Impact of the Trans-Himalayan Landslide Lake Outburst Flood (LLOF) in the Satluj catchment, Himachal Pradesh, India     

Vikram Gupta  M. P. Sah 《Natural Hazards》2008,45(3):379-390

Landslide Lake Outburst Floods (LLOFs) are common in the Himalayan river basins. These are caused by breaching of lakes created by landslides. The active and palaeo-landslide mapping along the Satluj and Spiti Rivers indicate that these rivers were blocked and breached at many places during the Quaternary period. In the present article, we document LLOFs during 2000 and 2005 caused by the breaching of landslide lakes created in the Trans-Himalayan region along the Satluj River and Paree Chu (stream), respectively, both in the Tibetan region of China and its impact on the channel and infrastructure in the Kinnaur district of Himachal Pradesh, India. It has been observed that the loss of life and property due to these LLOFs is directly related to the disposition of the Quaternary materials and the different morphological zones observed in the area.  相似文献   

An experimental study of dissolution kinetics of Calcite, Dolomite, Leucogranite and Gneiss in buffered solutions at temperature 25 and 5°C   总被引：1，自引：0，他引：1  

S. K. Yadav  G. J. Chakrapani  M. K. Gupta 《Environmental Geology》2008,53(8):1683-1694

Laboratory experiments were carried out continuously for 30–35 days at 25 and 5°C in three different buffer solutions of pH 4.0, 2.2 and 8.4 to calculate dissolution rates of two minerals, calcite (CC) and dolomite (DM) and two rocks, leucogranite (LG) and gneiss (GN) from the Himalayan range. Calculated rates in terms of release of targeted elements versus time (Ca for CC; Mg for DM; Si for LG and GN) demonstrate direct correlation with temperature. Dissolution rates are higher at 25°C compared to 5°C. CC and DM were experimented only at pH 8.4 and results show that both undergo congruent dissolution with CC dissolving ∼5 times faster than DM. Ca and Mg exhibit average apparent activation energies (E _a) of 13.98 and 9.98 kcal mol⁻¹ respectively at pH 8.4 which reflects greater sensitivity of CC dissolution than DM dissolution towards an increase in temperature. Scanning Electron Microscope attached with Energy Dispersive X-Ray Analyser (SEM-EDX) data indicates that dissolution is controlled primarily by surface-reaction processes, with dislocation sites contributing maximum to the dissolution. As compared to CC and DM dissolution, LG and GN undergo relatively slower incongruent dissolution with precipitation of some secondary minerals as revealed from X-ray diffractometer (XRD) results. Rates of dissolution of LG is maximum at pH 2.2, moderate at pH 8.4 and least at pH 4.0, whereas GN shows maximum dissolution at pH 2.2, moderate at pH 4.0 and least at pH 8.4. A comparison in dissolution behavior of LG and GN at experimental conditions reveals that increase in Si-release rate in the temperature range between 5 and 25°C is maximum at pH 8.4 (∼3.4–4.5 times), moderate at pH 4.0 (∼3–1.8 times) and least at pH 2.2 (∼1.0–1.5 times). Within the experimental temperature range, calculated values of E _a for Si release during LG and GN dissolution advocates positive correlation with pH. A substantial decrease in initial values of Brunauer–Emmett–Teller (BET) surface area of DM, LG, and GN has been encountered at the end of the experiment, except for CC for which an increase is observed. The study clearly demonstrates the dissolution behavior of pure minerals and rocks under controlled conditions. The dissolution rates assume enormous significance for the release of trace elements from rocks/minerals to the reacting water.  相似文献   

Theoretical Evaluation of Modified Wenner Array for Shallow Resistivity Exploration   总被引：1，自引：0，他引：1  

Vikas C. Goyal  Sri Niwas  Pravin K. Gupta 《Ground water》1991,29(4):582-586

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Toroidal oscillations of a transradially isotropic elastic sphere     

Alka Gupta  Sarva Jit Singh 《Journal of Earth System Science》1990,99(3):383-391

In order to consider the effect of anisotropy on the periods of the oscillations of the Earth, the problem of toroidal oscillations of a transradially isotropic elastic sphere is considered. At each point, the medium is assumed to be transversely isotropic about the radius through the point. The roots of the frequency equation are obtained for different values of the anisotropy parameter α. It is found that, for large order oscillations, the percentage change in the frequency of the toroidal oscillations on account of the anisotropy is nearly equal to |α-1| × 100.  相似文献   

Preliminary phase equilibria of the nepheline-diopside system under variable pressures (up to 28 kb) and temperatures     

Puniti Singh  Rajeev Chopra  Alok K Gupta 《Journal of Earth System Science》1990,99(1):49-55

The nepheline-diopside join defines the ultra-alkaline portion of the basalt tetrahedron and the bulk composition of nephelinitic rocks lie in this join. Schairer and others established that under atmospheric pressure, the join cuts through the primary phase volumes of olivine_ss, carnegieite_ss and nepheline_ss. Melilite coexists with nepheline_ss, olivine_ss and diopside_ss below 1160±10°C and olivine reacts out at low temperature. Experimental studies on seven compositions show the presence of a pseudoeutectic at Ne₇₀Di₃₀ and 1420°C, where diopside_ss, nepheline_ss and liquid are in equilibrium. Olivine and melilite do not appear in the system and the assemblage below 1225±20°C is diopside_ss+nepheline_ss.  相似文献   

Ca II K line profile of the truly quiet Sun     

K. R. Sivaraman  S. S. Gupta  R. Kariyappa 《Solar physics》1996,163(1):93-97

While evaluating the chromospheric variability (solar cycle related or any other) using the Ca II K line (3933.684 Å) as an indicator, an essential prerequisite is the knowledge of the profile of a truly quiet Sun in the integrated light. Such a profile can serve as a bench mark over which enhancements can be measured, particularly when modelling variability. This paper describes how such a K-line profile has been derived for the quiet Sun using disc-integrated light.  相似文献   

Enhanced reservoir-induced earthquakes in Koyna region, India, during 1993–95     

H. K. Gupta  B. K. Rastogi  R. K. Chadha  P. Mandal  C. S. P. Sarma 《Journal of Seismology》1997,1(1):47-53

Reservoir induced earthquakes began to occur in the vicinity of Shivajisagar Lake formed by Koyna Dam in Maharashtra state, western India, soon after its filling started in 1962. Induced earthquakes have continued to occur for the past 34 years in the vicinity of this reservoir, and so far a total of 10 earthquakes of M 5.0, over 100 of M 4 and about 100,000 of M 0.0 have occurred. Every year, following the rainy season, the water level in the reservoir rises and induced earthquakes occur. Seismic activity during 1967–68 was most intense when globally, the largest reservoir induced earthquake occurred on 10 December, 1967. Other years of intense seismic activity are 1973 and 1980. During 1986 another reservoir, Warna, some 20 km south of Koyna, began to be filled. The recent burst of seismic activity in Koyna-Warna region began in August, 1993, and was monitored with a close network of digital and analog seismographs. During August, 1993–December, 1995, 1,272 shocks of magnitude 2 were located, including two earthquakes of M 5.0 and M 5.4 on 8 December, 1993 and 1 February, 1994, respectively. Two parallel epicentral trends in NNE-SSW direction, one passing through Koyna and the other through Warna reservoir are delineated. The 1993 increase in seismicity has followed a loading of 44.15 m in Warna reservoir during 11 June 11, 1993 through August 4, 1993, with a maximum rate of filling being 16 m/week. The larger shocks have been found to be preceded by a precursory nucleation process.  相似文献   

Empirical assessment of adaptation to climate change impacts of mountain households: development and application of an Adaptation Capability Index     

Rajiv Pandey  Nandini Maithani  Roberta Aretano  Giovanni Zurlini  Kelli M. Archie  Ajay K. Gupta  Vishnu Prasad Pandey 《山地科学学报》2016,13(8):1503-1514

The present study proposes an index to assess the potential for adaptation to climate change for households in the mountainous regions. The index provides a realistic approach to recognize social and natural factors which contribute to successful adaptation and addresses several household functions, such as social networking, livelihood strategy, adjustment strategies, resource availability and accessibility. The proposed Adaptation Capability Index (ACI) is analytically defined, mathematically formulated and field tested on mountainous households in urban and semi-urban regions of the Uttarakhand Himalaya in India. To gather data on the topic relevant to the ACI, a household scale questionnaire was developed and administered to 120 heads of households through face-to-face interviews. The results highlight higher adaptive capability of urban households and low adaptation capacity of rural households due to poor farm productivity, low accessibility and availability of resources and technological input. Future programs and policies must include and implement regulations to remedy attributive factors responsible for higher adaptation. This paper may be applicable to other mountainous regions and may provide insights for effective adaptation strategies to climate change.  相似文献   

Advanced oxidation of catechol in reverse osmosis concentrate generated in leather wastewater by Cu–graphite electrode     

P. Maharaja  R. Boopathy  S. Karthikeyan  M. Mahesh  A. S. Komal  V. K. Gupta  G. Sekaran 《International Journal of Environmental Science and Technology》2016,13(9):2143-2152

Reverse osmosis (RO) concentrate generated from tannery was treated by advanced electrochemical oxidation using graphite electrodes. Catechol was selected as model organic pollutant in the RO concentrate. The influence of applied current density, catechol concentration, pH, temperature and inner electrode space of electrodes was investigated in electrochemical oxidation system. The optimized conditions were found to be current density (j), 100 mA/cm²; electrolysis time (t _eco), 60 min; pH, 7.0; and temperature, 25 °C at an inner electrode space, 2 cm. The average mass transport coefficient for the removal of catechol as COD was found to be 3.0 × 10^?5 m/s at optimum conditions. Faradic efficiency and specific energy consumption were also calculated for the applied current density. Further, the treatment of catechol was confirmed through Fourier transform infrared spectroscopy. Theoretical evaluation of current density suggested that the removal of catechol was controlled when supplied at above limiting applied current densities and mass transport controlled at lower of limiting current densities.  相似文献   

Support vector machines and generalized linear models for quantifying soil dehydrogenase activity in agro-forestry system of mid altitude central Himalaya     

Prashant K. Srivastava  Aradhana Yaduvanshi  Sudhir Kumar Singh  Tanvir Islam  Manika Gupta 《Environmental Earth Sciences》2016,75(4):299

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