Statistical landslide susceptibility assessment of the Mansehra and Torghar districts,Khyber Pakhtunkhwa Province,Pakistan     

Jewgenij Torizin  Michael Fuchs  Adnan Alam Awan  Ijaz Ahmad  Sardar Saeed Akhtar  Simon Sadiq  Asif Razzak  Daniel Weggenmann  Faseeh Fawad  Nimra Khalid  Faisan Sabir  Ahsan Jamal Khan 《Natural Hazards》2017,87(2):757-771

This paper presents laboratory experiments and numerical simulations of effects of submerged obstacles on tsunami-like solitary wave and its run-up. This study was carried out for the breaking and non-breaking solitary waves on 1:19.85 uniform slope which contains a submerged obstacle. New laboratory experiments are performed to describe the mitigation of tsunami amplitude and run-up under the effect of submerged obstacles. We are based on experimental results obtained to validate the numerical model. The numerical modeling using COULWAVE aims essentially to show the effect of the obstacle on the shape of solitary wave and the limit of this effect. Using a multiple nonlinear regression, we have determined a model to estimate height of run-up according to the amplitude of the wave and the obstacle peak depth.  相似文献   

Crustal attenuation characteristics of S-waves beneath the Eastern Tohoku region,Japan          下载免费PDF全文

Muhammad Adeel Arshad 《地震科学（英文版）》2016,29(5):259-269

An inversion method was applied to crustal earthquakes dataset to find S-wave attenuation characteristics beneath the Eastern Tohoku region of Japan.Accelerograms from 85 shallow crustal earthquakes up to25 km depth and magnitude range between 3.5 and 5.5were analyzed to estimate the seismic quality factor Q_s. A homogeneous attenuation model Q_s for the wave propagation path was evaluated from spectral amplitudes, at 24 different frequencies between 0.5 and 20 Hz by using generalized inversion technique. To do this, non-parametric attenuation functions were calculated to observe spectral amplitude decay with hypocentral distance. Then, these functions were parameterized to estimate Q_s. It was found that in Eastern Tohoku region, the Q_s frequency dependence can be approximated with the function 33 f~(1.22) within a frequency range between 0.5 and 20 Hz. However,the frequency dependence of Q_s in the frequency range between 0.5 and 6 Hz is best approximated by Q_s(f) = 36f~(0.94) showing relatively weaker frequency dependence as compared to the relation Q_s(f) = 6 f~(2.09) for the frequency range between 6 and 15 Hz. These results could be used to estimate source and site parameters for seismic hazard assessment in the region.  相似文献   

Water Quality Characterization of the Siling Reservoir (Zhejiang,China) Using Water Quality Index          下载免费PDF全文

Naveedullah Naveedullah  Muhammad Zaffar Hashmi  Chunna Yu  Chaofeng Shen  Niaz Muhammad  Hui Shen  Yingxu Chen 《洁净——土壤、空气、水》2016,44(5):553-562

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Effect of Shale Distribution on Hydrocarbon Sands Integrated with Anisotropic Rock Physics for AVA Modelling: A Case Study     

Aamir Ali  Zubair  Matloob Hussain  Khaista Rehman  Muhammad Toqeer 《Acta Geophysica》2016,64(4):1139-1163

Shales can be distributed in sand through four different ways; laminated, structural, dispersed and any combination of these aforementioned styles. A careful analysis of well log data is required for the determination of shale distribution in sand affecting its reservoir quality. The objective of this study is to characterize the effect of shale distribution on reservoir quality of sands using well log data. The correlation of well data in terms of lithology has revealed four sand and three shale layers in Lower Goru Formation acting as a major reservoir in the study area. Our results indicate that the laminated type of shale distribution prevails at the Basal sand level, which does not affect its reservoir quality greatly. The remaining layers of variable vertical extent show a variety of shale distribution models affecting their reservoir quality adversely. We also present anisotropic rock physics modelling for AVA analysis at Basal sand level.  相似文献   

Efficacy of Rhizobia for Improving Photosynthesis,Productivity, and Mineral Nutrition of Maize          下载免费PDF全文

Muhammad Baqir Hussain  Zahir Ahmad Zahir  Hafiz Naeem Asghar  Rafia Mubaraka  Muhammad Naveed 《洁净——土壤、空气、水》2016,44(11):1564-1571

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Iron content variations in sphalerite and their effects on reflectance and internal reflections under reflected light     

Salih Muhammad Awadh 《Arabian Journal of Geosciences》2009,2(2):139-142

Reflectance (R%) and internal reflections (IR) in the iron variant, sphalerite, are investigated by using the scanning electron microprobe and reflected light microscope. Iron contents in sphalerite positively affect reflectance and can be considered as a control factor of internal reflections color. Internal reflections of sphalerite grains that contain less than 10% Fe appear to be whitish yellow color but are with reddish brown color when Fe rises to 10% to 17%. This work is an effort for developing ore microscopy and ore petrography technique by using the optical properties as a geochemical tool for fast preliminary estimating iron content in sphalerite by using reflected light microscope.  相似文献   

The Impact of Geology of Recharge Areas on Groundwater Quality: A Case Study of Zhob River Basin,Pakistan   总被引：1，自引：0，他引：1  

Muhammad Umar  Amir Waseem  Muhammad Amjad Sabir  Akhtar Muhammad Kassi  Abdul Salam Khan 《洁净——土壤、空气、水》2013,41(2):119-127

Groundwater is a major source of water supply for domestic and irrigation uses in semiarid, remote but rapidly developing Kilasaifullah district part of Zhob River Basin, located at Pakistan–Afghanistan Border. Zhob River is among few major rivers of perennial nature in Balochistan, which flows from WSW to ENE and falls in Gomal River, a tributary of Indus River. Keeping in view the important geopolitical position and rapid development of the region, this study is primarily focused on groundwater chemistry for contamination sources as well as agriculture development. Water samples from open and tube wells are analyzed and calculated for electrical conductivity (EC), total dissolved solids (TDS), turbidity, pH, K⁺, Na⁺, Ca²⁺, Mg²⁺, HCO, Cl^?, NO, SO, PO, sodium percent (Na%), sodium adsorption ratio (SAR), Kelly's index (KI), and heavy metals (Fe, Cu, Cr, Zn, Pb, and Mn). On the basis of the chemical constituents two zones within the study area are identified and possible causes of the contaminants are pointed out. Two recharge areas were responsible for the different chemical results in groundwater, e.g., zone A was recharged from NNW saline geological formations (Nisai, Khojak, Multana, Bostan formations, and Muslim Bagh ophiolites), which are concentrated with high sodium and chloride. On the other hand Zone B was sourced from SSW from carbonate rich rocks (Alozai, Loralai, Parh formations, and Muslim Bagh ophiolites). The groundwater is classified as C2–S1, C3–S1, C3–S2, C4–S2 on the basis of EC and SAR values which indicate that most of the water of both zones can be used for irrigation safely except the samples plotted in C3–S2 and C4–S2 categories which could be dangerous for soil and crops. Groundwater samples are plotted in good to permissible limits with some samples excellent to good and few samples belong to doubtful category based on sodium percent. Groundwater of zone A is unsuitable for irrigation use due to higher values of KI (more than one) but water of zone B are good for irrigation based on KI. In general, water of both zones is suitable for irrigation but care should be taken during the selection of crops which are sensitive to alkalinity or sodium hazards particularly in zone A.  相似文献   

Evaluation of Bioavailability and Partitioning of Aluminum in Sediment Samples of Different Ecosystems by Modified Sequential Extraction Methods     

Sumaira Khan  Tasneem G. Kazi  Muhammad B. Arain  Nida F. Kolachi  Jameel A. Baig  Hassan I. Afridi  Abdul Q. Shah 《洁净——土壤、空气、水》2013,41(8):808-815

Sequential extraction procedures are widely used to characterize the different operational fractions with different potential toxicity of metals in environmental solid samples. The present work describes the application of different analytical approaches for sequential extraction of aluminum to evaluate its mobility, availability, and persistent chemical forms in sediment samples of different fresh water ecosystems (lake, canal, and river). The conventional BCR three‐stage sequential extraction procedure (C‐BCR) was modified at each stage, by applying ultrasonic device (U‐BCR), in order to shorten the required shaking time of 16 h for each three steps (excluding the hydrogen peroxide digestion in step 3, which was not performed with ultrasonic bath), could be completed in 40, 50, and 45 min, respectively. The aluminum in all extracts were determination by atomic absorption spectrometry using nitrous oxide – acetylene flame. The accuracy of results obtained from C‐BCR and proposed U‐BCR was verified with literature reported values of certified sediment sample (BCR 701). The overall recoveries of aluminum obtained by proposed U‐BCR were found in the range of 96.7–113% of those values obtained with C‐BCR for all fractions. Use of ultrasonic device, provided a large saving in extraction time relative to conventional shaking. It was observed that major part of Al in real sediment samples (80–83% of total Al) were bound to residual fraction. The acid soluble fraction of aluminum extracted by 0.11 mol/L CH₃COOH has good correlation with aluminum content in corresponding water samples of each ecosystem.  相似文献   

Exploitation of TerraSAR-X Data for Land use/Land Cover Analysis Using Object-Oriented Classification Approach in the African Sahel Area, Sudan     

Khalid Biro  Biswajeet Pradhan  Hussein Sulieman  Manfred Buchroithner 《Journal of the Indian Society of Remote Sensing》2013,41(3):539-553

Recently, object-oriented classification techniques based on image segmentation approaches are being studied using high-resolution satellite images to extract various thematic information. In this study different types of land use/land cover (LULC) types were analysed by employing object-oriented classification approach to dual TerraSAR-X images (HH and HV polarisation) at African Sahel. For that purpose, multi-resolution segmentation (MRS) of the Definiens software was used for creating the image objects. Using the feature space optimisation (FSO) tool the attributes of the TerraSAR-X image were optimised in order to obtain the best separability among classes for the LULC mapping. The backscattering coefficients (BSC) for some classes were observed to be different for HH and HV polarisations. The best separation distance of the tested spectral, shape and textural features showed different variations among the discriminated LULC classes. An overall accuracy of 84 % with a kappa value 0.82 was resulted from the classification scheme, while accuracy differences among the classes were kept minimal. Finally, the results highlighted the importance of a combine use of TerraSAR-X data and object-oriented classification approaches as a useful source of information and technique for LULC analysis in the African Sahel drylands.  相似文献   

A geocomputational analysis of Twitter activity around different world cities     

Muhammad Adnan  Alistair Leak  Paul Longley 《地球空间信息科学学报》2013,16(3):145-152

The penetration and use of social media services differs from city to city. This paper is aimed to provide a comparison of the use of Twitter between different cities of the world. We present a temporal analysis of activity on Twitter in 15 cities. Our study consists of two parts: First, we created temporal graphs of the activity in the 15 cities, through which hours of high and low activity could be identified. Second, we created heat map visualizations of the Twitter activities during the period of 19 September 2012–25 September 2013. The heat map visualizations make the periods of intense and sparse activity apparent and provide a snapshot of the activity during the whole year.  相似文献