Geophysical survey for geological hazards assessment of Wadi Thuwal area, KSA: a case history     

Mansour A. Al-Garni  Mohamed G. El-Behiry  Mohamed M. Gobashy 《Arabian Journal of Geosciences》2012,5(1):133-146

Magnetic and seismic methods have been used in this study as complementary methods to each other to construct a geologic hazard map for Wadi Thuwal area. Magnetic interpretation for deep-seated geologic structures has involved reduction to pole algorithm and downward continuation techniques. It showed that there are three major fault trends: NE-SW and NNE-SSW, NW-SE, and N-S. Furthermore, shear zone has been found close to Harrat Thuwal, which was confirmed by the seismic method. Seismic method revealed three lithologic layers where the depth of the bedrock was found to be ranging between 9?m at the southeastern part of the study area and 24?m at its northern part. It showed also five major fault trends: NW-SE, ENE-WSW, NE-SW, and nearly E-W. Supported by the surface geology, magnetic and seismic results showed that the Wadi Thuwal area can be divided into three zones on the basis of geologic hazards, depending on the presence of geologic features such as faults. It is recommended that before any development plan in Wadi Thuwal area, the delineated hazard zonation should be taken into account.  相似文献   

Hartley spectral analysis of self-potential anomalies caused by a 2-D horizontal circular cylinder     

Mansour A. Al-Garni  Narasimman Sundararajan 《Arabian Journal of Geosciences》2012,5(6):1341-1346

The real spectral analysis of SP anomalies due to 2-D horizontal circular cylinder is carried out using Hartley transform. The Hartley transform is an alternate means of realizing spectral analysis in real domain unlike the Fourier spectral analysis. The Hartley transform yields a straightforward interpretation of SP anomalies caused by horizontal circular cylinder wherein all the parameters are derived independently as a function of frequency. A theoretical example illustrates the procedure. The effect of random noise, up to 10% of white Gaussian noise, on the interpretation scheme was also studied and found to be of negligible. The field example of the ??Sulleymonkey?? anomaly in the Ergoni copper district, Turkey exemplifies the applicability of the proposed method.  相似文献   

An improvement in mass flux convective parameterizations and its impact on seasonal simulations using a coupled model     

Elsayed Yousef  Ahmed  Ehsan  M. Azhar  Almazroui  Mansour  Assiri  Mazen E.  Al-Khalaf  Abdulrahman K. 《Theoretical and Applied Climatology》2017,127(3-4):779-791

A new closure and a modified detrainment for the simplified Arakawa–Schubert (SAS) cumulus parameterization scheme are proposed. In the modified convective scheme which is named as King Abdulaziz University (KAU) scheme, the closure depends on both the buoyancy force and the environment mean relative humidity. A lateral entrainment rate varying with environment relative humidity is proposed and tends to suppress convection in a dry atmosphere. The detrainment rate also varies with environment relative humidity. The KAU scheme has been tested in a single column model (SCM) and implemented in a coupled global climate model (CGCM). Increased coupling between environment and clouds in the KAU scheme results in improved sensitivity of the depth and strength of convection to environmental humidity compared to the original SAS scheme. The new scheme improves precipitation simulation with better representations of moisture and temperature especially during suppressed convection periods. The KAU scheme implemented in the Seoul National University (SNU) CGCM shows improved precipitation over the tropics. The simulated precipitation pattern over the Arabian Peninsula and Northeast African region is also improved.

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Climatology of the 500-hPa mediterranean storms associated with Saudi Arabia wet season precipitation     

Mansour Almazroui  S. Kamil  K. Ammar  Kevin Keay  A. O. Alamoudi 《Climate Dynamics》2016,47(9-10):3029-3042

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Groundwater recharge to ophiolite aquifer in North Oman: constrained by stable isotopes and geochemistry     

Osman Abdalla  Rashid Al Abri  Khadija Semhi  Talal Al Hosni  Mansour Amerjeed  Ian Clark 《Environmental Earth Sciences》2016,75(15):1117

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Aeromagnetic data interpretation of east Qattara Depression,Northwest Desert,Egypt     

Mansour A. Al-Garni 《Arabian Journal of Geosciences》2018,11(6):133

The study area is located at the east of Qattara Depression at the north of the Western Desert of Egypt. The study area contains Abu Gharadig basin, which is the most petroliferous basin in the Egyptian Western Desert. Only three exploratory wells are presented in the study area, showing a thick sediment section overlying basement rocks. Magnetic data have been frequently used in geophysical exploration. Aeromagnetic data are mainly utilized to estimate the depth to the magnetic basement as well as to delineate the possible structures of the study area. The depth to magnetic basement has been estimated using the analytical solution of exponential equations obtained from the Fourier transformation of magnetic data, assuming multi-prisms. The depths obtained from this technique vary from 0.70 to 2.91 km with an average depth of 2.08 km. Local phase filters have been mainly used as edges detector where the possible occurrences structures can be delineated. Hyperbolic tilt angle, second-order tilt angle, and normalized total horizontal derivative (TDX) provide the best results for delineating the possible structures, showing the possible contacts within the basement of the study area. The edge enhancement filters show that the study area has been affected by different structural trends taking E-W, NE-SW, NNE-SSW, N-S, and ENE-WSW directions.  相似文献   

CAD-DRASTIC: chloride application density combined with DRASTIC for assessing groundwater vulnerability to road salt application     

Mansour Salek  Jana Levison  Beth Parker  Bahram Gharabaghi 《Hydrogeology Journal》2018,26(7):2379-2393

Road salt is pervasively used throughout Canada and in other cold regions during winter. For cities relying exclusively on groundwater, it is important to plan and minimize the application of salt accordingly to mitigate the adverse effects of high chloride concentrations in water supply aquifers. The use of geospatial data (road network, land use, Quaternary and bedrock geology, average annual recharge, water-table depth, soil distribution, topography) in the DRASTIC methodology provides an efficient way of distinguishing salt-vulnerable areas associated with groundwater supply wells, to aid in the implementation of appropriate management practices for road salt application in urban areas. This research presents a GIS-based methodology to accomplish a vulnerability analysis for 12 municipal water supply wells within the City of Guelph, Ontario, Canada. The chloride application density (CAD) value at each supply well is calculated and related to the measured groundwater chloride concentrations and further combined with soil media and aquifer vadose- and saturated-zone properties used in DRASTIC. This combined approach, CAD-DRASTIC, is more accurate than existing groundwater vulnerability mapping methods and can be used by municipalities and other water managers to further improve groundwater protection related to road salt application.  相似文献   

Unsteady magnetohydrodynamic flow through a porous medium between two infinite parallel plates     

I. A. Hassanien  M. A. Mansour 《Astrophysics and Space Science》1990,163(2):241-246

An analysis of a two-dimensional unsteady flow of a viscous, incompressible electrically-conducting fluid through a porous medium bounded by two infinite parallel plates under the action of a transverse magnetic field is presented. The lower plate is fixed while the other is oscillating in its own plane. Expressions for the transient velocity, the amplitude, the phase angle, and the skin-friction are derived. The effects of the magnetic parameters, permeability of the porous medium, and the frequency parameter are discussed.  相似文献   

Découverte d''une frayère de poissons téléosteens dans des diatomites messiniennes du Djebel Murdjadjo (environs d''Oran, Algérie)     

Jean Gaudant  Jean-Paul Saint-Martin  Mostefa Bessedik  Bouhameur Mansour  Pierre Moissette  Jean-Marie Rouchy 《Journal of African Earth Sciences》1997,24(4):511-529

A new locality of Messinian fossil fish has been found in the diatomite outcropping in the surroundings of the former “Ferme Giraud”, in the Murdjadjo Massif (near Oran, Algeria). It has yielded an oligospecific fish fauna, including five species indicative of a littoral marine environment that may have occurred in a gulf bottom. This was probably linked to a brackish lagoon, as indicated by the diatom flora.  相似文献   

Hematite grains: Size and coercive force from AF demagnetization at high temperatures     

Mohamad Mansour Bina  Michel Prévot 《Physics of the Earth and Planetary Interiors》1977,13(4):272-275

The coercivity spectrum of low-field high-temperature partial thermoremanent magnetization (PTRM) of a synthetic hematite powder, extremely high at room temperature, decreases very slowly with increasing temperature up to 500°C then decreases rapidly, especially above 600°C. From the AF demagnetization curves at 600 and 650°C it is calculated, following the Néel's theory of single-domain particles that the grains carrying the PTRM have a mean coercive force of 23 ± 5 kOe and a mean grain size of 0.40 ± 0.15 μm, which is not significantly different from the mean grain size of 0.48 ± 0.03 μm from electron micrograph observations.  相似文献