic to post-seismic (1987–2014)] durations. Maximum upliftment rates (0.24 m/yr) and shoreline change rates (108.2 m/yr) with comparable geomorphic variations were noticed in co-seismic time. Other short-term changes are primarily related to earthquakes, wave actions and local geomorphology change. Additionally, we have reported new zones of adaptation for live corals. Our field survey and geodetic study verified remotely-derived morphologic adjustment of coral reefs.