Net primary productivity and species diversity of herbaceous vegetation in banj-oak (Quercus leucotrichophora A. Camus) forest in Kumaun Himalaya, India     

Mukesh JOSHI  Y.S.RAWAT 《山地科学学报》2011,8(6):787-793

Net primary productivity and species diversity of herbaceous vegetation of banj-oak (Quercus leucotrichophora A.Camus) forest in Kumaun Himalaya,India were analyzed.Across different growth forms (tall forbs,short forbs,cushion and spreading forbs,grasses),short forbs were most dominant component during rainy season (IVI=152) and winter season (IVI=167) and grasses during the winter season (IVI=148).Maximum above-ground production occurred during rainy season (132.5 g m-2) and minimum during winter season (2.8 g m-2).Below-ground production was maximum (85.9 g m-2) during winter season and minimum (14.9 g m-2) during summer season.Annual net shoot production was 150 g m-2 and below-ground production was 138 g m-2.Of the total input 61 % was channeled to above-ground parts and 39% to below-ground parts.  相似文献   

Morphotectonic Features and Fault Propagation Folding of Bhuban Hills,NE India Using Satellite Image and DEM     

J. D. Das  Yazdana Shujat  A. K. Saraf  V. Rawat  K. Sharma 《Journal of the Indian Society of Remote Sensing》2011,39(1):73-81

Present topography of Bhuban Hills, lying in the Indo-Burman frontal fold belt of Northeastern part of India, is an aberration from a normal anticlinal morphology and exhibits several transverse and longitudinal fault affected segments resulting into distinct morphotectonic units. Six different morphotectonic units could be delineated along N-S stretch of the hill ridge. The western side of the northern most part of the hill ridge forms steep escarpment as this portion has been affected by the longitudinal faulting representing a case of fault propagation folding. The northernmost segment comprising three morphotectonic units (MU1 to MU3) is unique in the sense that this part exhibits effect of both the longitudinal and transverse faulting, uplifted narrow ridge with downthrown eastern side (MU2). Northern part of the Bhuban Hills has become curved westward due to the right lateral movement along the transverse fault TF1. The fifth morphotectonic unit (MU5) has undergone subsidence whereas, the sixth unit (MU6) exhibit bulging effect as this part experienced differential fault movements. Stream profiles, longitudinal and transverse topographic profiles extracted from contour map and Digital Elevation Model corroborated with the topographical anomalies developed over the Bhuban Hills.  相似文献   

3rd World Petroleum Council and Petrotech Youth Forum     

Suman Sarkar 《Journal of the Geological Society of India》2011,77(2):201

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Determination of in-situ stress direction from cleat orientation mapping for coal bed methane exploration in south-eastern part of Jharia coalfield, India     

Suman Paul Rima Chatterjee 《International Journal of Coal Geology》2011,87(2):87-96

Accurate prediction of in-situ stress directions plays a key role in any Coal Bed Methane (CBM) exploration and exploitation project in order to estimate the production potential of the CBM reservoirs. Permeability is one of the most important factors for determination of CBM productivity. The coal seams in Jharia coalfield generally show low permeability in the range of 0.5 md to 3 md. To estimate the in-situ stress direction in the study area, an attempt has been made to undertake the cleat orientation mapping of four regional coal seams of two underground coal mines located at south-eastern part of Jharia coalfield, India. Cleat orientation mapping is critical to determine the maximum principal compressive horizontal stress (S_H) direction for CBM exploration and exploitation, which in turn controls the direction of maximum gas or water flow though coal beds. From the field study it is found that the average face and butt cleat azimuths are towards N15°W and N75°E respectively. Average permeability of the four above-mentioned major coal seams has been calculated from well logs of nine CBM wells distributing over an area of 7.5 km², adjacent to the underground mines. The cleat orientations are congruous with the regional lineament pattern and fits well with the average permeability contour map of the study area to infer the orientation of in-situ maximum horizontal stress. Goodness of fit for the exponential regressions between vertical stress and permeability for individual coal seams varies between 0.6 and 0.84. The cleat orientation is further validated from the previous fracture analysis using FMI well log in Parbatpur area located southern part of the Jharia coalfield. The major coal seams under the study area exhibit directional permeability, with the maximum permeability, oriented parallel to the direction of face cleat orientation.  相似文献   

Monitoring of Microbiological Attributes of Soil and Groundwater Exposed to Metal Industrial Effluents     

Monica Rawat  Jaiprakash N. Rai 《洁净——土壤、空气、水》2013,41(11):1108-1115

The present paper evaluates the temporal and spatial impact of heavy metal containing (Cr, Zn, Cu, Ni, Cd and Fe) effluents of brass, electroplating and tannery industries on chemical and microbiological characteristics of affected soil and groundwater. Therefore, samples were drawn from three sites, S₁, S₂ and S₃, with a longitudinally distant from effluent drain of 20, 200 and 700 m, respectively. In general, the metals concentration exceeded the standard limits not only in the discharged effluents but also in the soil and groundwater. The significant reduction of microbial biomass C and N, soil respiration and microbial coefficient with increasing metal content from S₃ to S₁ was recorded, the effect being more pronounced in summer. However, the C_mic/N_mic ratio decreased whilst the metabolic quotient ($q_{{\rm CO}_{{\rm 2}} } $ ) increased with increasing metal concentration in soil. The content of Zn (11.5 mg/L) and Bacillus sp. was at maximum in groundwater of brass and electroplating industry site, whereas that of tannery site contained maximum Cr (2.34 mg/L) and Enterobacter sp. The toxic metals adversely polluted the groundwater which made it to harbours Escherichia coli beyond the prescribed limit. To check the soil and groundwater pollution, eco‐friendly measures involving improved effluent treatment technology and site‐specific application of treated effluent are recommended.  相似文献   

Geophysical Characterization of the Salna Sinking Zone, Garhwal Himalaya, India     

Rambhatla G. Sastry  Suman K. Mondal 《Surveys in Geophysics》2013,34(1):89-119

Infrastructure and communication facilities are repeatedly affected by ground deformation in Gharwal Himalaya, India; for effective remediation measures, a thorough understanding of the real reasons for these movements is needed. In this regard, we undertook an integrated geophysical and geotechnical study of the Salna sinking zone close to the Main Central Thrust in Garhwal Himalaya. Our geophysical data include eight combined electrical resistivity tomography (ERT) and induced polarization imaging (IPI) profiles spanning 144–600 m, with 3–10 m electrode separation in the Wenner–Schlumberger configuration, and five micro-gravity profiles with 10–30 m station spacing covering the study region. The ERT sections clearly outline the heterogeneity in the subsurface lithology. Further, the ERT, IPI, and shaliness (shaleyness) sections infer the absence of clayey horizons and slip surfaces at depth. However, the Bouguer gravity analysis has revealed the existence of several faults in the subsurface, much beyond the reach of the majority of ERT sections. These inferred vertical to subvertical faults run parallel to the existing major lineaments and tectonic elements of the study region. The crisscross network of inferred faults has divided the entire study region into several blocks in the subsurface. Our studies stress that the sinking of the Salna village area is presently taking place along these inferred vertical to subvertical faults. The Chamoli earthquake in March 1999 probably triggered seismically induced ground movements in this region. The absence of few gravity-inferred faults in shallow ERT sections may hint at blind faults, which could serve as future source(s) for geohazards in the study region. Soil samples at two sites of study region were studied in a geotechnical laboratory. These, along with stability studies along four slope sections, have indicated the critical state of the study region. Thus, our integrated studies emphasize the crucial role of micro-gravity in finding fine subsurface structure at deeper depth level; supported by ERT and IPI at shallow depth intervals, they can satisfactorily explain the Salna sinking zone close to Lesser Himalaya. The geotechnical studies also lend support to these findings. These integrated studies have yielded a better understanding of the mass-wasting mechanism for the study region.  相似文献   

Studies on the shift in the frequency of the first Schumann resonance mode during a solar proton event     

S.S. De  B.K. De  B. Bandyopadhyay  Suman Paul  D.K. Haldar  S. Barui 《Journal of Atmospheric and Solar》2010,72(11-12):829-836

The variation of the first Schumann resonance (SR) frequency spectra observed from the recorded data over Kolkata (22.56°N, 88.5°E) during a solar proton event (SPE) on July 14, 2000 has been presented. It shows increase in frequency during X-ray bursts and decrease during the period of occurrence of an SPE. The results from some other locations for the same event are also reported. The severe X-ray bursts recorded just before the proton event exhibit enhancement in frequency of the first mode due to enhancement of ionization in the D-region of the ionosphere. Some attempts are made to explain the observed variation during solar proton events in terms of the perturbations within the Earth–ionosphere waveguide on the basis of two-layer-model.  相似文献   

Triggered star formation and evolution of T-Tauri stars in and around bright-rimmed clouds     

Neelam Chauhan  A. K. Pandey  K. Ogura  D. K. Ojha  B. C. Bhatt  S. K. Ghosh  P. S. Rawat 《Monthly notices of the Royal Astronomical Society》2009,396(2):964-983

The aim of this paper is to quantitatively testify the ' small-scale sequential star formation ' hypothesis in and around bright-rimmed clouds (BRCs). As a continuation of the recent attempt by Ogura et al., we have carried out   BVI_c   photometry of four more BRC aggregates along with deeper re-observations of two previously observed BRCs. Again, quantitative age gradients are found in almost all the BRCs studied in the present work. Archival Spitzer /Infrared Array Camera data also support this result. The global distribution of near-infrared excess stars in each H  ii region studied here clearly shows evidence that a series of radiation-driven implosion processes proceeded in the past from near the central O star(s) towards the peripheries of the H  ii region. We found that in general weak-line T-Tauri stars (WTTSs) are somewhat older than classical T-Tauri stars (CTTSs). Also the fraction of CTTSs among the T-Tauri stars (TTSs) associated with the BRCs is found to decrease with age. These facts are in accordance with the recent conclusion by Bertout, Siess & Cabrit that CTTSs evolve into WTTSs. It seems that in general the equivalent width of Hα emission in TTSs associated with the BRCs decreases with age. The mass function (MF) of the aggregates associated with the BRCs of the morphological type 'A' seems to follow that found in young open clusters, whereas 'B/C'-type BRCs show significantly steeper MF.  相似文献   

A unified earthquake catalogue for South Asia covering the period 1900–2014     

Nath  Sankar Kumar  Mandal  Suman  Das Adhikari  Manik  Maiti  Soumya Kanti 《Natural Hazards》2017,85(3):1787-1810

Seismicity analysis is very much pertinent for Indian subcontinent and its adjoining region which is seismically active including many great earthquakes associated with collision and subduction tectonics in the northern, north-eastern part of the subcontinent and in the Andaman and Nicobar Island. An earthquake catalogue has been generated for South Asia covering the period 1900–2014 by compiling the records of earthquake occurrences from International Seismological Center, Global Centroid Moment Tensor (GCMT), US Geological Survey, India Meteorological Department and published literature. The uniform magnitude scaling in moment magnitude M _W,GCMT is achieved through connecting relationships between different magnitude types. These relationships are derived by orthogonal standard regression analysis on available data pairs. The derived relationships have been compared with the existing equations already reported by others. The catalogue is subsequently subjected to a seismicity declustering algorithm to identify the foreshocks, main-shocks and aftershocks. The catalogue thus compiled is envisaged to be a useful resource for seismotectonic and seismic hazard studies in the region.

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Morphotectonic analysis of alluvial fan dynamics: comparative study in spatio-temporal scale of Himalayan foothill,India     

Suman Ayaz  Mery Biswas  Md Kutubuddin Dhali 《Arabian Journal of Geosciences》2018,11(2):41

Alluvial fan is a depositional fluvial landform that is characterised by sediment flow and hydrological processes and is also controlled by tectonic activity. These extraordinary features have always attracted researchers since the past as they preserve the past records, but now, this study is focused on the formation meso-level fans with its spatio-temporal dynamic nature. These tributaries have formed secondary alluvial fans at their debouching points. The dynamics of the fans are controlled by the hydrological responses and tectonic base and also by the sedimentation processes. The origin of these tributaries and their respective fans are related to the last stage of Himalayan uplift. This is the region of Himalayan foreland basin which contains the main frontal thrust and makes the region tectonically very active. The region is drained by many large rivers and their numerous tributaries. The active tectonism, the configuration of the basin and also the deposition of the sediments carried by these rivers have formed alluvial fans where the channel debouches into the widened valley. In the present study, the meso-level alluvial fans formed by River Gish and the Rivers Neora and Murti have been studied. Both these fans are present in the piedmont region of the Himalayas, but they deliver different characteristics, and the nature of their deposition is also different. This is mainly because of the influence of the minor faults in the region which control the channel pattern and also have a great influence in the sediment delivery to the downstream section of the channels. Thus, in order to understand the influence of tectonics in the dynamics of these fans, some morphotectonic parameters have been taken into consideration. These include mountain front sinuosity index, valley floor width-to-depth ratio, and tectonic tilt. The calculated hypsometric integral also depicts that the two fans are at different stages of development.  相似文献