Hydrogeologic characteristics of groundwater aquifers in Kathmandu Valley,Nepal     

Vishnu Prasad Pandey  Futaba Kazama 《Environmental Earth Sciences》2011,62(8):1723-1732

This paper reviews, compiles and comprehensively analyzes spatial variations in hydrogeologic characteristics of shallow and deep groundwater aquifers in Kathmandu Valley. To estimate transmissivity (T) (and then hydraulic conductivity) as a function of specific capacity (SC), an empirical relationship between T and SC is developed for shallow and deep aquifer. The results show that T and SC are log linearly related by an equation T = 0.8857(SC)^1.1624 [R ² = 0.79] in shallow and T = 1.1402(SC)^1.0068 [R ² = 0.85] in deep aquifer. The estimated T ranges from 163 to 1,056 m²/day in shallow aquifer and 22.5 to 737 m²/day in deep aquifer. Finally, mapping of spatial distribution in hydrogeologic characteristics (thickness, T, hydraulic conductivity and storage coefficient) in shallow and deep aquifers are accomplished using ArcGIS9.2 and such maps would be useful in delineating potential areas for groundwater development and simulating groundwater flow in the aquifer system.  相似文献   

Bianchi type V universe with bulk viscous matter and time varying gravitational and cosmological constants     

Prashant Singh Baghel  Jagdish Prasad Singh 《天文和天体物理学研究(英文版)》2012,(11):1457-1466

We consider spatially homogeneous and anisotropic Bianchi type V space- time with a bulk viscous fluid source, and time varying gravitational constant G and cosmological term Λ. The coefficient of bulk viscosity ζ is assumed to be a simple linear function of the Hubble parameter H (i.e. ζ = ζ 0 + ζ 1 H , where ζ 0 and ζ 1 are constants). The Einstein field equations are solved explicitly by using a law of variation for the Hubble parameter, which yields a constant value of the deceleration parameter. Physical and kinematical parameters of the models are discussed. The models are found to be compatible with the results of astronomical observations.  相似文献   

Site classification of Pondicherry using shear-wave velocity and horizontal-to-vertical spectral ratio     

S. Trupti  K. Goverdhan  K. N. S. S. S. Srinivas  P. Prabhakar Prasad  T. Seshunarayana 《Natural Hazards》2013,69(1):953-964

Site classification studies play a vital role in earthquake hazard assessment since in situ ground conditions substantially affect the characteristics of incoming seismic waves during earthquakes. Flat areas along the coast and rivers generally consist of thick layers of soft clay and sand. Such deposits amplify certain frequencies of ground motion, thereby attributing to an increase in the damage due to an earthquake. Hence, site classification studies have been carried out using shear-wave velocity, ground response, and corresponding amplification at 83 locations in Pondicherry, a coastal city in India. The present study is aimed at estimating the shear-wave velocity through multichannel analysis of surface waves and to compute the average shear-wave velocity (V _S ³⁰ ), stiffness, and N values using empirical relations. Further, site-response studies (horizontal-to-vertical spectral ratio) were conducted to estimate the ground-response frequencies and corresponding amplifications through Nakamura technique. From the results, the study area was classified into three types, i.e., C-class: with V _S ³⁰ in the range of 360–760 m/s, D-class: with V _S ³⁰ in the range of 180–360 m/s, and E-class: with V _S ³⁰  < 180 m/s following the National Earthquake Hazard Reduction Programme norms (BSSC in NEHRP recommended provisions for seismic regulations for new buildings and other structures (FEMA 450), part 1: provisions. Building Seismic Safety Council for the Federal Emergency Management Agency, Washington, 2003). Finally, a site classification map for Pondicherry region has been prepared, which can be used in urban planning and strengthening of existing structures against future earthquakes.  相似文献   

News and notes     

P. Krishnamurthy  K. S. Godhavari  Manish A. Mamtani  Swati Dixit  Md. Firoze Quamar  Ratan Kar  Sita Bora  Quazi A. Rasool  K. V. Subbarao  S. D. Mukherji  C. V. R. K. Prasad  Kakani Nageswara Rao 《Journal of the Geological Society of India》2013,81(6):849-864

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Numerical simulation of cyclonic storms FANOOS, NARGIS with assimilation of conventional and satellite observations using 3-DVAR   总被引：3，自引：2，他引：1  

C. V. Srinivas  V. Yesubabu  K. B. R. R. Hari Prasad  B. Venkatraman  S. S. V. S. Ramakrishna 《Natural Hazards》2012,63(2):867-889

In this work, the impact of assimilation of conventional and satellite data is studied on the prediction of two cyclonic storms in the Bay of Bengal using the three-dimensional variational data assimilation (3D-VAR) technique. The FANOOS cyclone (December 6?C10, 2005) and the very severe cyclone NARGIS (April 28?CMay 2, 2008) were simulated with a double-nested weather research and forecasting (WRF-ARW) model at a horizontal resolution of 9?km. Three numerical experiments were performed using the WRF model. The back ground error covariance matrix for 3DVAR over the Indian region was generated by running the model for a 30-day period in November 2007. In the control run (CTL), the National Centers for Environmental Prediction (NCEP) global forecast system analysis at 0.5° resolution was used for the initial and boundary conditions. In the second experiment called the VARCON, the conventional surface and upper air observations were used for assimilation. In the third experiment (VARQSCAT), the ocean surface wind vectors from quick scatterometer (QSCAT) were used for assimilation. The CTL and VARCON experiments have produced higher intensity in terms of sea level pressure, winds and vorticity fields but with higher track errors. Assimilation of conventional observations has meager positive impact on the intensity and has led to negative impact on simulated storm tracks. The QSCAT vector winds have given positive impact on the simulations of intensity and track positions of the two storms, the impact is found to be relatively higher for the moderate intense cyclone FANOOS as compared to very severe cyclone NARGIS.  相似文献   

Role of asymmetry effect on the specific conductivity of water—A case study     

Parameswara D.  Prasad K.S.S. 《中国地球化学学报》2012,31(3):276-281

Forty-one water samples in each season(both pre-and post-monsoon) were collected from different for-mations of the Kadiri schist belt located in the Anantapur district,Andhra Pradesh.The specific electrical conductiv-ity(EC) of these water samples was measured at 25℃ by using specific conductivity bridge.The specific conductiv-ity values of the water samples were also calculated by multiplying ionic concentrations with conductivity factor.It is found that the observed EC values of all water samples collected in both the seasons are different from the esti-mated EC values because of the electro-chemical properties of ions in water.  相似文献   

Markov chain model to study the occurrence of pre-monsoon thunderstorms over Bhubaneswar,India   总被引：1，自引：0，他引：1  

Surajit Chattopadhyay  Nachiketa Acharya  Goutami Chattopadhyay  Siripurapu Kiran Prasad  Uma Charan Mohanty 《Comptes Rendus Geoscience》2012,344(10):473-482

The present work deals with pre-monsoon thunderstorms over Bhubaneswar belonging to the state of Orissa, India. A Markovian approach has been adopted to discern the probabilistic behavior of the time series of the occurrence and non-occurrence of this hazardous weather event by introducing a dichotomy within the time series. After a painstaking analysis through chi-square tests, we have identified serial independence in a few years and first-order two-state Markovian dependence in a few years (2000, 2001, 2004 and 2006). Finally, for the years of first-order two-state Markovian dependence, it has been observed that the probability of occurrence or non-occurrence of thunderstorm gets higher if the state of the previous day is similar to that of the current day. Furthermore, the probability of getting non-thunderstorm day followed by non-thunderstorm day is higher than the probability of getting thunderstorm day followed by thunderstorm day. It has been also observed that the unconditional climatological probability of the occurrence of severe pre-monsoon thunderstorm implied by the Markov chain is closely in agreement with the observed relative frequencies. However, it could be revealed that Markov chain cannot, in general, be suggested as a predictive tool for pre-monsoon thunderstorms under study without investigating the serial dependence inherent in the time series.  相似文献   

Studies on the variations of heavy metals in the marine sediments off Kalpakkam,East Coast of India   总被引：1，自引：1，他引：0  

K. K. Satpathy  A. K. Mohanty  M. V. R. Prasad  Usha Natesan  S. K. Sarkar 《Environmental Earth Sciences》2012,65(1):89-101

During the last two decades, the coastal environment of southeast India has experienced intense developments in industry, urbanization and aquaculture. Moreover, the 2004 mega tsunami has devastated this coast, thus affecting the coastal sediment characteristics. These two phenomena prompted a study to characterize the sediment, to understand the mechanisms influencing the distribution of heavy metals and to create baseline data for future impact assessment. Results showed that the coastal sediment was carpeted with a mosaic of sand and silty sand with a minor amount of clay. Heavy metal values showed maximum variation for Fe and minimum for Cd. Their average values showed the following decreasing trend: Fe > Cu > Zn > Pb > Cr > Ni > Cd. This study shows that the major source of metals at Kalpakkam coast are land-based anthropogenic ones, such as, discharge from industrial waste, agricultural waste, urban, municipal and slum sewage into the Buckingham canal, which in turn discharges into the sea through backwaters, particularly during northeast monsoon period. A clear signature of the role of backwater discharge increasing the concentration of a few metals in the coastal sediments during monsoon period was observed. Assessments of the degree of pollution, concentration factor (CF), geoaccumulation index (I _geo) and pollution load index (PLI) have been calculated. CF values and I _geo indicated that the coastal sediment is moderately polluted by Cu and Cd. Increase in Cu, Pb and Zn concentration during the monsoon period (October–January) compared to the rest of the year was noticed. Factor analysis and correlation among the heavy metals concluded that Cr, Ni, Cd and Fe are of crustal origin, whereas, Cu, Pb and Zn are from anthropogenic sources. Organic carbon content in the sediment increased during monsoon period, pointing to the role of land runoff and backwater discharge in enhancing its content. The study also elucidates the impact of the recent tsunami in depleting metal content in the coastal sediment as compared to the pre-tsunami period.  相似文献   

Strong ground motion simulation during the November 1759 Earthquake along Serghaya Fault in the metropolitan of Damascus, Syria     

Hussam Eldein Zaineh  Hiroaki Yamanaka  Yadab Prasad Dhakal  Rawaa Dakkak  Mohamad Daoud 《Journal of Seismology》2013,17(4):1295-1319

The seismic hazard potential for metropolitan of Damascus, Syria is mainly controlled by earthquakes along Serghaya Fault which is a branch of Dead Sea Fault System. In this study, strong ground motion due to the November 1759 Earthquake along the fault of Serghaya was estimated with a numerical simulation technique. In the simulation, the Kostrov-like slip-velocity function was used as an input to the discrete wave number method to simulate the strong ground motions in a broadband frequency range. In order to model the incoherent rupture propagation which can excite large high-frequency waves, random numbers are added to arrival time of circular rupture front. MMI intensities calculated from the synthetic ground motions are compared with the observed values by Ambraseys and Barazangi (J Geophys Res 94:4007-4013, 1989). The calculated intensities are in good agreement with the observed ones at the most sites that validate appropriateness of the proposed source model. The PGA and PGV in the eastern region of Damascus city are higher than those in the western region due to the effects of local site amplification. The simulated high-frequency (1.0–6.0 Hz) ground motions for the sites in the Damascus city are higher than the design requirements defined by the Syrian building code. Furthermore, the simulated high-frequency ground motions for sites in the focal region are bigger than the design requirements in the case of the near-fault factors and are not considered. That demonstrates the appropriateness of considering the near-fault factors for a site near the focal region as introduced by the new building code.  相似文献   

Foliar Applied Nickel on Buckwheat (Fagopyrum esculentum) Induced Phenolic Compounds as Potential Antioxidants     

Oksana Sytar  Marian Brestic  Abhay Kumar  M. N. V. Prasad  Nataliya Taran  Iryna Smetanska 《洁净——土壤、空气、水》2013,41(11):1129-1137

In this study, Fagopyrum esculentum (common buckwheat) sprayed with nickel (Ni) (0, 0.5, 1.0, 3.0, and 5.0 mM) for different duration has been investigated for Ni accumulation, malondialdehyde (MDA), total phenolics, and phenolic acids. Ni accumulation significantly increased in dose‐dependent manner. Plants exposed for 72 h, showed visible damages as chlorosis and irreversible necrosis. The MDA and total phenolic contents increased at 24 h of Ni treatments. HPLC data revealed that phenolic acids are in good correlation with concentration and durations of treatments. After 24 and 48 h the contents of chlorogenic, p‐hydroxybenzoic, hesperetic, p‐anisic, and caffeic acids increased in Ni treated leaves. On the other hand, p‐hydroxybenzoic, hesperetic, p‐anisic, p‐coumaric, caffeic acids contents decreased after 72 h of Ni exposure. Vanillic and cinnamic acid followed same pattern and increased significantly at 3.0 and 5.0 mM after 48 h of Ni exposure. It may suggest that buckwheat can be possible hyperaccumulators of Ni, because of high Ni accumulation in tissues through foliar treatment. Furthermore, the analyzed phenolic acids have potential role as antioxidants, which provide tolerance to buckwheat against Ni treatment.  相似文献