Assessing coastal landscape vulnerability using geospatial techniques along Vizianagaram–Srikakulam coast of Andhra Pradesh,India

Vizianagaram–Srikakulam coastal shoreline consisting of beaches, mangrove swamps, tidal channel and mudflats is one of the vulnerable coasts in Andhra Pradesh, India. Five site-specific parameters, namely rate of geomorphology, coastal elevation, coastal slope, shoreline change and mean significant wave height, were chosen for constructing coastal vulnerability index and assessing coastal landscape vulnerability. The findings revealed a shift of 2.5 km in shoreline towards the land surface because of constant erosion and that of 1.82 km towards the sea due to accretion during 1997–2017. The rate of high erosion was found in zones IV and V, and high accretion was found in zones II and III. Coastal vulnerability index analysis revealed constant erosion along shoreline and sea level rise in the study area. Most of the coast in zone V has recorded very high vulnerability due to erosion, high slope, significant wave height and sea level rise. Erosion and accretion, significant wave height, sea level rise and slope are attributed to high vulnerability in zones III and IV. Zone II recorded moderate vulnerability. Relatively lower slope, mean sea wave height and sea level rise have made this zone moderately vulnerable. Very low vulnerability was found in zone I, and low vulnerability was recorded in zone II. Accretion, low slope and low sea level rise were found to be causative factors of lower vulnerability. Thus, zones III, IV and V should be accorded higher priorities for coastal management. The findings can be helpful in coastal land planning and management and preparing emergency plans of the coastal ecosystems.     

Expansion of a glacial lake,Tsho Chubda,Chamkhar Chu Basin,Hindukush Himalaya,Bhutan

Natural Hazards - A wide range of methods for detection of glacial lakes and their expansions using multi-temporal remote sensing images have been employed in the past. This paper presents a...     

Potential environmental pollution hazards by coal based power plant at Jhansi (UP) India

Coal, a fossil fuel, is the largest source of energy for the generation of electricity in India. In order to study the potential environmental hazards by coal based power plants, particulate matters were collected using Stack Monitoring Kit and gaseous pollutants by Automatic Flue Gas Analyzer. The morphological and chemical properties, mineralogical composition and particle size distributions have been determined by SEM–EDX, XRD and CILAS. The data revealed the presence of particulate matters, SO₂, NOx in the range of 236–315, 162–238, 173–222 mg/Nm³ respectively. The emission of CO₂ was in the range of 43,004–60,115 Nm³/h with an average of 52,830 Nm³/h. Among the elements, Fe > Mn > Al > Zn > B > Ni > Cr > Cu were present in substantially higher proportion than Pb > Mo > Cd > Se > As > Hg. It was found that most of the elements were concentrated on fly ash surface rather than coal, bottom ash and pond ash. This variation may be attributed to the fineness of fly ash particles with large surface ratio to mass. Mineralogical studies of coal and fly ash by X-ray diffraction revealed the presence of mullite, quartz, cristobalite and maghemite. Presence of mullite and quartz found in fly ash indicate the conversion of complex minerals to mullite and quartz at high temperature. Transfer Coefficient was calculated to determine the ratio of the enrichment of trace elements in fly or bottom ash with respect to coal and pond ash.     

Sr isotopic signature of the Ganga Alluvial Plain and its implication to Sr flux of the Ganga River System

The influx of Sr responsible for increase in marine Sr has been attributed to rise of Himalaya and weathering of the Himalayan rocks. The rivers draining Himalaya to the ocean by the northern part of the Indian sub-continent comprising the Ganga Alluvial Plain (GAP) along with Central parts of the Himalaya and the northern part of the Indian Craton are held responsible for the transformation of Sr isotopic signature. The GAP is basically formed by the Himalayan-derived sediments and serves as transient zone between the source (Himalaya) and the sink (Bay of Bengal). The Gomati River, an important alluvial tributary of the Ganga River, draining nearly 30,500 km² area of GAP is the only river which is originating from the GAP. The river recycles the Himalayan-derived sediments and transport its weathering products into the Ganga River and finally to Bay of Bengal. 11 water samples were collected from the Gomati River and its intrabasinal lakes for measurement of Sr isotopic composition. Sr concentration of Gomati River water is about 335 μg/l, which is about five times higher than the world’s average of river water (70 μg/l) and nearly three times higher than the Ganga River water in the Himalaya (130 μg/l) The Sr isotopic ratios reported are also higher than global average runoff (0.7119) and to modern seawater (0.7092) values. Strong geochemical sediment–water interaction appearing on surface is responsible for the dissolved Sr isotopic ratios in the River water. Higher Sr isotopic rations found during post-monsoon than in pre-monsoon season indicate the importance of fluxes due to monsoonal erosion of the GAP into the Gomati River. Monsoon precipitation and its interaction with alluvium appear to be major vehicle for the addition of dissolved Sr load into the alluvial plain rivers. This study establishes that elevated ⁸⁷Sr/⁸⁶Sr ratios of the Gomati River are due to input of chemical weathering of alluvial material present in the Ganga Alluvial Plain.     

On the influence of spatial heterogeneity on an internal boundary layer at a short fetch

Surface layer meteorological data collected at a coastal site, at Vasco-Da-Gama (15°21′N, 73°51′E, 58.5m MSL) (13–18 July, 2002) with prevailing southwesterly surface winds are analyzed to study the characteristics of internal boundary layer at a short fetch using an instrumented tower (9 m). The spectral and turbulence characteristics of wind are compared with earlier measurements made at a comparatively homogeneous terrain and the standards available in literature. The study show the smaller eddies in the vertical velocity spectrum attains equilibrium with the underlying surface at a short fetch itself and follows spectral similarity. However, this is not followed by longitudinal and transverse velocity spectra under unstable as well as stable conditions.     

DEM Generation for Lunar Surface using Chandrayaan-1 TMC Triplet Data

Digital Elevation Model (DEM) is an important prerequisite for understanding the lunar surface. However, making accurate DEM is a very challenging task due to (a) lack of support of projection parameters in COTS packages (eg. PCI Geomatica), which are to be used in generation of Lunar DEM and (b) unavailability of Ground Control Points (GCPs). In the present study, DEM generation of lunar surface was attempted without GCPs using Rational Function (RF) model from Chandrayaan-1 TMC triplet images. In the study, a good correlation (of almost same order) is observed between Nadir-Fore (NF), Nadir - Aft (NA), Fore - Aft (FA) and Fore - Nadir - Aft (FNA) image pairs. The results suggest that DEM for lunar surface can be created without GCPs using RF model.     

Geochemical characterization of arsenic-affected alluvial aquifers of the Bengal Delta (West Bengal and Bangladesh) and Chianan Plains (SW Taiwan): Implications for human health

Major ion and trace element analyses were performed on groundwater samples collected from the Bengal Delta (Chakdaha municipality, West Bengal and Manikgonj town, Bangladesh) and Chianan Plains (SW Taiwan) to compare geochemical characteristics. Results showed that concentrations of Na, K, Mg, Cl and SO₄ were generally higher in Chianan Plain (CNP) groundwaters, while high Ca was observed in Bengal Delta Plain (BDP) groundwater. Measured As concentrations in groundwaters of BDP and CNP showed large variations, with mean As concentrations of 221 μg/L (range: 1.1-476 μg/L) in Chakdaha, 60 μg/L (range: 0.30-202 μg/L) in Manikgonj, and 208 μg/L (range: 1.3-575 μg/L) in CNP groundwater. The Fe-reduction mechanism was found to be the dominant geochemical process in releasing As from sediment to groundwater in Chakdaha, West Bengal, however the Mn-reduction process was dominant in groundwaters of Manikgonj, Bangladesh. In Chianan Plain groundwater, a combination of geochemical processes (e.g., bacterial Fe-reduction, mineral precipitation and dissolution reactions) controlled release of As. Fluorescence spectral patterns of the groundwater showed low relative fluorescence intensity (RFI) of dissolved humic substances in BDP groundwater (mean: 63 and 72 QSU, Chakdaha and Manikgonj, respectively), while high RFI was observed in CNP groundwater (mean: 393 QSU). The FT-IR spectra of the extracted humic acid fractions from sediments of Chianan Plain showed a stronger aliphatic band at 2850-3000 cm⁻¹ and a higher resolved fingerprint area (from 1700 to 900 cm⁻¹) compared with BDP sediments. The geochemical differences between the study areas may play a crucial role in the clinical manifestation of Blackfoot disease observed only in Chianan Plain, SW Taiwan.     

Simulation of peri-urban growth dynamics using weights of evidence approach

The study aims to simulate the peri-urban growth dynamics in a growing region of India using Weights of Evidence (WOE) based cellular automata model. The growth process was expressed as a function of four causative variables corresponding to which seven data layers were generated in a Geographic Information Systems environment. The model was calibrated for the period 2000–2005 using Kappa indices and fuzzy set theory based two way comparison method. The Kappa value was 0.7, while the value of K_location and K_histo were 0.81 and 0.93, respectively. The fuzzy similarity values increased for small to large neighbourhood sizes which showed that the model was able to simulate the contiguous and dense growth. However, for dispersed and isolated growth the model showed less accuracy. The model was validated for period 2005–2010 and revealed a Kappa value of 0.88, while value of K_location and K_histo were 0.91 and 0.96, respectively.     

Rock Mass Classification and Slope Stability Assessment of Road Cut Slopes in Garhwal Himalaya, India

There are many rock mass classification schemes which are frequently used for different purposes such as estimation of strength and deformability of rock masses, stability assessment of rock slopes, tunneling and underground mining operations etc. The rock mass classification includes some inputs obtained from intact rock and discontinuity properties which have major influence on assessment of engineering behaviour of rock mass. In the present study, detail measurements were employed on road cuts slope faces in Garhwal Himalayas to collect required data to be used for rock mass classification of Rock Mass Rating (RMR) and Geological Strength Index (GSI). The stability assessment of rock slopes were also done by using Slope Mass Rating. In addition the relation between RMR and GSI were also evaluated using 50 data pairs.     

Tectonics of the southern Asian Plate margin along the Karakoram Shear Zone: Constraints from field observations and U–Pb SHRIMP ages

New geological observations, recent published data and U–Pb SHRIMP zircon dating from the Karakoram Mountains along the Nubra and Shyok Rivers reveal that the initial subduction of the Tethyan oceanic lithosphere took place ~ 110 Ma beneath the Paleozoic–Mesozoic platform of the southern edge of the Asian Plate. This has produced the I-type plutons within the Karakoram Batholith Complex, well before the juxtaposition of the Asian Plate along the Karakoram Shear Zone. Within this shear zone, U–Pb zircon crystallisation ages of ~ 75 Ma from mylonitised granitoids and 68 Ma from undeformed Tirit granodiorite constrain the timing of suturing of the Karakoram terrain with the Trans-Himalaya between 75 and 68 Ma. Post-shearing leucogranite was episodically generated within frontal migmatised Karakoram Metamorphic Belt and emplaced between 20 and 13 Ma within the shear zone. Presence of a low resistivity zone as a possible indication of mid-crustal partial molten crust underneath the Higher Himalaya–Ladakh–Karakoram terrains manifests the impingement of the Indian Plate along the Main Himalayan Thrust at depth.

Physical continuity of the Baltoro granite belt into the Karakoram Batholith is established as well as the continuity of the Shyok suture as the Shiquanhe Suture Zone in western Tibet through the Chushul–Dungti sector. The Karakoram Shear Zone, therefore, displays a complex geological history of movements since ~ 75 Ma and plays a very significant role in the overall India–Asia convergence, rather than merely being a strike-slip fault for eastward extrusion of a segment of Asia in Tibet.