Isotope–geochemical characterization and geothermometrical modeling of Uttarakhand geothermal field,India     

Sitangshu Chatterjee  Uday Kumar Sinha  Archana. S. Deodhar  Md. Arzoo Ansari  Nathu Singh  Ajay Kumar Srivastava  R. K. Aggarwal  Ashutosh Dash 《Environmental Earth Sciences》2017,76(18):638

Uttarakhand geothermal area, located in the central belt of the Himalayan geothermal province, is one of the important high temperature geothermal fields in India. In this study, the chemical characteristics of the thermal waters are investigated to identify the main geochemical processes affecting the composition of thermal waters during its ascent toward the surface as well as to determine the subsurface temperature of the feeding reservoir. The thermal waters are mainly Ca–Mg–HCO₃ type with moderate silica and TDS concentrations. Mineral saturation states calculated from PHREEQC geochemical code indicate that thermal waters are supersaturated with respect to calcite, dolomite, aragonite, chalcedony, quartz (SI > 0), and undersaturated with respect to gypsum, anhydrite, and amorphous silica (SI < 0). XRD study of the spring deposit samples fairly corroborates the predicted mineral saturation state of the thermal waters. Stable isotopes (δ¹⁸O, δ²H) data confirm the meteoric origin of the thermal waters with no oxygen-18 shift. The mixing phenomenon between thermal water with shallow ground water is substantiated using tritium (³H) and chemical data. The extent of dilution is quantified using tritium content of thermal springs and non-thermal waters. Classical geothermometers, mixing model, and multicomponent fluid geothermometry modeling (GeoT) have been applied to estimate the subsurface reservoir temperature. Among different classical geothermometers, only quartz geothermometer provide somewhat reliable estimation (96–140 °C) of the reservoir temperature. GeoT modeling results suggest that thermal waters have attained simultaneous equilibrium with respect to minerals like calcite, quartz, chalcedony, brucite, tridymite, cristobalite, talc, at the temperature 130 ± 5 °C which is in good agreement with the result obtained from the mixing model.  相似文献   

New magnitude scaling relations for earthquake early warning in the Alborz region,Iran     

Mohammad Sasani  Mohammad Reza Ghayamghamian  Anooshiravan Ansari 《Acta Geophysica》2018,66(6):1375-1382

Rapid magnitude estimation relations for earthquake early warning systems in the Alborz region have been developed based on the initial first seconds of the P-wave arrival. For this purpose, a total of 717 accelerograms recorded by the Building and Housing Research Center in the Alborz region with the magnitude (M_w) range of 4.8–6.5 in the period between 1995 and 2013 were employed. Average ground motion period (\( \tau_{\text{c}} \)) and peak displacement (\( P_{\text{d}} \)) in different time windows from the P-wave arrival were calculated, and their relation with magnitude was examined. Four earthquakes that were excluded from the analysis process were used to validate the results, and the estimated magnitudes were found to be in good agreement with the observed ones. The results show that using the proposed relations for the Alborz region, earthquake magnitude could be estimated with acceptable accuracy even after 1 s of the P-wave arrival.  相似文献   

Variable Mass Body Motion in the Perturbed Robes Configuration     

Ansari  Abdullah A.  Sahdev  Shiv K. 《Astronomy Reports》2022,66(7):595-605

Astronomy Reports - This paper presents the motion properties of the smallest body, which is moving inside the spherical shell filled with homogeneous incompressible viscous fluid, and also assumes...  相似文献   

Dynamical Properties of Body with Variable Mass in a Fifth-degree Hénon–Heiles System     

Abouelmagd  Elbaz I.  Ansari  Abdullah A. 《Astronomy Reports》2022,66(1):64-74

Astronomy Reports - The aim of this work is to investigate the motion properties of the infinitesimal body in the frame of the fifth-degree generalized Hénon–Heiles (GHH) potential. We...  相似文献   

Did the 1983 Charazeh earthquake trigger the destructive 1990 Rudbar earthquake?     

Khalil Sarkarinejad  Shoja Ansari 《International Journal of Earth Sciences》2015,104(1):309-319

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Numerical analysis of soilbags under compression and cyclic shear     

Yousef Ansari  Richard Merifield  Haruyuki Yamamoto  Daichao Sheng 《Computers and Geotechnics》2011

This paper presents a finite element model for analysing the behaviour of granular material wrapped with polyethylene bags under vertical compression and cyclic shearing. The simple Mohr–Coulomb model is used to represent the soil behaviour. The polyethylene bag is represented by a linear-elastic–perfect-plastic model. The soil-bag interface is modelled with contact constraints. The main purpose of the numerical analysis is to validate the anticipated performance of soilbags under various loading conditions and hence the effectiveness of soilbags as a method of ground improvement.  相似文献   

Effect of geology and geomorphology on landuse/landcover in Himalayan foothill, Dehradun     

Ziaur Rehman Ansari  L. A. K. Rao  Sameer Saran 《Journal of the Geological Society of India》2013,81(6):827-834

A detailed geological, geomorphological and landuse/landcover study has been carried in a small watershed of Himalaya by visual interpretation of FCC prepared from band 123 of ASTER satellite imagery. On the basis of interpretation and field check, major litounits identified in the study area include Lesser Himalaya conglomerate consisting of quartzite, granite, phyllite boulder and pebble, Middle Siwalik sandstone and Upper Siwalik boulder beds and valley fill with Doon gravel of Holocene age. Geomorphologically the study area is characterized by typical Himalayan topography with rugged terrain. Various landforms identified and recognized include, Doon Fan Gravel Terrace, Doon Fan Gravel Dissected hill, Sub Recent Fan Terrace, Moderately Dissected Structural Hill, Piedmont Dissected Slope, River Terrace, Channel Bar and River channel. Supervised classification of ASTER False Colour Composite (FCC) (123) shows that the major landuse category in the study area is agriculture while major landcover class is forest covered land. The study shows the effect of geology and geomorphology on the type of landuse and landcover in an active tectonic zone of the study area.  相似文献   

2D and 3D rockfall hazard analysis and protection measures for Saptashrungi Gad Temple,Vani, Nashik,Maharashtra – A case study     

M. K. Ansari  M. Ahmad  Rajesh Singh  T. N. Singh 《Journal of the Geological Society of India》2018,91(1):47-56

The Saptashrungi gad temple (SGT) situated on basaltic hills belongs to Deccan volcanic of Upper Cretaceous to Lower Eocene, is one among the 51 Shakti Peeths and most holy place for pilgrims. Rockfall is a major problem in the past and causing danger to the lives of the villagers settled at the toe of the SGT hill as well as the pilgrims who perform parikrama along the tracks. On the evening of 16 April 2011, an old woman died due to rockfall at SGT hill when she was performing parikrama, moreover, two persons got injured during the deliverance process of this old woman from the continuous rockfall activity. The problem of rockfall could be linked to rainfall, jointing, weathering, man-made or the compounding of all. In this research, the rockfall hazard analysis at SGT hill is assessed using both 2D and 3D rockfall programs along the two parikrama paths: Parikrama Path 1 (or the Badi Parikrama Path ‘BPP’), and Parikrama Path 2 (or the Chhoti Parikrama Path ‘CPP’). Also, the study area of the SGT hill has been divided into eight zones (Zone#01 to Zone#08), based on field observations, orientations of joint sets and hill slope faces and eighteen topographic profiles (AA' to RR') have been taken from these eight zones for rockfall analysis. A detailed topographic survey along with field investigation has been carried out along the temple for ascertaining the nature of rock, discontinuity orientations, and slope geometry. DEM has been generated using topographic profile in ArcGIS to facilitate the 3D rockfall analysis. Maximum rock block sizes are taken into the analysis and run-out distance, bounce height, kinetic energy and velocity of the basaltic blocks are evaluated separately. Based on the analyzed data, the rockfall hazard zone map has been prepared and site having potential rockfall risks have been identified. Finally, wire/net meshing has been proposed after removal of unstable blocks as a stabilization and protection measures.It is worth mentioning here that for the first time rockfall hazard assessment was made in such detail for a site. Suggestions made are implemented by the State Government for the protection of the temple as well as the life of pilgrims performing the parikrama from the rockfall.  相似文献   

The probability distributions and fractal dimension of sunspot cycles associated with ENSO phenomena     

Asma Zaffar  Shaheen Abbas  Muhammad Rashid Kamal Ansari 《Arabian Journal of Geosciences》2018,11(3):63

Various methods have been used to secure the certainty of significant relations among the sunspot cycles and some of the terrestrial climate parameters such as temperature, rainfall, and ENSO. This study investigates the behavior of ENSO cycles and mean monthly sunspot cycles. Sunspot cycles range from 1755 to 2016 whereas, ENSO cycles range from 1866 to 2012. In this regard, the appropriateness of distributions is investigated with the help of Kolmogorov-Smirnov D, Anderson-Darling, and chi-square tests. It is found that most of the sunspot cycle follows generalized Pareto distribution whereas, generalized extreme value distribution was found appropriate for ENSO cycles. Probability distribution is used to analyze the behavior of each sunspot cycle and ENSO cycle separately. Probability distribution indicates the tail behavior of each cycle; tail explored correlation cycles. Furthermore, self-similar and self-affine fractal dimension methods are used to compute Hurst exponents to determine the persistency of the available data. Fractal dimension has an ability to study the complexity involved in sunspot and ENSO cycles. The fractal dimension and Hurst exponent describe persistency (smoothness) and complexity of data. Hurst exponent measures long-term behavior of time series, making it more helpful for forecasting. This is the measure of regularity or irregularity (chaos) of the time function in the form of their persistency or anti-persistency, respectively. Hurst exponents are computed using rescaled range analysis method and box counting methods. Both these methods are suitable for long-term forecasting. The results of this study confirm that during the period 1980–2000, ENSO cycles were very active. Simultaneously, ENSO was active for the periods 1982–1983, 1986–1987, 1991–1993, 1994–1995, and 1997–1998; these periods include two strongest periods of the century viz., 1982–1983 and 1997–1998. Sunspot cycles and ENSO cycles both were found to be persistent. Self-similar fractal dimensions exhibited a better persistency and a better correlation as compared to self-affine fractal dimension. This research is a part of a larger research project investigating the correlation of sunspot cycles and ENSO cycles, and the influence of ENSO cycles on variations of the local climatic parameters which in turn depends on solar activity changes.  相似文献   

Municipal Solid Waste Management in Moradabad City,India     

Masood Ahsan Siddiqui  Syed Mohammad Rashid  Lubna Siddiqui  Shahzad Ali Ansari 《Journal of the Indian Society of Remote Sensing》2012,40(1):109-119

The paper tries to estimate the rate of waste generation per head/per day, to identify suitable sites for waste disposal, to find out optimal route for collection vehicles and to analyze the financial aspects of solid waste management in Moradabad City, India.The study is based on sample of 2,500 households and secondary data. The City generates about 318 tones of solid waste with an average per capita rate of 460 gram per day. Collection and disposal efficiency is nearly 64%. Sensitivity analysis of the present disposal site as per the norms of Central Pollution Control Board indicates that it is moderately suitable. Subsequently two new disposal sites were identified. Redefined routes and related issues were evaluated in financial terms. It is estimated that by adopting the proposed plan, the expenditure on waste management will increase by about 52%, but at the same time about 90% of city area and 95% of city population will be served.  相似文献