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Vypin, Vallarpadam, and Bolgatty are significant tropical coastal islands situated in the humid tropical Kerala region of India, notable for their environmental sensitivity. This study conducted a comprehensive assessment of shoreline alterations on these islands by integrating Remote Sensing (RS) and Geographic Information Systems (GIS) techniques. Utilizing satellite imagery from the LANDSAT series with a spatial resolution of 30 m, the analysis spanned the years from 1973 to 2019. The Digital Shoreline Analysis System (DSAS) tool, integrated into the ArcGIS software, was employed to monitor and analyze shoreline shifts, encompassing erosion and accretion. Various statistical parameters, including Net Shoreline Movement (NSM), End Point Rate (EPR), and Linear Regression Rate (LRR), were utilized to evaluate these changes. Additionally, the study aimed to discern the root causes of shoreline modifications in the study area, encompassing disturbances and the construction of new structures on these islands. The results conclusively demonstrated the substantial impact endured by these coastal islands, with accretion on both sides leading to the creation of new landmasses. This manuscript effectively illustrates that these islands have experienced marine transgression, notably evidenced by accretion. Anthropogenic activities were identified as the primary drivers behind the observed shoreline changes, underscoring the need for careful management and sustainable practices in these fragile coastal ecosystems. [ABSTRACT FROM AUTHOR]

Many tourists have been recently attracted towards the coasts around the world, especially to the large urban centres and economically significant areas. In the last four decades, there is a significant increase in the key coastal developments and tourist's attractions like major ports, minor ports, fishing harbours, desalination plants, shore protection structures, and many more along the southeast coasts of India, in particular, northern Tami Nadu coastal stretches. The shoreline change study of these regions were carried out using the geospatial technologies (satellite remote sensing and geographical information system) to examine potential modifications occurred during the last 32 years between March 1990 and May 2022. This study used Landsat satellite images of spatial resolution 30 m to track the shoreline changes which was extracted using the Digital Image Processing software and techniques. In addition, the United States Geological Survey (USGS) developed Digital Shoreline Analysis System (DSAS) v5.2 software, an add-on tool to ArcGIS used for the statistical analysis to compute the shoreline rate of change. The linear regression rate (LRR) and end point rate (EPR) statistics were used to identify the eroding, accreting, and stable shoreline between Kattupalli coast and Kalpakkam coast of the northern Tamil Nadu coasts. This shoreline study of 106 km was carried out by dividing it into six zones (zone 1 to zone 6), and the DSAS analysis conveys that the shoreline of zone 1 (Kattupalli) and zone 2 (Ennore) shows erosion compared to other four zones. In locations where the coast is vulnerable, national mitigation measures must be implemented. [ABSTRACT FROM AUTHOR]

Coringa Mangroves in the Kakinada Bay have evolved as the second-largest mangroves in the East Coast of India over the last century. The Coringa Mangrove shoreline has accreted considerably in the past decades as observed from the satellite imageries, adding value to the natural biodiversity of flora and fauna. This study is focused on quantifying the long term changes of Coringa mangrove shoreline using the Landsat imageries for years 1977, 1988, 2000, and 2013 using the Digital Shoreline Analysis System. For a mangrove shoreline length of 20.5 km, 41 transects were cast at an interval of 500 m for calculating the change and their migration distance using three statistical methods, namely End Point Rate (EPR), Net Shoreline Movement (NSM) and Linear Regression Rate (LRR). Results showed that there was considerable growth of mangroves in the bay leading to the seaward migration of the mangrove shoreline from the year 1977–2013. The study observed the difference in the mangrove shoreline migration dynamics in the South-eastern (near the bottom of the spit) and the western part of the Kakinada Bay. The calculated average degradation rate due to erosion is −5.19 m.yr−1 and the average accretion rate leading to their growth is 14.83 m.yr−1 for all transects of the 20.5 km mangrove shoreline stretch during this period. The results hold importance as they help in identifying the regions prone to mangrove degradation and enable management planning for the protection of the eroding stretch of the mangrove shoreline. [ABSTRACT FROM AUTHOR]

Chennai is a major metropolitan city along the southeast coast of India and is popular for its world's second longest sandy beach called as Marina beach the shoreline of which has been gradually advancing towards the Bay of Bengal over a century. The advance of the shoreline is due to the construction of breakwaters for the formation of the harbor of Chennai port, one of the 12 major ports of India. The study area is the stretch of the shoreline between two zones, viz., Zone I: Cooum (13° 4′ N and 80° 17′ 20″ E) and Zone II: Adyar (13° 0′ 49″ N and 80° 16′ 38″ E). The rate of shoreline change over the period 2000 to 2019 is analysed through statistical parameters using geographical information system and DSAS (digital shoreline analysis system) in the form of erosion and accretion. The LRR results elucidate that the Chennai coast has experienced an extremely dynamic feature with an average erosion rate of −1.67 m/year. The accretion due to the littoral drift with an average rate of +1.31 m/year is driven by the net alongshore current towards the north of the Adyar River. [ABSTRACT FROM AUTHOR]

This scientific investigation provides valuable insights into the dynamics of shoreline alteration in the Jagatsinghpur district coast, facilitating informed decision-making for implementing coastal protection strategies. This study presents a comprehensive assessment of shoreline alteration along the 55.045 km stretch of the Jagatsinghpur district coast in India from 1990 to 2020. Landsat 5 TM and 8 OLI satellite image data were used for the analysis. The quantification of erosion and deposition shoreline change rates are computed through a semi-automated approach employing four statistical methods SCE, NSM, EPR, and LLR in the Digital Shoreline Analysis System (DSAS). The coastline was divided into four zones at the tehsil level, resulting in the generation of 5149 transects, categorized as Paradip tehsil-I, Abhyachandpur tehsil-II, Ersama tehsil-III, and Balikud tehsil-IV. The analysis revealed significant erosion in specific areas, including Paradip town in Zone I, Nuagan in Zone II, Zone III, and Kusupur in Zone IV. The decision matrix showed an urgent need for erosion rectification in specific regions. The results indicate the necessity of implementing coastal protection measures in Zone III, B, and D subregions in Zone I and D and F subregions in Zone II. Meanwhile, in Zone IV, subregions A and B necessitate attention. [ABSTRACT FROM AUTHOR]

The focus of this research was to assess the shoreline changes by comparing the satellite data from 1980 to 2020. The study area falls in the region between Kodiakarai and Nagapattinam of the east coast of India, which has frequently been distressed by storm surges and cyclones in the Bay of Bengal. The Digital Shoreline Analysis System (DSAS) detects and measures the erosional and accretional shoreline positions through the statistics of the Shoreline Change Envelope, Net Shoreline Movement, End Point Rate, Linear Regression Rate, and Weighted Linear Regression. The results show that the shoreline from Kodiakkarai to Nagapattinam suffered severe erosion of 17.7% in total with an average annual erosion rate of 3.4 m/year from 1980 to 2020 and the rate of erosion ranged between 0.1 m/year to 19.8 m/year. About 90.5% of the total shoreline was faced high erosion during the period between 2000 and 2010. The maximum erosion was about 1061 m from 2000 to 2010, the maximum accretion was found to be 1002 m in transects at Kodiakkarai during 2010 to 2020. After the effect of 2004 tsunami, the corresponding changes in littoral currents caused the drastic erosion and accretion in this shoreline. The DSAS prediction model shows that 19.3% of the current shoreline will erode in 2030. The maximum predicted erosion is 406 m at Kodiakkarai and the maximum predicted accretion is 148 m at Nagapattinam region. The coastal zone from Kodiakkarai to Nagapattinam needs special attention to prevent the erosion and it is recommended to build suitable coastal protection structures along the coast for sustainable development and to execute the coastal zone management for this region. [ABSTRACT FROM AUTHOR]

Information on shoreline changes is important for the planning of coastal protection works and development of infrastructure facilities in the coastal belt. The Thiruvananthapuram-Kochi sandy coastline in Kerala (India) is prone to severe changes in geomorphology. Continuous monthly data on shoreline positions with respect to the reference stations have been available for this study from 1989 to 2003; these data are analyzed for the seasonal, short- and medium-term changes. Results revealed that the magnitude of fluctuation of the shoreline positions varies with respect to the season and stretch. Seasonal fluctuation is maximum during the southwest monsoon, followed by the non-monsoon season. Shoreline changes classified under erosion, accretion, fluctuation, and stable condition are observed at different stations. During the period, maximum and minimum changes due to erosion occurred at Ambalapuzha and Eravipuram, respectively. Annual maximum fluctuation at any station is found to be 0.5-0.9 times that of the maximum fluctuation observed at that station for the entire period. Stretches with shore protection structures behaved differently, exhibiting continuous recession, tendency to arrest recession, fluctuation and advancement of shoreline. The changing trend - maximum and minimum distance to the shoreline - observed at Arattupuzha is unique when compared to that at other study reaches. [ABSTRACT FROM AUTHOR]

The long stretch of coastline on either side of the Indian peninsula is subjected to varied coastal processes and anthropogenic pressures, which makes the coast vulnerable to erosion. There is no systematic inventory of shoreline changes occurring along the entire Indian coast on 1 : 25,000 scale, which is required for planning measures to be taken up for protecting the coast at the national level. It is in this context that shoreline change mapping on 1 : 25,000 scale for the entire Indian coast based on multidate satellite data in GIS environment has been carried out for 1989-1991 and 2004-2006 time frame. The present communication discusses salient observations and results from the shoreline change inventory. The results show that 3829 km (45.5%) of the coast is under erosion, 3004 km (35.7%) is getting accreted, while 1581 km (18.8%) of the coast is more or less stable in nature. Highest percentage of shoreline under erosion is in the Nicobar Islands (88.7), while the percentage of accreting coastline is highest for Tamil Nadu (62.3) and Goa has the highest percentage of stable shoreline (52.4). The analysis shows that the Indian coast has lost a net area of about 73 sq. km during 1989-1991 and 2004-2006 time frame. In Tamil Nadu, a net area of about 25.45 sq. km has increased due to accretion, while along the Nicobar Islands about 93.95 sq. km is lost due to erosion. The inventory has been used to prepare a Shoreline Change Atlas of the Indian Coast. [ABSTRACT FROM AUTHOR]

The Mahadevi hills, located in the axial zone of Cauvery Suture Zone, comprise a sequence of granulite facies rocks represented by garnet-bearing pyroxene granulites and quartzo-feldspathic gneisess interfolded with banded iron formations. Structural mapping with hand held GPS reveals that the Mahadevi hills constitute a mega sheath fold structure exposing well developed easterly plunging extension lineations. Depressional and culmination surfaces are well demarcated in association with elliptical map patterns. The development of the mega sheath fold structure is genetically related to the regional thrust-nappe tectonics, supporting the model of subduction-accretion-collisional history for the evolution of the Cauvery Suture Zone. [ABSTRACT FROM AUTHOR]

Abstract: The Sundarbans is the world''s largest remaining single block of mangrove forest, covering approximately 1millionha (~10,000km2) of the Ganges–Brahmaputra delta along the coastal areas of India and Bangladesh. Sea level rise and alteration of water flows of the Himalayan headwaters are among the major disturbances threatening these coastal areas. But very few studies exist on the dynamics or current status of the Sundarbans coastline. We used Landsat images spanning from 1973 to 2010, and an algorithm that we developed, to consistently estimate the spatiotemporal dynamics of erosion and accretion for four different time intervals and the whole study period. Our results show that the direction and extent of erosion and accretion rates varied throughout the different periods. Erosion was the highest in the 1973–1979 interval, with 23.2km2 year−1 of land loss. However, that rate substantially declined in the following periods, reaching a rate of 7–10km2 year−1. Accretion showed a rate of 10km2 year−1 between 1973 and 1989, but substantially declined to ~4km2 year−1 between 1989 and 2010. Accretion rate has declined in the recent years but erosion rate has remained relatively high. As a result the delta front has undergone a net erosion of ~170km2 of coastal land in the 37years of our study period. These numbers are significantly higher than the previously reported rates and magnitudes of erosion in this area. The methods and maps developed in this study may be helpful in management planning of this vulnerable coastline. [Copyright &y& Elsevier]

Abstract: The Central Indian Tectonic Zone (CITZ) is a ∼700km long orogenic belt in north-central India that demarcates the accretion zone between the Northern and Southern Indian crustal domains. However, the timing of accretion remains speculative. The Chottanagpur Gneiss Complex (CGC), the North Singhbhum Mobile Belt (NSMB) and the Singhbhum Craton (SC) are three crustal units located at the eastern extremity of the CITZ. The CGC, dominated by blastoporphyritic granitoids intrusive into amphibolite- to granulite facies gneisses, is juxtaposed against the greenschist-facies northern metaflysch belt in the NSMB (N-NSMB) north of the Dalma Ophiolite Belt (DOB), along the Northern Shear Zone (NSZ). Both south CGC and N-NSMB exhibit correlated increase in strain and prograde metamorphism towards the NSZ. Laser ablation inductively coupled plasma mass spectrometry U–Pb zircon and U–Th–Pb monazite chemical ages from the southern parts of the CGC lie between 1.1 and 0.9Ga. Monazite from N-NSMB are of similar age. In contrast, zircon from central parts of the CGC away from the NSZ preserves older concordant ages (up to 2.6Ga), and the 1.0–0.90Ga age population is scarcely represented. South of the DOB, the ∼1.0Ga ages are absent in S-NSMB. Instead, monazites from all samples in S-NSMB record a tightly constrained 1.59–1.56Ga high-P metamorphic event, arguably a result of northward subduction of the metaflysch belt. These two terranes were in turn accreted to the CGC at 1.0–0.90Ga. This accretion at the leading edge of the amalgamated SC–S-NSMB block led to the emplacement of expansive granitoids in the CGC. Apparently, the polychronous CITZ orogen marks the gradual closure of a major ocean basin separating the crustal domains of the Northern and Southern Indian blocks during the Meso- and the Early Neoproterozoic era. [Copyright &y& Elsevier]

In the present study, we used multi-temporal satellite images of Indian Remote Sensing Satellites (IRS1D and IRS P6 - Resourcesat) from 1998 to 2005 to monitor the coastal environment of Paradip, east coast of India. The resultant coastal vector maps were used to estimate the geomorphological changes and shifting of the shoreline position. This integrated study is found useful for exploring accretion and erosion processes in the region. The shoreline maps were compared with the 1973 Survey of India toposheets to estimate the changes which have occurred in the region. Results indicate an increase of 7.72 km in shoreline length and a net loss of 18.73 km2 of beach area between the years 1973 and 1998, and 0.46 km reduction in shoreline length and 3.11 km2 increase in beach area between 1998 and 2005. An overall net increase of 7.26 km length shoreline and a net loss of 15.6 km2 was observed between 1973 and 2005. The years 2001, 2002 and 2003 exhibited loss in length of shoreline as well as area of the beach. These years coincided with certain coastal activities carried out in the study region. [ABSTRACT FROM AUTHOR]

The tropical cyclones impact both the eastern and western coasts of India, causing severe socio-environmental problems. This study analyzed shoreline changes and vegetation degradation caused by cyclone Nisarga and monsoon events in Maharashtra coastal zone and Mumbai region, India. In this study, the shoreline change was studied using the Net Shoreline Movement (NSM) statistical technique embedded in the digital shoreline analysis system (DSAS) tool. The effects of the cyclone on the vegetation were mapped using the Normalized Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVI), and the rainfall distribution from Global Precipitation Measurement (GPM) data. The correlation between rainfall data and vegetation loss was analyzed using geographically weighted regression. The results also show that 90% of the events were concentrated in the 80–300 mm classes, being classified as sudden increases. This cyclone caused erosion in 56.32% of the shoreline; the highest erosion level was observed along the coastal zone of Maharashtra (near Mumbai city). Cyclone Nisarga has also impacted the vegetation loss most prominently in the region, with mean EVI in pre-cyclone equal to 0.4 and post-cyclone equal to 0.2. These eco-physical studies using geospatial technology are needed to understand the behavior of changes in shoreline and vegetation and can also help coastal managers plan for resilient coastal systems after the passage of tropical cyclones. [Display omitted] • Shoreline changes and vegetation degradation due to cyclone Nisarga in Maharastra. • Shoreline change assessed using the Net Shoreline Movement statistical technique. • The cyclone effects were mapped through the NDVI and EVI indices. • The shoreline variation was calculated based on the movements along 751 transects. • Cyclone Nisarga caused erosion in 56.32% of the shoreline, mainly in Mumbai. [ABSTRACT FROM AUTHOR]

The long- to short-term morphodynamic response in low-lying coastal wetlands raises serious concerns worldwide about the loss of their biodiversity and ecological ramifications due to change in tidal amplitude and cyclonic events. One such place worth studying is Chilika lake, India, a prominent Ramsar site, the largest brackish water lagoon in Asia, and the second-largest coastal lagoon in the world. It experiences frequent cyclone landfalls and strong littoral drift that tends to open/close the tidal inlet. The goal of this study was to analyze the response of slow onset events such as long- (1952-2020) to short-term (~annual scale from 1989 to 2020) tidal inlet movement, shoreline change (1990-2020 with almost every five-year interval), spit morphodynamics (~annual scale from 1989 to 2020) on ecological ramification in Chilika lake as well as the implications of sudden onset event such as cyclonic landfall. In this study, we used the Digital Shoreline Change Analysis System (DSAS) to compute the statistics of shoreline change rate by calculating end point rate (EPR) values for short-term shoreline change (1990, 1995, 2000, 2005, 2011, 2016, and 2020) and weighted linear regression (WLR) for long-term shoreline change (1990-2020). The results show that Chilika lake experienced both erosion and accretion processes with a remarkably high erosion rate of 19.87 m year -1 and accretion of 16.91 m year -1 during a long-term scale (1990-2020). The average erosion and accretion rates were 2.25 m year -1 and 4.67 m year -1 , respectively, during the past three decades (1990-2020). The short-term analysis suggests that the highest mean erosion of 4.37 m year -1 occurred during 2005-2011, mainly due to cyclonic storms, reduction in sediment discharge, and lunar eclipse, which induced tide with very high amplitude in August 2008. Overall, the annual scale analysis of tidal inlet shows a shifting trend towards the northward side even after the artificial opening of an inlet in 2000. It can be ascribed mainly to the prevalent direction of longshore drift along this coast. This study observed that the landfall of cyclones significantly affects the spit morphodynamics and opening of the tidal inlet, which defines the inflow of the seawater into the lagoon and further substantial impacts on the ecological ramification. The current study's methodology can be extended to comprehend the response of long- to short-term changes of the tidal inlet, shoreline, and spit morphodynamics on the ecological ramification of coastal lagoons worldwide along with impacts of sudden-onset events caused by cyclonic landfall., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)