Characterization of natural hydrocarbon seepage in the South Caspian Sea off Iran using satellite SAR and geological data     

Andrei Yu. Ivanov  Hadi Gerivani  Natalia V. Evtushenko 《Marine Georesources & Geotechnology》2020,38(5):527-538

Abstract

Two groups of oil slicks have been repeatedly detected in the Southern Caspian Sea, off Cape Sefidrud and close to the Iranian coast of the sea on the synthetic aperture radar (SAR) images acquired by the Sentinel-1A and Sentinel-1B satellites in April–June 2018. Analysis of the SAR images together with bathymetry, geological and geophysical data in geographic information system showed that these manifestations (oil slicks) visible on the sea surface have natural origin, related to the bottom seepage phenomenon and are associated with existing hydrocarbon system. Oil slicks are concentrated over the continental slope and related to local geological formations of the sedimentary cover having oil deposits related to paleo-delta of Sefidrud River. Our evidence shows that two seeps in this area are active and repeating. It is concluded that the SAR is an excellent tool for monitoring of seepage phenomenon. Moreover, results indicate that the use of remote methods to identify offshore natural oil seeps related to existing active petroleum system can be considered as a well-accepted approach to support oil and gas exploration in frontier areas such as the South Caspian Basin.  相似文献   

The analysis of trend variations of reference evapotranspiration via eliminating the significance effect of all autocorrelation coefficients     

Babak Amirataee  Majid Montaseri  Hadi Sanikhani 《Theoretical and Applied Climatology》2016,123(1-2):131-139

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Multi-well and multi-tracer tests to characterize the groundwater aquifers in southern Kuwait     

K. Hadi  U. Saravana Kumar  M. Al-Senafy  A. Mukhopadhyay  A. Al-Khalid  K. Al-Fahad  H. Bhandary 《Environmental Earth Sciences》2016,75(20):1340

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Green biocompatible approach to reduce the toxic gases and dust caused by the blasting in surface mining     

Jafar Abdollahisharif  Ezzeddin Bakhtavar  Hadi Nourizadeh 《Environmental Earth Sciences》2016,75(3):191

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Tschermak fractionation in calc-alkaline magmas: the Eocene Sabzevar volcanism (NE Iran)     

Federico Lucci  Federico Rossetti  John Charles White  Hadi Shafaii Moghadam  Alireza Shirzadi  Mohsen Nasrabady 《Arabian Journal of Geosciences》2016,9(10):573

Calc-alkaline arc magmatism at convergent plate margins is volumetrically dominated by metaluminous andesites. Many studies highlighted the importance of differentiation via fractionation processes of arc magmas, but only in the last decades, it has been demonstrated that not all rock-forming minerals may affect the evolution of calc-alkaline suites. In particular, a major role exerted by Al-rich hornblende amphibole as fractionating mineral phase has been documented in many volcanic arc settings. The aim of this work is to understand the role of the Tschermak molecule (CaAlAlSiO₆) hosted in the hornblende and plagioclase fractionation assemblage in driving magma differentiation in calc-alkaline magmatic suites. We explore this issue by applying replenishment–fractional crystallization (RFC) and rare earth element–Rayleigh fractional crystallization (REE-FC) modeling to the Sabzevar Eocene (ca. 45–47 Ma) calc-alkaline volcanism of NE Central Iran, where hornblende-controlled fractionation has been demonstrated. Major element mass balance modeling indicates RFC dominated by a fractionating assemblage made of Hbl_52.0–52.5 + Pl_44.1–44.2 + Ttn_3.3–3.9 (phases are expressed on total crystallized assemblage). REE-FC modeling shows, instead, a lower degree of fractionation with respect to RFC models that is interpreted as due to hornblende and plagioclase resorption by the residual melt. Calculations demonstrate that fractionation of the Tschermak molecule can readily produce dacite and rhyolite magmas starting from a calc-alkaline andesite source (FC = ca. 30 %). In particular, the Tschermak molecule controls both the heavy rare earth elements (HREE) and light rare earth element (LREE) budgets in calc-alkaline differentiation trends.  相似文献   

The effect of surface profile, rock strength and pretension load on bending behaviour of fully grouted bolts     

Hossein Jalalifar  Naj Aziz  Muhammad Hadi 《Geotechnical and Geological Engineering》2006,24(5):1203-1227

Fully encapsulated rock bolting has, in recent years, become a universally accepted system of ground reinforcement in mining and tunnel construction. The application of bolting systems extends both to rebar as well as cable bolting. The effectiveness of the bolt application has been studied in shear, both by laboratory tests as well as by numerical modeling. A specially constructed double shearing apparatus (DSA) was used to examine the shearing behaviour of a bolt installed perpendicularly across two joints. The experimental study was complemented with three-dimensional numerical analysis. Parameters examined include, the effect of reinforced material on tension/compression zones along the sheared bolt, shear resistance, shear displacement and induced strains and stresses during bolt bending process. The study was undertaken at both free load and pretension conditions. The conclusions drawn from the study were the level of bolt resistance to shear was influenced by bolt profile configuration, the strength of the rock or medium influenced the level of load generated on the bolt and the increased bolt pretension contributed to increased shearing load of the bolted medium. The numerical simulation of the bolt/medium interaction and deformational behaviour were found to be in close agreement with the experimental test results.  相似文献   

Bumping against a Gas Ceiling   总被引：1，自引：0，他引：1  

Hadi Dowlatabadi 《Climatic change》2000,46(3):391-407

The adoption of physical thresholds as a ceiling for permitted climate change sidesteps contentious issues such as: policy cost, impact valuation, discounting and equity. In this paper I offer some reflections on the concept of tolerable climate change. I also use an integrated climate assessment model (ICAM-3) to demonstrate how uncertainties in our understanding of socioeconomic and earth systems reduce the probability of success in keeping climate change within a pre-defined tolerable range. Finally, I explore the implications of socioeconomic thresholds for welfare loss in pursuit of a climate policy (e.g., tax rebellions). Crossing such regional socioeconomic thresholds will lead to local failures to pursue climate change mitigation policies — increasing the probability of straying beyond the tolerable window of global climate change. Given various uncertainties and the dynamics of the socioeconomic and the earth systems, the odds of success in staying within a climate change window of T 2°C, and T/yr 0.015°C are estimated to be no higher than 25% over the next century. A risk-risk tradeoff approach appears to hold promise, but while adoption of a larger window of tolerance increases the probability of success, it also opens the window specification criteria to contention.  相似文献   

Ground-motion prediction equations for interface earthquakes of M7 to M9 based on empirical data from Japan     

Hadi Ghofrani  Gail M. Atkinson 《Bulletin of Earthquake Engineering》2014,12(2):549-571

Ground motion prediction equations (GMPEs) have a major impact on seismic hazard estimates, because they control the predicted amplitudes of ground shaking. The prediction of ground-motion amplitudes due to mega-thrust earthquakes in subduction zones has been hampered by a paucity of empirical ground-motion data for the very large magnitudes (moment magnitude (M) $>$ 7) of most interest to hazard analysis. Recent data from Tohoku M9.0 2011 earthquake are important in this regard, as this is the largest well-recorded subduction event, and the only such event with sufficient data to enable a clear separation of the overall source, path and site effects. In this study, we use strong-ground-motion records from the M9 Tohoku event to derive an event-specific GMPE. We then extend this M9 GMPE to represent the shaking from other M $>$ 7 interface events in Japan by adjusting the source term. We focus on events in Japan to reduce ambiguity that results when combining data in different regions having different source, path and site effect attributes. Source levels (adjustment factors) for other Japanese events are determined as the average residuals of ground-motions with respect to the Tohoku GMPE, keeping all other coefficients fixed. The mean residuals (source terms) scale most steeply with magnitude at the lower frequencies; this is in accord with expectations based on overall source-scaling concepts. Interpolating source terms over the magnitude range of 7.0–9.0, we produce a GMPE for large interface events of M7–M9, for NEHRP B/C boundary site conditions (time-averaged shear-wave velocity of 760 m/s over the top 30 m) in both fore-arc and back-arc regions of Japan. We show how these equations may be adjusted to account for the deeper soil profiles (for the same value of $\hbox {V}_\mathrm{S30})$ in western North America. The proposed GMPE predicts lower motions at very long periods, higher motions at short periods, and similar motions at intermediate periods, relative to the simulation-based GMPE model of Atkinson and Macias (2009) for the Cascadia subduction zone.  相似文献   

Magnitude Estimation for the 2011 Tohoku-Oki Earthquake Based on Ground Motion Prediction Equations     

Attieh Eshaghi  Kristy F. Tiampo  Hadi Ghofrani  Gail M. Atkinson 《Pure and Applied Geophysics》2015,172(8):2139-2155

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Applying Optimized Support Vector Regression Models for Prediction of Tunnel Boring Machine Performance     

Hadi Fattahi  Nima Babanouri 《Geotechnical and Geological Engineering》2017,35(5):2205-2217

One of the main factors in the effective application of a tunnel boring machine (TBM) is the ability to accurately estimate the machine performance in order to determine the project costs and schedule. Predicting the TBM performance is a nonlinear and multivariable complex problem. The aim of this study is to predict the performance of TBM using the hybrid of support vector regression (SVR) and the differential evolution algorithm (DE), artificial bee colony algorithm (ABC), and gravitational search algorithm (GSA). The DE, ABC and GSA are combined with the SVR for determining the optimal value of its user defined parameters. The optimization implementation by the DE, ABC and GSA significantly improves the generalization ability of the SVR. The uniaxial compressive strength (UCS), average distance between planes of weakness (DPW), the angle between tunnel axis and the planes of weakness (α), and intact rock brittleness (BI) were considered as the input parameters, while the rate of penetration was the output parameter. The prediction models were applied to the available data given in the literature, and their performance was assessed based on statistical criteria. The results clearly show the superiority of DE when integrated with SVR for optimizing values of its parameters. In addition, the suggested model was compared with the methods previously presented for predicting the TBM penetration rate. The comparative results revealed that the hybrid of DE and SVR yields a robust model which outperforms other models in terms of the higher correlation coefficient and lower mean squared error.  相似文献