Assessment of subsurface structural elements around greater Cairo by using integrated geophysical tools     

Sultan Awad Sultan Araffa  Fernando A. Monteiro Santos  Tarek Arafa-Hamed 《Environmental Earth Sciences》2014,71(8):3293-3305

Geophysical techniques such as gravity, magnetic and seismology are perfect tools for detecting subsurface structures of local, regional as well as of global scales. The study of the earthquake records can be used for differentiating the active and non-active fault elements. In the current study, more than 2,200 land magnetic stations have been measured using two proton magnetometers. The data are corrected for diurnal variations and then reduced by the International Geomagnetic Reference Field. The corrected data have been interpreted by different techniques after filtering the data to separate shallow sources (basaltic sheet) from the deep sources (basement complex). Both Euler deconvolution and 3-D magnetic modeling were carried out. The results of interpretation indicate that the depth to the upper surface of basaltic sheet ranges from <10 to 600 m, depth to the lower surface ranges from 60 to 750 m, while the thickness of the basaltic sheet varies from <10 to 450 m. Moreover, gravity measurements are conducted at 2,250 stations using a CG-3 gravimeter. The measured values are corrected to construct a Bouger anomaly map. The least squares technique is then applied for regional–residual separation. The third order of least squares is found to be the most suitable to separate the residual anomalies from the regional one. The resultant third-order residual gravity map is used to delineate the structural fault systems of different characteristic trends. The trends show an NW–SE trend parallel to that of Gulf of Suez, an NE–SW trend parallel to the Gulf of Aqaba and an E–W trend parallel to that of the Mediterranean Sea. Taking seismological records into consideration, it is found that most of the 24 earthquake events recorded in the study area are located on fault elements. This gives an indication that the delineated fault elements are active.  相似文献   

Landscape and a political border determine desert arthropods distribution     

U. Shanas  Y.A. GalyunM. Alshamlih  J. CnaaniD. Guscio  F. KhouryS. Mittler  K. NassarI. Shapira  D. SimonH. Sultan  E. Topel  Y. Ziv 《Journal of Arid Environments》2011,75(3):284-289

We studied the distribution of arthropods in the Arava desert on both sides of the Israeli-Jordanian border, to assess the impact of different anthropogenic pressures on the local fauna. We examined how different landscape units, proximity to agricultural fields, and human societies, might affect the diversity of ground dwelling beetles, and spiders, using ordination and diversity estimation methods. Our results suggest that although both countries contain similar habitats, each has its own unique characteristics, probably due to different cultural practices. The immediate repercussion is that loss of a habitat on one side of the border cannot be compensated with preservation of the same habitat across the border, due to fauna dissimilarity. For example, beetle species can be assembled according to landscape units, but within each landscape unit they show dissimilarities that are based on the geopolitical location. Spiders fail to assemble according to landscape units but cluster as a unique group within Israel. Both landscape unit type and the border, were found to be important for the overall species diversity of this ecosystem and therefore “redundancy” should be carefully applied, especially across geopolitical borders.  相似文献   

Quantifying the role of sandy–silty sediments in generating slope failures during earthquakes: example from the Algerian margin     

Gabriela Dan  Nabil Sultan  Bruno Savoye  Jacques Deverchere  Karim Yelles 《International Journal of Earth Sciences》2009,98(4):769-789

The Algerian margin is a seismically active region, where during the last century, several large magnitude earthquakes took place. This study combines geotechnical and sedimentological data with numerical modelling to quantitatively assess the present-day slope stability of the Algerian margin. Geotechnical laboratory tests, such as cyclic triaxial tests, oedometric tests and vane shear tests were carried out on sediment cores collected on the study area. The liquefaction potential of a sediment column located about 30 km from the Boumerdès earthquake epicentre of 21st May 2003 was evaluated theoretically for an earthquake of M _w  = 6.8. We show that thin sand and silt beds such as those described on recovered sediment cores are the main cause of sediment deformation and liquefaction during earthquakes. Numerical calculations showed that the slope failure may occur during an earthquake characterised by a PGA in excess of 0.1g, and also that, under a PGA of 0.2g liquefaction could be triggered in shallow silty–sandy deposits. Moreover, comparison of the predicted slope failure with failure geometries inferred from seafloor morphology showed that earthquakes and subsequent mass movements could explain the present-day morphology of the study area.  相似文献   

Joint inversion of gravity and geoelectrical data for groundwater and structural investigation: application to the northwestern part of Sinai, Egypt   总被引：2，自引：0，他引：2  

F. A. Monteiro Santos  S. A. Sultan  Patrícia Represas  A. L. El Sorady 《Geophysical Journal International》2006,165(3):705-718

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Sensitivity studies and stochastic optimization of CO2 foam flooding     

Najmudeen Sibaweihi  Abeeb A. Awotunde  Abdulla S. Sultan  Hasan Y. Al-Yousef 《Computational Geosciences》2015,19(1):31-47

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Redefining homogeneous climate regions in Bangladesh using multivariate clustering approaches     

Mahmud  Sultan  Sumana  Ferdausi Mahojabin  Mohsin  Md  Khan  Md. Hasinur Rahaman 《Natural Hazards》2022,111(2):1863-1884

Natural Hazards - The knowledge of the climate pattern for a particular region is important for taking appropriate actions to alleviate the impact of climate change. It is also equally important...  相似文献   

Trace element soil contamination from smelters in the Illawarra region,New South Wales,Australia     

Jafari  Yasaman  Jones  Brian G.  Pacheco  Joanna C.  Umoru  Sultan 《Environmental Earth Sciences》2020,79(15):1-11

Boundaries of densely populated areas can approach with time to old subsurface repositories of radioactive waste due to growth of settlement territories. P  相似文献   

Lung function in subjects exposed to crude oil spill into sea water     

Meo SA  Al-Drees AM  Meo IM  Al-Saadi MM  Azeem MA 《Marine pollution bulletin》2008,56(1):88-94

A Greek oil-tanker ran aground, resulting in a huge oil spill along the costal areas of Karachi, Pakistan. The purpose of this study was to assess the lung function and follow up change after one year in subjects exposed to crude oil spill in sea water. It was a cross sectional study with follow up in 20 apparently healthy, non-smoking, male workers, who were exposed to a crude oil spill environment during oil cleaning operation. The exposed group was matched with 31 apparently healthy male control subjects. Pulmonary function test was performed using an electronic Spirometer. Subjects exposed to polluted air have significant reduction in forced vital capacity (FVC), forced expiratory volume in first second (FEV(1)), forced expiratory flow (FEF(25-75%)) and maximum voluntary ventilation (MVV) compared to their matched controls. This impairment was reversible and lung functions parameters were improved when the subjects were withdrawn from the polluted air environment.  相似文献   

A stable flat universe with variable cosmological constant in f(R,T) gravity     

Nasr Ahmed  Sultan Z.Alamri 《天文和天体物理学研究(英文版)》2018,(10)

In this paper, a general FRW cosmological model has been constructed in f(R,T) gravity reconstruction with variable cosmological constant. A number of solutions to the field equations has been generated by utilizing a form for the Hubble parameter that leads to Berman's law of constant deceleration parameter q = m-1. The possible decelerating and accelerating solutions have been investigated. For(q 0) we get a stable flat decelerating radiation-dominated universe at q = 1. For(q 0) we get a stable accelerating solution describing a flat universe with positive energy density and negative cosmological constant. Nonconventional mechanisms that are expected to address the late-time acceleration with negative cosmological constant have been discussed.  相似文献   

Biodegradation of crude oil and n-alkanes by fungi isolated from Oman     

Elshafie A  AlKindi AY  Al-Busaidi S  Bakheit C  Albahry SN 《Marine pollution bulletin》2007,54(11):1692-1696

Ten fungal species isolated from tar balls collected from the beaches of Oman were tested for their abilities to grow and degrade n-alkanes and crude oil. The abilities of Aspergillus niger, A. ochraceus and Penicillium chrysogenum to degrade n-alkanes (C13-C18), crude oil were compared and their mycelial biomass was measured. Significant differences were found in the utilization of C15, C16, C17 and C18 by the three fungi. Similarly, significant differences we found in the amount of biomass produced by the three fungi growing on C13, C17, C18 and crude oil. The correlation coefficient of biomass and oil utilization was not statistically significant for Aspergillus niger, significant for Aspergillus terreus and highly significant for P. chrysogenum.  相似文献