Catastrophic movement of rocks and proposed solutions to avoid its risks in the Abu El-Reesh area, northeast Aswan City, Egypt   总被引：1，自引：1，他引：0  

Ashraf Emam  Abdel Hamid S. El-Fakharani  Adel W. Felesteen  Sayed A. Selim  Kamal M. Hafez 《Arabian Journal of Geosciences》2012,5(4):607-616

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.  相似文献   

Groundwater contamination assessment in Al-Quwy’yia area of central Saudi Arabia using transient electromagnetic and 2D electrical resistivity tomography     

Mohamed Metwaly  Eslam Elawadi  Sayed S. R. Moustafa  Nassir Al Arifi  Mohamed El Alfy  EKab Al Zaharani 《Environmental Earth Sciences》2014,71(2):827-835

Groundwater contamination is one of the most significant problems in arid countries. Al-Quwiy’yia region is an example of an area where the groundwater is contaminated as a result of infiltration of waste water in low-lying areas adjacent to inhabited zones. Such contamination poses significant environmental threats for the surrounding environment and groundwater. Surface observations and spatial distribution of contamination observed in the shallow aquifer indicate that the main contamination sources were from sewage as well as from waste water dumping. However, the main source of water supply for the whole area is groundwater abstracted from the relatively shallow aquifer. Therefore, the transient electromagnetic method (TEM) and 2D electrical resistivity tomography (2D ERT) have been applied close to the waste water dump site to characterize the response of pollution plumes. Both of these geoelectrical techniques are sensitive to electrical conductivity as well as to other physical properties, which are greatly influenced by the polluted groundwater. Therefore, it is possible to profile the contamination plumes, both vertically and horizontally, in the vicinity of the measured stations. The ERT profiles gave detailed information about the lateral distribution of the contaminated groundwater, whereas the TEM demonstrated the vertical extensions.  相似文献   

The impact of subsurface geological structure on the groundwater occurrence using geophysical techniques in wadi El Kallabiyyah and wadi As Sabil,East Esna,Eastern Desert,Egypt     

Hosny M. Ezz El Deen  Ahmed N. El Sayed  Mostafa S. M. Barseem 《Arabian Journal of Geosciences》2014,7(6):2151-2163

The present study aims to explain some hydrogeological problems that are related to geological setting in two wadis: El Kallabiyyah and As Sabil East Esna. For this purpose, land magnetic, vertical electrical soundings, and two-dimensional electrical resistivity imaging profiles were measured. The lithological succession comprises Upper Cretaceous to Quaternary deposits that rest on a Precambrian basement rock. The results of the interpretation of the land magnetic measurements in wadi El Kallabiyyah represent the depth to the basement rock which ranges from 260 to 660 m and increases towards the northeast trend, but in wadi As Sabil, there is a large basin at the center of the wadi with the recorded depth to the basement reaching 1,300 m due to the effect of two normal faults (F1 and F2). The results of the interpretation of the vertical electrical sounding and two-dimensional imaging confirmed the presence of these faults in wadi As Sabil. The results of the geoelectrical measurements in wadi El Kallabiyyah represented the water-bearing layer at the third unit that consists of sands, gravels, boulders, and clays. The presence of clay will affect the potentiality of a drilled well. For wadi As Sabil, the results of geoelectrical measurements led to the lower part of the second unit which acts as a water-bearing layer that consists of sands, boulders, gravels, and clays. It can be concluded that the best site for drilling wells in wadi El Kallabiyyah is at vertical electrical sounding no.5 with a total depth of not less than 230 m. In wadi As Sabil, the drilled wells must be concentrated at the center and the downstream.  相似文献   

Application of spectral analysis technique on ground magnetic data to calculate the Curie depth point of the eastern shore of the Gulf of Suez,Egypt     

El Sayed Ibrahim Selim  Essam Aboud 《Arabian Journal of Geosciences》2014,7(5):1749-1762

The bottom of the magnetized crust determined from the spectral analysis of magnetic anomaly is interpreted as a level of the Curie point isotherm. A spectral analysis technique was used to estimate the depth of the magnetic anomalies sources (Curie point depth analysis) of the eastern shore of the Gulf of Suez, Egypt. The depth to the tops and centers of the magnetic anomalies are calculated by azimuthally averaged power spectrum method for the whole area. The results obtained suggests from this study showed that the average depth to the top of the crustal block ranges between 1.15 and 1.9 km, whereas the average depth to the center of the deepest crustal block ranges between 9.1 and 12.7 km. Curie point depths in the study area range between 14.5 km in the northwestern part of the study area and 26 km in the southeastern part of the study area. The results imply a high geothermal gradient (34.7 °C/km) and corresponding high heat flow value (72.87 mW/m²) in the northwestern part of the study area. The southeastern part of the study area displays a low geothermal gradient (24.26 °C/km) and low heat flow value (50.9 mW/m²). These results are consistent with the existence of the possible promising geothermal reservoir in the eastern shore of the Gulf of Suez especially at Hammam Faraun area.  相似文献