Spatial and temporal analysis of the drought vulnerability and risks over eight decades in a semi-arid region (Tensift basin: Morocco)

Theoretical and Applied Climatology - The multiple downscaled scenario products allow us to assess the uncertainty of the variations of precipitation and temperature in the current and future...     

Faulting and fracturing in the Jurassic carbonate ramp folds of southern Rif ridges (Northern Morocco)

In the South Rifian ridges (SRR), the dominated structures correspond to the faulted anticline characteristic of a foreland orogeny context, front of the Rif Alpine belt. These anticlines correspond to thrust propagation folds. Geometric model of these structures shows that the normal faults have controlled the Mesozoic sedimentation during extensive episodes and participated in determining areas of thrusting during Miocene compressional phases. However, the normal fault strike which is relative to the direction of the shortening determined the geometry of diverse folds whether into the frontal ramps, lateral, or oblique. In the meantime, the systematic fracturing study in the Jurassic limestone beds, in different parts of the folds with axes oriented E-W, NW-SE, and NE-SW, permits to propose a relative fracturing chronology and tries investigating the relationship between folding and fracturing. The three main fracture families, oblique, transversal, and axial, appear simultaneously during the amplification of the fold. The simple shear in the limb contributes the latest to the folding reactivation and the density of the intensification of these microfractures. Likewise, given the important downslope fold limb dip of the ramp propagation folds, theoretically the shear intensity is more important, and micro-fractures are more important in the downslope fold limb, thus the uphill one.     

Economic evaluation of using marine dredged material for erosion control along the northeast coast of the Nile Delta,Egypt

The present study is the first attempt in Egypt to assess feasibility of using of dredging material from Damietta Harbor in the northwestern Nile Delta for erosion control. The study also provides an economic evaluation for the shoreline management alternatives selected to mitigate for the effects of coastal erosion at two pilot eroding areas (namely, A and B) located near the Damietta Harbor. Results of compatibility analysis reveal that the dredging material is fairly compatible with the native sand of the nearby eroding beaches. In addition to soft nourishment by dredged sand, other types of coastal engineering measures which are often used in erosion management area were also evaluated as alternatives for erosion control and mitigation solution. Economic feasibility assessment by means of cost-benefit analysis of direct and indirect items has been carried out to facilitate comparison between these alternatives. Analysis of alternatives has been also supported by other criteria to select the cost-effective and environmentally acceptable option to protect the eroding pilot areas. These criteria include the high total cost paid for maintenance of the Damietta Harbor channel with no use, anticipated impacts on the littoral system, sustainability, future plans for protection of the existing coastlines, and lessons learned from previous shore protection works in the Nile Delta. The final selection of the best viable alternative indicates that the procedure of beach nourishment is the most appropriate form for protection area A, while a combination of groins and sand nourishment is more relevant for area B. In any case, material dredged from the navigation approach of the Damietta Harbor should be utilized as a borrow material in the nourishment schemes and excluding use of the terrestrial sources.     

Study the feasibility of using PPP for establishing CORS network

Nowadays many continuously operating reference stations (CORS) network were established in Middle East to improve the surveying tasks. Establishing such geodetic control networks can be a costly business where multiple stations should be occupied simultaneously and post-processed with scientific software. Recently, precise point positioning (PPP) provides precise positioning values that may be an alternative to precise relative processing. The current research aims to investigate that PPP has a potential as a reliable absolute positioning technique operational simplicity as well as to investigate the capability of PPP approach to be a low cost alternative to the conventional positioning methods used in position determination of core networks stations. In comparison with common relative GPS techniques, the costs are reduced; because no base stations and no simultaneous observations are necessary, no need for control network maintenance which could be the most defective factors that Egypt HARN network suffered from. To see the feasibility study of using PPP for precise determination of the CORS, 14 days of GNSS data for the 14 Kuwait integrated with 27 IGS stations were processed by Bernese software to calculate the precise coordinates of Kuwaiti CORS network in the latest terrestrial geodetic frame. Three days of these data were processed by Trimble business center software and using PPP approach to calculate the precise coordinates of Kuwait network. In the current research, a comparable investigation was carried out between the coordinates obtained from Bernese software, Trimble business center, and PPP approach. The comparison proved high level of agreement between the coordinates which confirm that PPP approach can be applied for establishment of CORS network.     

Local site effects estimated from ambient vibration measurements at the Nubian habitations area in Kurkur,Aswan, Egypt

The Egyptian government proposed a general plan, aiming to construct new settlements for Nubians in south Aswan in different places around Nasser’s Lake, one of these settlements in Kurkur area. This area are affecting by near distance earthquakes from Kalabsha faults system. These earthquakes generated great site effects on the sedimentary layers that in turn significantly influenced earthquake ground motions in the area. The main objective of the current study is to estimate the effect of local geology on seismic motion in terms of fundamental resonance frequency (f₀) and the corresponding H/V amplitude values (A₀) using the Nakamura technique. Ambient vibration measurements were carried out at 40 sites that are representative for the different geological units beneath the area. The recorded signals were processed using the horizontal-to-vertical (H/V) spectral ratio Nakamura’s technique. Analysis of spatial distribution of the fundamental frequencies (f₀) and the corresponding H/V amplitudes (A₀) showed that the f₀ value varies from 0.98 to 2.74 Hz, while A₀ varies from 2.2 to 6.6 within the study area. Output of this study is very important for solving the problems, which associated with the construction of various civil engineering purposes, for land-use planning and for earthquakes resistant structure design.     

Strength and Stiffness Properties of Green Lightweight Fill Mixtures

Approximately 250 million tires are discarded each year in the United States and 20 million in Canada. Finding sustainable ways to dispose these tires continues to be a problem throughout the world not only in North America. Disposal issues along with a continuing increase in tire production have resulted in an increase in tire stockpiles, 30 % of these tires end up occupying valuable landfill space. Tire Derived Aggregates (TDA) made from scrap tires have a compacted dry unit weight of 6.9 kN/m³ and a specific gravity of 1.06 making their use as lightweight fill material especially for highway embankments over soft soils very advantageous. Using TDA as fill material not only provide a new construction material but also help to provide sustainable solution for several environmental and economic problems. Previous studies have shown that the addition of Tire Derived Aggregates (TDA) to sand results in a fill material which is characterized by its higher shear strength compared to that of 100 % sand. While there have been several studies investigating various properties and situations involving TDA’s, there remain areas that still require exploration. The effect of soil/aggregate gradation on shear strength is one of particular interest. All of the research conducted to date investigated only the sand gradation mixed with uniform TDA gradation. None of the conducted research investigated the interaction between the gradation of the two materials and its effect on the performance of the fill mixture. The main goal of this paper is to gain an understanding of this interaction in aim of producing better fill mixtures with enhanced characteristics.     

Application of kinematic vorticity and gold mineralization for the wall rock alterations of shear zone at Dungash gold mining,Central Eastern Desert,Egypt

The use of porphyroclasts rotating in a flowing matrix to estimate mean kinematic vorticity number (Wm) is important for quantifying the relative contributions of pure and simple shear in wall rocks alterations of shear zone at Dungash gold mine. Furthermore, it shows the relationship between the gold mineralization and deformation and also detects the orientation of rigid objects during progressive deformation. The Dungash gold mine area is situated in an EW-trending quartz vein along a shear zone in metavolcanic and metasedimentary host rocks in the Eastern Desert of Egypt. These rocks are associated with the major geologic structures which are attributed to various deformational stages of the Neoproterozoic basement rocks. We conclude that finite strain in the deformed rocks is of the same order of magnitude for all units of metavolcano-sedimentary rocks. The kinematic vorticity number for the metavolcanic and metasedimentary samples in the Dungash area range from 0.80 to 0.92, and together with the strain data suggest deviations from simple shear. It is concluded that nappe stacking occurred early during the underthrusting event probably by brittle imbrication and that ductile strain was superimposed on the nappe structure during thrusting. Furthermore, we conclude that disseminated mineralization, chloritization, carbonatization and silicification of the wall rocks are associated with fluids migrating along shearing, fracturing and foliation of the metamorphosed wall rocks.     

Rapid analysis of risk assessment using developed simulation of chemical industrial accidents software package

The environmental consequences are defined as consequences of accidental release of hazardous substances to the natural environment. This release can lead to many hazards depending on the material stored. The consequences of these hazards to the environment are widespread and have significant importance to human communities living in the surroundings. The mathematical models are extremely useful tools to predict the impacts of chemical process accidents. The objective of this paper is to develop a software package for accident simulation and damage potential estimation. The software is coded in visual basic and is compatible with windows working environments. The software is called Simulation of chemical industrial accident. This application is a comprehensive software package which can be integrated with geographical information system to predict and display the consequence of chemical hazards. The software is a user-friendly and effective tool for evaluating the consequences of major chemical accidents, process decision making for land-use planning, namely locating suitable hazardous installations, hazardous waste disposal areas and emergency response plan.