Slope stability assessment and design of remedial measures for Tungnath Temple at Uttarakhand,India: a case study     

Samanta  M.  Punetha  P.  Sarkar  S.  Dwivedi  A.  Sharma  M. 《Natural Hazards》2019,96(1):225-246

Natural Hazards - The present paper assesses the slope stability of the Tungnath Temple at Rudraprayag District, in the Indian state of Uttarakhand, and suggests the remedial measures. The...  相似文献   

Arsenic distribution along different hydrogeomorphic zones in parts of the Brahmaputra River Valley,Assam (India)     

Runti Choudhury  Chandan Mahanta  Swati Verma  Abhijit Mukherjee 《Hydrogeology Journal》2017,25(4):1153-1163

The spatial distribution of arsenic (As) concentrations along three classified hydrogeomorphological zones in the Brahmaputra River Valley in Assam (India) have been investigated: zone I, comprising the piedmont and alluvial fans; zone II, comprising the runoff areas; and zone III, comprising the discharge zones. Groundwater (150 samples) from shallow hand-pumped and public water supply wells (2–60 m in depth) was analysed for chemical composition to examine the geochemical processes controlling As mobilization. As concentrations up to 0.134 mg/L were recorded, with concentrations below the World Health Organization and the Bureau of Indian Standards drinking-water limits of 0.01 mg/L being found mainly in the proximal recharge areas. Eh and other redox indicators (i.e., dissolved oxygen, Fe, Mn and As) indicate that, except for samples taken in the recharge zone, groundwater is reducing and exhibits a systematic decrease in redox conditions along the runoff and discharge zones. Hydrogeochemical evaluation indicated that zone I, located along the proximal recharge areas, is characterized by low As concentration, while zones II and III are areas with high and moderate concentrations, respectively. Systematic changes in As concentrations along the three zones support the view that areas of active recharge with high hydraulic gradient are potential areas hosting low-As aquifers.  相似文献   

Assessment of impervious surface growth in urban environment through remote sensing estimates     

Anindita Sarkar Chaudhuri  Prafull Singh  S. C. Rai 《Environmental Earth Sciences》2017,76(15):541

The fast growth in population and expansion of urban built area has led to the transformation of the natural landscape into impervious surfaces. Remote sensing-based estimate of impervious surface area (ISA) has emerged as an important indicator for the assessment of water resources depletion in urban areas and developed a correlation between land-use change and their potential impact on urban hydrology. In the present work, a remote sensing-based Impervious Surface Area (ISA) was carried out for New Okhla Industrial Development Authority (NOIDA) city, one of the fastest growing cities in National Capital Region (NCR) of India. The impervious surface area (ISA) of NOIDA was calculated for the years 2001, 2007 and 2014 using multi-temporal LANDSAT thermal data by applying linear spectral mixing analysis (LSMA) techniques to monitor the growth rate of impervious surface. The results observed by analysis of multi-temporal satellite images show an extreme temporal change in the growth of ISA in the city. The ISA observed for the year 2001 is 28 sq.km; in 2007, its increase was 48 sq.km and was 132 in 2014. The results were observed from this work through the use of satellite data which is very important for water resource management, planning and prediction of ISA impact on hydrology.  相似文献   

Facies analysis of Pleistocene limestones from Neil West Coast Formation,Neil Island,Ritchie’s archipelago of South Andaman,India     

Arindam Chakraborty  Amit K. Ghosh  Abhijit Mazumder 《Journal of the Geological Society of India》2017,90(4):428-436

Petrographic thin section analysis of the samples collected from the type section of Neil West Coast Formation, situated in the west coast of Neil Island yielded moderately preserved coralline red algae, benthic and planktic foraminifers, coral fragments, echinoid spines and gastropod shells. The coralline red algae are represented by both non-geniculate and geniculate forms. The non-geniculate forms belong to melobesids, lithophylloids and mastophoroides. The geniculate forms are represented by species of Amphiroa, Corallina, and Jania. However, the diversity and abundance of coralline algal forms are less in comparison to the benthic foraminifers those are represented by Amphistegina, Neorotalia, Ammonia, Elphidium, Operculina, Assilina, Amphisorus and texularids. Planktic foraminifers like Globigerinoides and other biogenic components viz., gastropod shells, echinoid spines and coral fragments are also common. A foraminiferal-algal grainstone facies has been recognized as observed in the field as well as in thin section analysis. The overall assemblage of the biogenic components and facies analysis indicate intertidal to near shore environment of deposition with high energy condition and increased hydrodynamic activity.  相似文献   

Qualitative stability assessment of cut slopes along the National Highway-05 around Jhakri area,Himachal Pradesh,India     

Jagadish Kundu  Kripamoy Sarkar  Ashutosh Tripathy  T N Singh 《Journal of Earth System Science》2017,126(8):112

Several deformation phases in tectonically active Himalayas have rendered the rock masses very complex in terms of structure, lithology and degree of metamorphism. Again, anthropogenic activities such as roads, tunnels and other civil engineering constructions have led to a state of disequilibrium which in many cases, results in failure of rock masses. National Highway-05 around Jhakri area in India is a major connecting route to the China border in the hilly terrains of the state Himachal Pradesh. It cuts through the Himalayan rocks and has a hazardous history of landslides destroying human lives and interrupting communication very frequently. As a contribution towards the mitigation process, a study has been carried out along the highway to analyse kinematic stability and qualitative estimation of rock mass condition through rock mass classification systems. The kinematic analysis shows that the rock slopes are prone to planar and wedge failure. Rock mass rating for most of the locations lies between 7 and 34, representing a poor rock mass quality (Class IV), whereas slope mass rating is more disperse and ranges from 11 to 52 for most of the slopes (Class III, IV and V).  相似文献   

Transient heating of the upper atmosphere by auroral electric field     

S. S. De  B. K. Sarkar  B. Ghosh  Manasi Mal  S. K. Adhikari 《Astrophysics and Space Science》1991,180(2):201-209

Magnetohydrodynamic formulation has been used to deduce the velocity distribution of the upper atmospheric movement caused by the auroral electric field at the thermospheric height. The expressions for Joule heating and viscous heating are obtained. Numerical analysis has been made to estimate their magnitudes as well as the rate of their variations with time. The results are presented graphically.  相似文献   

The appropriate dyadic applicable to the lower region of the ionospheric plasma     

S. S. De  S. Bandyopadhyay  S. K. Dubey  B. K. Sarkar  A. C. Sen  S. K. Adhikari 《Earth, Moon, and Planets》1992,56(1):1-6

An expression for the susceptibility dyadic appropriate to the lower regions of the atmospheric plasma is derived using Maxwell's field equations and the equation of conservation of momentum. The contributions due to viscous effect and convection current density are incorporated in the physical processes within the stated medium. Utilizing the approximation of linearized equations, second order coupled wave equations have been derived through the dyadic.  相似文献   

Spectrum of average flux of the S-component of solar radio emission     

M. K. Das Gupta  S. K. Sarkar 《Solar physics》1971,18(2):276-283

Spectrum of average flux of the S-component of solar radio emission observed during the peak phase of the present solar cycle has been determined statistically. Daily values of the mean solar flux at 606, 1415, 2695, 4995 and 8800 MHz observed at the Sagamore Hill Solar Radio Observatory have been examined. The superposed epoch method (Chree analysis) has been used for determining the true nature of the S-component at all these frequencies. Spectrum has been obtained after elimination of the basic components at the respective frequencies. The important results obtained from the present statistical investigation are: (1) the basic component increases with frequency, (2) the S-component shows a maximum at 4995 MHz (6 cm), (3) the spectrum is independent of the phase of the 27-day cycle and (4) S-components at all the frequencies have slopes which are both more uniform and higher in the ascending phase than those in the descending phase of the 27-day cycle. In the descending phase slopes increase with frequency.  相似文献   

Growth rate and life span of Eocene/Oligocene Nummulites tests: inferences from Sr/Ca ratio     

S. Sarangi  A. Sarkar  M. M. Sarin  S. K. Bhattacharya  M. Ebihara  & A. K. Ray 《地学学报》2001,13(4):264-269

The problem of growth rate and life span of Nummulites foraminifers, attaining giant sizes during the Eocene, has been addressed by analysing their Sr/Ca ratio across the Eocene/Oligocene Boundary (EOB) of Kutch, western India. The Eocene ratio (˜ 1) rapidly decreases during the Oligocene (˜ 0.5) and is coincident with the extinction of most of the Eocene Nummulites species, a rapid enrichment of δ¹⁸O and decrease in both test size and species diversity across the boundary. The high Sr/Ca ratio in Eocene foraminifers can be explained by their rapid growth under a favourable climatic condition. The climatic deterioration (e.g. δ¹⁸O cooling) across the boundary and during the early Oligocene possibly forced the Nummulites to adopt a slower growth rate (and stunted growth). The rapid growth of the Eocene Nummulites indicates that the giant sizes of these protists need not necessarily involve a large life span.  相似文献   

Non-linear r.f. heating of ionospheric plasma     

S. S. De  S. K. Adhikari  B. K. Sarkar 《Earth, Moon, and Planets》1988,41(3):217-222

The non-linear heating of electrons in the ionospheric plasma due to high-power radio wave propagation has been investigated through an integro-differential equation derived from Boltzmann velocity-moment equations. Various processes appropriate to the situation under study are taken into account. The numerical solution of the derived equation is presented graphically.Department of Applied Mathematics, University of Calcutta, India.  相似文献