Status Report Tsunami and the Effects on Coastal Morphology and Ecosystems: A Report E UMA DEVI and S S C SHENOI* Indian National Centre for Ocean Information Services, Nizampet (S)), Hyderabad 500 090, India *Author for Correspondence: E-mail: shenoi@incois.gov.in Proc Indian natn Sci Acad 78 No. 3 September 2012 pp. 513-521  Printed in India. Introduction The 9.3 magnitude earthquake off coast of Sumatra on 26 December 2004 and the subsequent tsunami in the Indian Ocean caused unprecedented loss to human life and property in the coastal regions of India and neighbouring countries. About 230,000 people perished in the countries along the Indian Ocean rim by the waves thus generated. The disaster raised awareness of tsunamis and prompted nations to support research and equipment. As a consequence, the warning systems setup in the Indian Ocean can now effectively forecast as to when and how the tsunamis will cross ocean basin and hit the coastlines thousands of kilometers away from the location of the earthquake. In India, the research related to tsunami was unheard of prior to the occurrence of the event on 26 December 2004. Mostly, the research related to tsunami dealt with seismicity of the tsunamigenic regions, modeling and observations of tsunami waves, changes in coastal morphology, changes in ecosystems and paleo-tsunamis. A total of 77 research publications from Indian authors appeared in various journals dealing with above aspects during the past four years. The major findings of these research publications are summarized. Seismicity of Tsunamigenic Regions A study by Mishra et al. (2011) based on 3-D P-wave tomography for the entire rupture zone of the Andaman and Nicobar region using the aftershocks of the 2004 Sumatra–Andaman earthquake (Mw 9.3) demonstrated the role of crustal heterogeneity in seismogenesis that caused the strong shakings and tsunamis. Ambikapathy et al. (2010) studied the rupture model of the 2007 Bengkulu earthquake using GPS measurements. The measurements provided estimates of high coseismic displacements reaching 1.2 m. The modeling of this near-field data suggested that the 250 × 100 km 2 earthquake ruptured the gently dipping plate interface with a maximum slip of 7.0 m under the Pagai Island. Majority of the slip on the rupture was confined in the depth range of 13-40 km and the rupture did not extend till the trench. The earthquake, despite its large size, did not generate a major tsunami as most of the high slip occurred under the islands and shallow water, so that the volume of the water displaced by the coseismic uplift was too low to cause any major tsunami. Jaiswal et al. (2011) studied the aftershock sequence of the 2004 Sumatra earthquake and simulated the 2007 Bengkulu earthquake and showed that as the path of the tsunami for Indian coastlines was oblique; hence, no impacts along the Indian coastline except near the coast of epicentral region. Study of multi-sensor temporal satellite data of pre- and post earthquake period for six months around Andaman and Nicobar Islands revealed that northwestern part of the Island Belt experienced emergence of landmass while major parts of South Andaman, part of Little Andaman and islands of Nicobar Group suffered submergence. Further study for a period of six months following the main shock, established that the uplifted northwestern part of the Tsunamis are one of the most destructive natural hazards that affect the coastal areas. Tsunami waves that impact the coast with enormous energy are capable of destroying the objects on the coast and re-shaping the coastal geography, geomorphology and ecosystem. These waves can also cause extensive damage and disruption to human lives, their livelihood, infrastructure and economic activities. The 26 December 2004 Sumatra-Andaman earthquake, one of the largest recorded and deadliest tremor, created an unparalleled catastrophic tsunami wiping out thousands of human lives and throwing millions homeless. This event attracted the interest of several geosc ientists in India and stimulated extensive scientific research. This article summarizes the tsunami related research work carried out in India during the past four years. Key Words: Tsunami; Earthquake; Sumatra & Makran Subduction Zones; Numerical Modeling; Coastal Morphology; Coastal Vulnerability; Ecosystems