A Study of Largest Active Region AR12192 of 24th Solar Cycle Using Fractal Dimensions and Mathematical Morphology

Solar System Research - An active region (AR) of the sun is an area of strong magnetic field. Sunspots are frequently formed in an AR. Solar activity exhibits in the form of solar flares and...     

Regionalization of hydrologic parameters of Nash mode

hydrologic models are important tools to estimate runoff from a catchment. Identification of broad based parameters of a hydrologic model for development of direct runoff hydrograph is a key issue for the modelers. Optimization and regionalization of hydrologic parameters for application of Nash’s model is investigated in this paper. Six catchments dominated by hill torrent flows were selected for this purpose. Fifty seven rainfall events were used for regionalization of parameters and about 55 events were used for validation of the results. The hydrologic parameters of the Nash Model, number of linear cascades (N) and storage coefficient (k) were determined using optimization based upon Downhill Simplex method. The data was collected by field measurements and from Water and Power Development Authority (WAPDA) Pakistan. The physical parameters of the catchments were derived from the satellite images of the watersheds with the help of ERDAS software. The performance of the model was assessed by the model efficiency. It is concluded that the conceptual Nash model can simulate direct runoff hydrograph using regional hydrologic parameters with model efficiency of 67%.     

First report of eudialyte occurrence from the Sushina hill region,Purulia district,West Bengal

Eudialyte is a group of hydrated silicate minerals essentially consisting of Na and Zr with a very complex crystal structure, and generally associated with alkaline rocks. The complexity of the eudialyte structure can be understood from the fact that Na alone exist in five distinct sites and extensive solid solubility can occur in almost all cation sites, sometimes one element occupying multiple sites to the extent of exclusion of other elements. Structurally, eudialyte can be represented as Na₁₅[M ₁ ]₆[M 2]₃Zr₃[M ₃ ](Si₂₅O₇₃)(O,OH,H₂O)₃X₂ (Johnsen and Grice, 1999), where M ₁ and M ₂ sites are occupied by Ca, Mn and Fe, M ₃ by Nb and X by OH, Cl and F. In addition, cations like Al, Hf, W, Ta, Sr, Ba and various REEs get incorporated into the eudialyte structure by substitution, and additional site vacancies even may develop in order to maintain electrical neutrality. Eudialyte, approximately of the composition Na₉Ca₈Mn₃Nb(Zr,Ce)₃Si₂₅O₇₃(OH)₂, has hydrothermally replaced albite in the nepheline syenite gneiss exposed south of the Sushina hill of Purulia district, West Bengal. The eudialyte contains ≈2.25 atom% Zr and 0.75 atom% Nb. In addition to eudialyte in nepheline syenite, an unknown Na-Zr silicate (NZS) has also replaced the albite crystals. The NZS contains ≈ 7 atom% Zr with a possible empirical formula of Na₁₂Zr₁₁Si₃₆O₉₅(OH)₁₀. Surface exposures of these rocks are limited at Sushina hill, yet a detailed and systematic investigation on this enigmatic rock is warranted for they may turn out to be a resource for Zr.     

Estimation of fundamental frequency in Dammam City,Eastern Saudi Arabia

Arabian Journal of Geosciences - Dammam City was affected by strong earthquakes from Zagros fold-fault belt of subduction zone. These distant earthquakes of magnitude greater than 6.0 produced...     

Shrinking greenery: Land use and land cover changes in Kurram Agency,Kohi Safid Mountains of north-western Pakistan

Deforestation and other Land Use and Land Cover (LULC) changes, driven by variety of physical and anthropogenic factors, have altered the mountainous environment. Mountains around the world including northern and north western belts of Pakistan are highly sensitive to deforestation and other LULC changes, which have profound impacts on various sectors of bio-physical and socio-economic systems. Assessment of LULC changes has high significance for protection, conservation and monitoring mountainous environment. The present study is an attempt to assess the landscape changes with particular reference to forest cover depletion in Kurram Agency located in the north western mountain belt of Pakistan. For detailed comparative analysis the study area has been divided into three sections, which coincide with the present administrative divisions of the Agency, i.e., Upper, Lower and Central Kurram. Temporal span of this study covers four decades. In this study, land use map of 1970 and land sat satellite imageries of 1987, 2000 and 2014 were used as spatial data sets. The images were processed and classified into six LULC classes through geospatial packages and change detection maps were prepared for each division and time period. Findings of the study reveal two trends in the four major LULC categories. Forest and rangeland have shrunk, on average, by 15% and 7.5% respectively while, bare soil and rocks outcrops have expanded by 89% and agriculture land by 7.2% in Kurram agency. The water bodies and snow cover have minor fluctuation in its land area. Major causes of shrinking greenery is attributed to high influx of Afghan refugees and high energy demand of growing population. However, with outflow of the refugees from Kurram agency the general trend in forest cover has reverted and deforestation rate has slowed down.     

A probabilistic approach to the assessment of uranium resources

This paper presents a probabilistic approach to the estimation of uranium resources that allows for the integration of geologic observations with the experience and judgment of geologists. The paper focuses on estimating roll-front type deposits. The approach is based on a quantitative material balance model of ore formation that describes the quantity of uranium resources in terms of several key parameters constituting the quantity of uranium entering a host, and the fraction of the entering uranium that has been precipitated. The parameters cannot necessarily be measured in the field, but they can be inferred from available information and interpretation of field observations. The key to this approach is eliciting these inferences from geologists, representing the uncertainties inherent in drawing the geologic inferences as probability distributions, and combining the distributions to arrive at a probability distribution for uranium resources in a region. This paper presents the model, procedures for eliciting subjective probabilities and updating the distribution over resources within a Bayesian framework, and a demonstration of the procedure by obtaining estimates for three roll-front type deposits in Wyoming.     

Crustal structure of the northern Levant region: multiple source Werner deconvolution estimates for Bouguer gravity anomalies

The opening of the Gulf of Aden and the Red Sea, and the collision of the Arabian plate with the jigsaw southern margin of the Anatolian plate have sheared the Sinai-Levant microplate off the NW part of the Arabian plate, and created the left-lateral Dead Sea (Levant) transform fault. The structural setting of the northern Levant region, particularly Lebanon and the Palmyrides, has been complicated by detachments along incompetent evaporitic horizons, roughly separating the post-Triassic succession from the underlying crustal material. The interpretation of the multiple source Werner deconvolution (MSWD) estimates of Bouguer gravity profiles, which were separately calculated for Syria and Lebanon, integrated with the available geological and geophysical results leads to the following interpretations: (1) the crust of Syria thickens southeastwards from approximately 32 km under the Al-Ghab Graben to >36 km under the Aleppo high, the Palmyride fold belt and the Rutbah high; (2) the lower-crustal (basaltic) layer thickens northwestwards from the hinterland to the Al-Ghab graben at the expense of the overlying andesitic layer; (3) the Mid-Beqa'a fault is delineated by the MSWD estimates in Lebanon and its NE extension in Syria; (4) the Phanerozoic section in the southwesternmost parts of the Palmyrides is ∼ 13 km thick, and the shortening there could exceed 30 km; (5) the Palmyride fold belt, and the Serghaya and Mid-Beqa'a faults could have accounted for about 70 km of the 105 km left-lateral displacement along the southern segment of the Dead Sea transform fault system, without transmission to the Syrian (northern) segment of the fault system; (6) the splitting of the Dead Sea transform fault in the Kuleh Depression into the Serghaya. Mid-Beqa'a, Yammouneh and Roum faults could be explained by the rotation of the detached post-Triassic succession over a stable deep left-lateral fracture of the Dead Sea fault in the underlying crustal material.