Upper mantle anisotropy of southeast Arabia passive margin [Gulf of Aden northern conjugate margin], Oman     

Ali Al-Lazki  Cindy Ebinger  Michael Kendall  George Helffrich  Sylvie Leroy  Christel Tiberi  Graham Stuart  Khalfan Al-Toobi 《Arabian Journal of Geosciences》2011,5(5):925-934

In this study, we used data recorded by two consecutive passive broadband deployments on the Gulf of Aden northern margin, Dhofar region, Sultanate of Oman. The objective of these deployments is to map the young eastern Gulf of Aden passive continental margin crust and upper mantle structure and rheology. In this study, we use shear-wave splitting analysis to map lateral variations of upper mantle anisotropy beneath the study area. In this study, we found splitting magnitudes to vary between 0.33 and 1.0 s delay times, averaging about 0.6 s for a total of 17 stations from both deployment periods. Results show distinct abrupt lateral anisotropy variation along the study area. Three anisotropy zones are identified: a western zone dominated by NW–SE anisotropy orientations, an eastern zone dominated with NE–SW anisotropy orientations, and central zone with mixed anisotropy orientations similar to the east and west zones. We interpret these shorter wavelength anisotropy zones to possibly represent fossil lithospheric mantle anisotropy. We postulate that the central anisotropy zone may be representing a Proterozoic suture zone that separates two terranes to the east and west of it. The anisotropy zones west and east were being used indicative of different terranes with different upper mantle anisotropy signatures.  相似文献   

Robust optimization of subsurface flow using polynomial chaos and response surface surrogates     

Masoud Babaei  Ali Alkhatib  Indranil Pan 《Computational Geosciences》2015,19(5):979-998

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Probability distribution and extreme value analysis of total suspended particulate matter in Kuwait     

Neelamani Subramaniam  Mane Al-Sudairawi  Ali Al-Dousari  Noor Al-Dousari 《Arabian Journal of Geosciences》2015,8(12):11329-11344

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Erratum to: Mobilization and redistribution of major and trace elements in a lateritic profile: the Sheikh-Marut deposit,NW Iran     

Ali Abedini  Ali Asghar Calagari 《Arabian Journal of Geosciences》2015,8(12):10883-10885

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Empirical modeling of plate load test moduli of soil via gene expression programming     

Ali Mollahasani  Amir Hossein Alavi  Amir Hossein Gandomi 《Computers and Geotechnics》2011

New empirical models were developed to predict the soil deformation moduli using gene expression programming (GEP). The principal soil deformation parameters formulated were secant (E_s) and reloading (E_r) moduli. The proposed models relate E_s and E_r obtained from plate load-settlement curves to the basic soil physical properties. The best GEP models were selected after developing and controlling several models with different combinations of the influencing parameters. The experimental database used for developing the models was established upon a series of plate load tests conducted on different soil types at depths of 1–24 m. To verify the applicability of the derived models, they were employed to estimate the soil moduli of a part of test results that were not included in the analysis. The external validation of the models was further verified using several statistical criteria recommended by researchers. A sensitivity analysis was carried out to determine the contributions of the parameters affecting E_s and E_r. The proposed models give precise estimates of the soil deformation moduli. The E_s prediction model provides considerably better results in comparison with the model developed for E_r. The simplified formulation for E_s significantly outperforms the empirical equations found in the literature. The derived models can reliably be employed for pre-design purposes.  相似文献   

A hybrid computational approach to formulate soil deformation moduli obtained from PLT     

Seyyed Mohammad Mousavi  Amir Hossein Alavi  Ali Mollahasani  Amir Hossein Gandomi 《Engineering Geology》2011,123(4):324

In this study, new empirical equations were developed to predict the soil deformation moduli utilizing a hybrid method coupling genetic programming and simulated annealing, called GP/SA. The proposed models relate secant (E_s), unloading (E_u) and reloading (E_r) moduli obtained from plate load–settlement curves to the basic soil physical properties. Several models with different combinations of the influencing parameters were developed and checked to select the best GP/SA models. The database used for developing the models was established upon a series of plate load tests (PLT) conducted on different soil types at various depths. The validity of the models was tested using parts of the test results that were not included in the analysis. The validation of the models was further verified using several statistical criteria. A traditional GP analysis was performed to benchmark the GP/SA models. The contributions of the parameters affecting E_s, E_u and E_r were analyzed through a sensitivity analysis. The proposed models are able to estimate the soil deformation moduli with an acceptable degree of accuracy. The E_s prediction model has a remarkably better performance than the models developed for predicting E_u and E_r. The simplified formulations for E_s, E_u and E_r provide significantly better results than the GP-based models and empirical models found in the literature.  相似文献   

A new empirical estimator of coseismic landslide displacement for Zagros Mountain region (Iran)     

Ali M. Rajabi  Mohammad R. Mahdavifar  M. Khamehchiyan  V. Del Gaudio 《Natural Hazards》2011,59(2):1189-1203

Earthquake-induced landslides are responsible worldwide for significant socioeconomic losses and historically have a prominent position in the list of natural hazards affecting the Iran plateau. As a step toward the development of tools for the assessment and the management of this kind of hazard at regional scale, an empirical estimator of coseismic displacements along potential sliding surfaces was obtained through a regression analysis for the Zagros region, a mountainous Iranian region subjected to earthquake-induced landslides. This estimator, based on the Newmark’s model, allows to evaluate the expected permanent displacement (named “Newmark displacement”) induced by seismic shaking of defined energy on potential sliding surface characterized by a given critical acceleration. To produce regression models for Newmark displacement estimators, a data set was constructed for different critical acceleration values on the basis of 108 accelerometric recordings from 80 Iranian earthquakes with moment magnitudes between 3.6 and 7. The empirical estimator has a general form, proposed by Jibson (Eng Geol 91:209–218, 2007), relating Newmark displacement to Arias intensity (as parameter representing the energy of the seismic forces) and to critical acceleration (as parameter representing the dynamic shear resistance of the sliding mass). As an example of application, this relation was employed to provide a basic document for earthquake-induced landslide hazard assessment at regional scale, according to a method proposed by Del Gaudio et al. (Bull Seismol Soc Am 93:557–569, 2003), applied to the whole Iranian territory, including Zagros region. This method consists in evaluating the shear resistance required to slopes to limit the occurrence of seismically induced failures, on the basis of the Newmark’s model. The obtained results show that the exposure to landslide seismic induction is maximum in the Alborz Mountains region, where critical accelerations up to ~0.1 g are required to limit the probability of seismic triggering of coherent type landslides within 10% in 50 years.  相似文献   

Dynamics of hourly sea level at Hillarys Boat Harbour,Western Australia: a chaos theory perspective     

Rahman Khatibi  Mohammad Ali Ghorbani  Mohammad Taghi Aalami  Kasim Kocak  Oleg Makarynskyy  Dina Makarynska  Mahdi Aalinezhad 《Ocean Dynamics》2011,61(11):1797-1807

Water level forecasting using recorded time series can provide a local modelling capability to facilitate local proactive management practices. To this end, hourly sea water level time series are investigated. The records collected at the Hillarys Boat Harbour, Western Australia, are investigated over the period of 2000 and 2002. Two modelling techniques are employed: low-dimensional dynamic model, known as the deterministic chaos theory, and genetic programming, GP. The phase space, which describes the evolution of the behaviour of a nonlinear system in time, was reconstructed using the delay-embedding theorem suggested by Takens. The presence of chaotic signals in the data was identified by the phase space reconstruction and correlation dimension methods, and also the predictability into the future was calculated by the largest Lyapunov exponent to be 437 h or 18 days into the future. The intercomparison of results of the local prediction and GP models shows that for this site-specific dataset, the local prediction model has a slight edge over GP. However, rather than recommending one technique over another, the paper promotes a pluralistic modelling culture, whereby different techniques should be tested to gain a specific insight from each of the models. This would enable a consensus to be drawn from a set of results rather than ignoring the individual insights provided by each model.  相似文献   

Pesticides Removal Using Conventional and Low‐Cost Adsorbents: A Review     

Javad Zolgharnein  Ali Shahmoradi  Jahanbakhsh Ghasemi 《洁净——土壤、空气、水》2011,39(12):1105-1119

Worldwide pesticide usage has increased dramatically during the last three decades, coinciding with changing practices and increasing by intensive agriculture. This widespread use of pesticides for agricultural and non‐agricultural purposes has resulted in the presence of their residues in various environmental matrices. The occurrence of pesticides and their metabolite transported in rivers, channels, lakes, sea, air, soils, groundwater, and even drinking water, proves the high risk of these chemicals to human health and the environment. Therefore, pesticide removal is of an increasing concern. In this study, a review of the published literature dealing with pesticides removal process is presented. Firstly, pesticide removal by conventional means is briefly considered. Secondly, the use of the low‐cost sorbent through biosorption process is discussed comprehensively. The effect of factors such as pH, contact time, sorbent dosage, initial pesticide concentration, and optimization of biosorption conditions is also discussed. Kinetic, thermodynamic, and mechanism studies are also given. This study shows that both microorganisms and other materials with biological origin like agricultural by‐products may be used to this end. There is a significant potential for pesticide uptake by the use of various pristine and especially modified biosorbents. In the case of living organisms used as removal agents, degradation may also play a role in the total removal observed.  相似文献   

The effect of the electron sound speed on wave propagation in the ionospheric plasma     

Ali Yesil  Mehmet Aydogdu 《Acta Geophysica》2011,59(2):398-406

In this study, the effect of the electron sound speed on the extraordinary wave propagation is calculated without an approximation for either collisional or collisionless cases in the ionospheric plasma by using the real geometry of the Earth’s magnetic field for the Northern Hemisphere. It is observed that there is no remarkable effect on the propagation of the extraordinary wave, especially at reflection altitudes. But it is also observed that the magnitudes of k ² (the square of the wave number) have changed every season, and the phase velocity of wave in warm ionospheric plasma has increased.  相似文献