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The Sagar is the largest inhabited island in the Ganges delta in India. In the recent decades the island experiences severe stress and coastal instability due to multiple setbacks such as high erosion, degradation of coastal vegetation, frequent cyclones, dynamic changes in land features and rapid population growth. This study aims in assessing the spatial dynamics of the land features of the island during the past 45 years from 1972 to 2017 as two scenarios i) Short-term and ii) Long-term to evaluate the impacts on its coastline. The extended aim of the study was to predict the status of the land features in the island for the next two decades, ie 2027 and 2037 using CA–MARKOV model. The study indicated continuous loss of land to sea and depletion of coastal features such as mangroves, mudflats and sand dunes in both the scenarios. In view of the continuous erosion of the island’s coast, protective embankments have been constructed to protect life and property. The study indicated damage of embankments due to erosion over time. Analysis of recent changes indicated that strengthening the existing embankments together with restoration of natural systems such as mangroves would minimize erosion though it may not serve as an ultimate solution to combat erosion. Based on the population density living in close proximity to such eroding coasts along with its prevailing protection measures, the study classified such stretches as hotspots of category I, II and III. [ABSTRACT FROM AUTHOR]

Coastal zone is dynamic in nature and is subjected to multiple interactions from marine, terrestrial, atmosphere, biosphere, fluvial systems and tectonic processes besides human interventions. Each coast is unique to its geographical location and set of physical interactions between land and oceanic parameters. Understanding these interactions are challenging and complicated in perception of its sustainability. A central concept in developing such a holistic approach is to view the coast as discrete functional units termed as ‘Sediment Cells’ rather than viewing it as a single continuous stretch of land surface. Sediment cell approach will provide a better understanding of the interrelation between the functions of the short term coastal processes and long term response and recovery of the coast. Based on sediment cell approach, a study was undertaken to delineate discrete functional units along the west and east coasts of varying spatial scales with confined sediment movement. Long term morphological changes, short term coastal processes and sediment dynamics were considered for the delineation. A total of 26 primary cells with 10 on the west and 16 on the east were identified from the study. These primary cells were further sub divided into 58 sub cells with 21 on the west and 37 on the east based on the sediment interruption factors either natural or manmade. The identified coastal sediment cells can be used in Integrated Coastal Zone Management (ICZM) especially to deal with shoreline changes and in the preparation of Shoreline Management Plans (SMP). To be specific, the delineated coastal sediment cells from the study are being used for the preparation of ICZM plans for Odisha and West Bengal. [ABSTRACT FROM AUTHOR]

The impacts of climate change are of particular concern to the coastal region of tropical countries like India, which are exposed to cyclones, floods, tsunami, seawater intrusion, etc. Climate-change adaptation presupposes comprehensive assessment of vulnerability status. Studies so far relied either on remote sensing-based spatial mapping of physical vulnerability or on certain socio-economic aspects with limited scope for upscaling or replication. The current study is an attempt to develop a holistic and robust framework to assess the vulnerability of coastal India at different levels. We propose and estimate cumulative vulnerability index (CVI) as a function of exposure, sensitivity and adaptive capacity, at the village level, using nationally comparable and credible datasets. The exposure index (EI) was determined at the village level by decomposing the spatial multi-hazard maps, while sensitivity (SI) and adaptive capacity indices (ACI) were estimated using 23 indicators, covering social and economic aspects. The indicators were identified through the literature review, expert consultations, opinion survey, and were further validated through statistical tests. The socio-economic vulnerability index (SEVI) was constructed as a function of sensitivity and adaptive capacity for planning grassroot-level interventions and adaptation strategies. The framework was piloted in Sindhudurg, a coastal district in Maharashtra, India. It comprises 317 villages, spread across three taluks viz., Devgad, Malvan and Vengurla. The villages in Sindhudurg were ranked based on this multi-criteria approach. Based on CVI values, 92 villages (30%) in Sindhudurg were identified as highly vulnerable. We propose a decision tool for identifying villages vulnerable to changing climate, based on their level of sensitivity and adaptive capacity in a two-dimensional matrix, thus aiding in planning location-specific interventions. Here, vulnerability indicators are classified and designated as 'drivers' (indicators with significantly high values and intervention priority) and 'buffers' (indicators with low-to-moderate values) at the village level. The framework provides for aggregation or decomposition of CVI and other sub-indices, in order to plan spatial contingency plans and enable swift action for climate adaptation. [ABSTRACT FROM AUTHOR]

Earthquakes that trigger tsunamis are of great geological, ecological and socio-economic importance. The knowledge of the recurrence interval of these events will give information about the hazard for a region. Coastal sediments on the Andaman Islands located in the eastern Bay of Bengal were investigated to find evidence for palaeotsunamis and palaeoearthquakes. Fieldwork was conducted on Red Skin Island and North Cinque Island, south of South Andaman. Sediment material from event-layers was dated by optically stimulated luminescence and radiocarbon dating method. The results show evidence possibly for one earthquake at about 1,000 or 3,000 years before the present together with deposits from possible tsunamis and storms. The complex pattern of co- and post-seismic uplift and subsidence of the Andaman Islands is reflected in the investigated sections and made it possible to reconstruct an event-history for the last 3,000 years. [ABSTRACT FROM AUTHOR]