Rock slope stability and design in Arafat–Muzdalifa area,Saudi Arabia

The present contribution is a complete study extending before, during, and after the excavation of the mountain side that lying north of road 7. It includes slope stability analysis, rock cut design, and rockfall modeling for natural slope and rock cut face. Neoproterozoic granodiorite and biotite granite forming the slope body have medium to very high strengths. Mineral compositions and textures of these intact rocks control the strength values. These rocks are intensively dissected by fractures that are filled with montmorillonite and chlorite. The high plasticity and slippery nature of these filling materials represent the main problem that may face a rock cut designer because they damage the mechanical properties of these fractures. The problem begins with the selection of the rock mass classification that deals with the fracture fillings and extends during the stability analysis and the suggestion of mitigation and supporting measures. The rock masses building the natural slope are suffered by plane, wedge, and toppling failures. Therefore, two rock cut designs are suggested to avoid the hazards related to these failures and considering the construction cost as well. Rockfall modeling for the natural slope and rock cut designs was done to assess the hazards related to these falling of the blocks. The kinetic energy of falling blocks is represented on the roadway by the coverage distance and block rebound amplitude. Slope height has a positive effect on the values of these distance and amplitude, whereas the steepness of berm height has a negative effect on them. Coverage distance is a function to the location of rockfall barrier and to the width of road ditch, while the amplitude controls the barrier height.     

Aquatic macrophyte distribution in Lake Manzala,Egypt

The macrophyte distribution of Lake Manzala is described in relation to water depth, salinity, dissolved oxygen, pH, Cl^–, NO ₃ ^– and PO ₄ ^3– . Changes in species composition of macrophytes are visualised by means of multivariate analysis. The TWINSPAN classification and CANOCO ordination programs (DCA & CCA) were used to analyse the data set. The classification of 100 stands revealed 8 vegetation groups which indicated eleven dominant communities. These arePhragmites australis, Typha domingensis, Scirpus maritimus, Echinochloa stagnina and Ludwigia stolonifera as emergent hydrophytes;Eichhornia crassipes andAzolla filiculoides as floating hydrophytes. The dominant submerged hydrophytes arePotamogeton pectinatus, Najas armata, Ceratophyllum demersum andRuppia maritima. The northern part of the lake with low depth and relatively high salinity has low species diversity (mainly emergent species). Species diversity increases with decreasing salinity and increasing eutrophication near the mouths of the drains in the western and southern parts of the lake. The recent changes in species distribution can be attributed to the effects of salinity, water depth and drainage water. A checklist of macrophytes in the lake is appended.     

Utilization of ASTER and OLI data for lithological mapping of Nugrus-Hafafit area,South Eastern Desert of Egypt

Lithological discrimination of Neoproterozoic rocks occupying Nugrus-Hafafit area, South Eastern Desert of Egypt, has been carried out using Operational Land Imager (OLI) and Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) sensors’ imagery data. The applicable processing enhancement techniques include optimum index factor (OIF), band ratioing, principal component analysis (PCA), and minimum noise fraction (MNF) transform. The area comprises varieties of low-grade metamorphosed ophiolitic mélange and island-arc rocks, thrusting over high-grade metamorphic gneissic core complexes, and intruded by syn-, late-, and post-tectonic granitoids. The OLI band ratio 6/7 discriminates clearly the ophiolitic serpentinites-talc-carbonate rocks, while 4/5 ratio image is able to separate between mafic and felsic rocks. Moreover, the ASTER band ratio 6/8 is used to distinguish the amphibole-bearing rocks, including amphibolite and hornblende gneiss. The OLI and ASTER second principal component (PC2) images reflect the contrast spectral behavior of ophiolitic mélange rocks through visible-near-infrared (VNIR) and shortwave (SWIR) regions. The OLI-PC3 shows the ability to delineate the Fe-rich rocks, including amphibolite and metamafics, while ASTER-PC3 is effective for quartz-feldspathic granites and psammitic gneisses. Visual interpretation and integration of processed data with petrography and field investigation resulted in complete differentiation for the different lithologies and creation of a new detailed geological map of Nugrus-Hafafit area.     

Tectonic Evolution of the Polydeformed Urf Al-Mahib Belt,South-Eastern Desert,Egypt

Geotectonics - The Urf Al-Mahib area, located to the southern part of the Eastern Desert (SED) of Egypt, is covered mainly by juvenile Neoproterozoic crust and Nubian sandstones. Field...     

Brittle normal faulting in the highest-grade Sambagawa metamorphic rocks of central Shikoku, southwest Japan: Indication of the exhumation into the upper crustal level

Analysis of fault system in the high-P/T type Sambagawa metamorphic rocks of central Shikoku, southwest Japan, shows that conjugate normal faults pervasively developed in the highest-grade biotite zone (upper structural level) in three study areas (Asemi river, Oriu and Niihama areas). These conjugate normal faults consist of NE–SW to E–W striking and moderately north-dipping (set A), and NNW–SSE striking and moderately east dipping (set B) faults. The fault set A is dominant compared to the fault set B, and hence most of deformation is accommodated by the fault set A, leading to non-coaxial deformation. The sense of shear is inferred to be a top-to-the-WNW to NNW, based on the orientations of striation or quartz slickenfibre and dominant north-side down normal displacement. These transport direction by normal faulting is significantly different from that at D₁ penetrative ductile flow (i.e. top-to-the-W to WNW). It has also been found that these conjugate normal faults are openly folded during the D₃ phase about the axes trending NW–SE to E–W and plunging west at low-angles or horizontally, indicating that normal faulting occurred at the D₂ phase. D₂ normal faults, along which actinolite breccia derived from serpentinite by metasomatism sometimes occurs, perhaps formed under subgreenschist conditions (ca. 250 °C) in relation to the final exhumation of Sambagawa metamorphic rocks into the upper crustal level. The pervasive development of D₂ normal faults in the upper structural level suggests that the final exhumation of Sambagawa metamorphic rocks could be caused by “distributed extension and normal faulting (removal of overburden)” in the upper crust.     

Improvement of MEMS-IMU/GPS performance using fuzzy modeling

Performance improvement of integrated Inertial Measurement Units (IMU) utilizing micro-electro-mechanical-sensors (MEMS) and GPS is described in this paper. An offline pre-defined Fuzzy model is employed to improve the system performance. The Fuzzy model is used to predict the position and velocity errors, which are the inputs to a Kalman Filter (KF) during GPS signal outages. The proposed model has been verified on real MEMS inertial data collected in a land vehicle test. A number of 30-s GPS outages were simulated during the data processing at different times and under different vehicle dynamics. Performance of the suggested Fuzzy model was compared to that of the traditional KF particularly during the simulated GPS outages. The test results indicate that the proposed Fuzzy model can efficiently compensate for GPS updates during short outages.     

Flood susceptibility prediction using four machine learning techniques and comparison of their performance at Wadi Qena Basin,Egypt

Natural Hazards - Floods represent catastrophic environmental hazards that have a significant impact on the environment and human life and their activities. Environmental and water management in...     

Prediction of Solar Activity Based on Neuro-Fuzzy Modeling

This paper presents an application of the neuro-fuzzy modeling to analyze the time series of solar activity, as measured through the relative Wolf number. The neuro-fuzzy structure is optimized based on the linear adapted genetic algorithm with controlling population size (LAGA-POP). Initially, the dimension of the time series characteristic attractor is obtained based on the smallest regularity criterion (RC) and the neuro-fuzzy model. Then the performance of the proposed approach, in forecasting yearly sunspot numbers, is favorably compared to that of other published methods. Finally, a comparison predictions for the remaining part of the 22nd and the whole 23rd cycle of the solar activity are presented.     

Catastrophic movement of rocks and proposed solutions to avoid its risks in the Abu El-Reesh area, northeast Aswan City, Egypt

Catastrophic mass movement of rocks and torrents affected the Abu El-Reesh area, northeast of Aswan City. The present article aims to evaluate the potential catastrophic movement of rocks, delineate the risk zones, and suggest suitable solutions to avoid the potential risks in this area. The sedimentary succession of Abu El-Reesh area is mainly represented by the Nubian sandstone sequence of Upper Cretaceous (up to 60?m thick) forming a huge scarp at the eastern border of the study area. This sequence comprises two vertically successive rock formations: Timsah Shale Formation and Umm Barmil Sandstone Formation. The Timsah Shale Formation forms the lower part of the sedimentary succession with a thickness of 6?C40?m. It is composed of shale beds with intercalations of sandstones, siltstones, and mudstones. This formation is overlain by the Umm Barmil Sandstone Formation, representing the cap rock of the succession, with a thickness of 4?C20?m. The western scarp face has an irregular concave slope, with slope angles ranging from 22° to 46° in the lower part of scarp and become steep (60°?C86°) at its upper part. The drainage patterns are mainly coarse dendritic and discharge into the Nile River, passing through densely populated zones. These zones are exposed to the torrents during rare rainfall events. Three sets of vertical joints (trending NNW, NNE, and WNW) dissect the cap rocks and intersect with the horizontal bedding planes to form separated cubes and polygonal blocks. Potential catastrophic movement of rocks in Abu El-Reesh area is related to several reasons, including: existence of competent sandstones underlain by incompetent shales, dissection of the coherent cap rock due to intersection of vertical joint sets and bedding planes, presence of exposures with steep slopes, rainfall, and human activities (mining works, sewage water, and irrigation). Based on the dominance of either one or more of these reasons, three subareas (El-Khalasab, El-Shadeeda and El-Aqaba) represent the main risk zones, subjected to rock movements and torrents in the study area. Several solutions have been suggested for avoiding the risks related to the potential catastrophic movement of the rocks and torrents in the study area. The fractured rock masses at the top of scarp should be released either mechanically or manually. All buildings that were built on the slope surface of the scarp should be removed. Also, buildings which were constructed in the inlets of wadis and through the rain spillways should be removed. An unsafe boundary separating safe building borders from unsafe zone (with average width 50?m from the base of scarp) is delineated. As a result, resettlement for people living in this unsafe zone should be transferred to another safe area.