Tectonic implication of geomorphometric analyses along the Saravan Fault: evidence of a difference in tectonic movements between the Sistan Suture Zone and Makran Mountain Belt     

Roghayeh KASHANI  Abdolreza PARTABIAN  Ahmad NOURBAKHSH 《山地科学学报》2019,(5)

In this paper, remote sensing techniques,as well as field studies, have been used to investigate the geomorphological processes and landscape evolution along the Saravan Fault, SE Iran to highlight how topographic features were influenced by active tectonics. Quantitative geomorphic analysis was carried out using mountain-front sinuosity(Smf),valley floor width-valley height ratio(Vf), drainage basin asymmetry factor(Af), Hypsometric integral(Hi), drainage basin shape index(Bs), mean axial slope of channel(MASC), standard deviation of topography(STD) and index of active tectonic(Iat).Remote sensing techniques, as well as field studies revealed that the Saravan Fault have three parts trending N-S, NW-SE, and E-W. Obtained results show that basins with high Iat index are located at where the strike of the Saravan Faults changes and where several strike-slip faults are crossed the Saravan fault.  相似文献   

Damage detection of 3D structures using nearest neighbor search method     

Ali Abasi  Vahid Harsij  Ahmad Soraghi 《地震工程与工程振动(英文版)》2021,20(3):702-722

An innovative damage identification method using the nearest neighbor search method to assess 3 D structures is presented. The frequency response function was employed as the input parameters to detect the severity and place of damage in 3 D spaces since it includes the most dynamic characteristics of the structures. Two-dimensional principal component analysis was utilized to reduce the size of the frequency response function data. The nearest neighbor search method was employed to detect the severity and location of damage in different damage scenarios. The accuracy of the approach was verified using measured data from an experimental test; moreover, two asymmetric 3 D numerical examples were considered as the numerical study. The superiority of the method was demonstrated through comparison with the results of damage identification by using artificial neural network. Different levels of white Gaussian noise were used for polluting the frequency response function data to investigate the robustness of the methods against noise-polluted data. The results indicate that both methods can efficiently detect the damage properties including its severity and location with high accuracy in the absence of noise, but the nearest neighbor search method is more robust against noisy data than the artificial neural network.  相似文献   

A finite element method for modeling coupled flow and deformation in porous fractured media          下载免费PDF全文

Ahmad Pouya 《国际地质力学数值与分析法杂志》2015,39(16):1836-1852

Modeling the flow in highly fractured porous media by finite element method (FEM) has met two difficulties: mesh generation for fractured domains and a rigorous formulation of the flow problem accounting for fracture/matrix, fracture/fracture, and fracture/boundary fluid mass exchanges. Based on the recent theoretical progress for mass balance conditions in multifractured porous bodies, the governing equations for coupled flow and deformation in these bodies are first established in this paper. A weak formulation for this problem is then established allowing to build a FEM. Taking benefit from recent development of mesh‐generating tools for fractured media, this weak formulation has been implemented in a numerical code and applied to some typical problems of hydromechanical coupling in fractured porous media. It is shown that in this way, the FEM that has proved its efficiency to model hydromechanical phenomena in porous media is extended with all its performances (calculation time, couplings, and nonlinearities) to fractured porous media. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

Micro-Macro Analysis and Phenomenological Modelling of Salt Viscous Damage and Application to Salt Caverns     

Cheng Zhu  Ahmad Pouya  Chloé Arson 《Rock Mechanics and Rock Engineering》2015,48(6):2567-2580

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Analysis of current trends in climatic parameters and its effect on discharge of Satluj River basin,western Himalaya     

Riyaz Ahmad Mir  Sanjay K. Jain  Arun K. Saraf 《Natural Hazards》2015,79(1):587-619

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Using large‐scale climatic patterns for improving long lead time streamflow forecasts for Gunnison and San Juan River Basins     

Ajay Kalra  William P. Miller  Kenneth W. Lamb  Sajjad Ahmad  Thomas Piechota 《水文研究》2013,27(11):1543-1559

In a water‐stressed region, such as the western United States, it is essential to have long lead times for streamflow forecasts used in reservoir operations and water resources management. Current water supply forecasts provide a 3‐month to 6‐month lead time, depending on the time of year. However, there is a growing demand from stakeholders to have forecasts that run lead times of 1 year or more. In this study, a data‐driven model, the support vector machine (SVM) based on the statistical learning theory, was used to predict annual streamflow volume with a 1‐year lead time. Annual average oceanic–atmospheric indices consisting of the Pacific decadal oscillation, North Atlantic oscillation (NAO), Atlantic multidecadal oscillation, El Niño southern oscillation (ENSO), and a new sea surface temperature (SST) data set for the ‘Hondo’ region for the period of 1906–2006 were used to generate annual streamflow volumes for multiple sites in the Gunnison River Basin and San Juan River Basin, both located in the Upper Colorado River Basin. Based on the performance measures, the model showed very good forecasts, and the forecasts were in good agreement with measured streamflow volumes. Inclusion of SST information from the Hondo region improved the model's forecasting ability; in addition, the combination of NAO and Hondo region SST data resulted in the best streamflow forecasts for a 1‐year lead time. The results of the SVM model were found to be better than the feed‐forward, back propagation artificial neural network and multiple linear regression. The results from this study have the potential of providing useful information for the planning and management of water resources within these basins. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Review: Assessment and modeling of seawater intrusion in coastal aquifers of the Arabian Peninsula     

Akhtar  Javed  Sana  Ahmad  Tauseef  Syed Mohammed 《Hydrogeology Journal》2023,31(5):1121-1145

Hydrogeology Journal - Significant urbanization and industrialization, combined with strong population growth, have been witnessed in the Arabian Peninsula (Oman, United Arab Emirates, Saudi...  相似文献   

Potential sea-level rise effects on the hydrodynamics and transport processes in Hudson–Raritan Estuary,NY–NJ     

Feizabadi  Sajjad  Rafati  Yashar  Ghodsian  Masoud  Akbar Salehi Neyshabouri  Ali  Abdolahpour  Maryam  Mazyak  Ahmad Rezaee 《Ocean Dynamics》2022,72(6):421-442

Ocean Dynamics - The climatic change has led to the sea-level rise (SLR), which is expected to continue based on the current industrial and human activities. Previous studies indicated that most of...  相似文献   

Can observational growth rate data favor the clustering dark energy models?     

Ahmad Mehrabi  Mohammad Malekjani  Francesco Pace 《Astrophysics and Space Science》2015,356(1):129-135

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Investigating the application of pixel-level and product-level image fusion approaches for monitoring surface water changes     

Komeil Rokni  Tajul Ariffin Musa  Sharifeh Hazini  Anuar Ahmad  Karim Solaimani 《Natural Hazards》2015,78(1):219-230

The aim of this paper was to investigate the suitability of the pixel-level and product-level image fusion approaches to detect surface water changes. In doing so, firstly, the principal component analysis technique was applied to Landsat TM 2010 multispectral image to generate the PC components. Several pixel-level image fusion techniques were then performed to merge the Landsat ETM+ 2000 panchromatic with the PC1PC2PC3 band combination of Landsat TM 2010 imagery to highlight the surface water changes between the two images. The suitability of the resulting fused images for surface water change detection was evaluated quantitatively and visually. Finally, the support vector machine (SVM) technique was applied to the qualified fused images to map the highlighted changes. Furthermore, a product level fusion (PLF) approach based on various satellite-derived indices was employed to detect the surface water changes between ETM+ 2000 and TM 2010 images. The accuracy of the resulting change maps was assessed based on a reference change map produced using visual interpretation. The results demonstrated the effectiveness of the proposed approaches for surface water change detection, especially using the Gram Schmidt-SVM, PLF-NDWI, and PLF-NDVI methods which improved the accuracy of change detection over 99.70 %.  相似文献