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1.
A scored lithological map including 10 radiometric units is established through applying factor analysis approach to aerial spectrometric data of Area-1, Syrian desert, which includes Ur, eU, eTh, K%, eU/eTh, eU/K%, and eTh/K%. A model of four rotated factors F1, F2, F3, and F4 is adapted for representing 234,829 data measured points in Area-1, where 86% of total data variance is interpreted. A geological scored pseudo-section derived from the lithological scored map is established and analyzed in order to show the possible stratigraphic and structural traps for uranium occurrences associated with phosphate deposits in the studied Area-1. These identified traps presented in this paper need detailed investigation and must be necessarily followed and checked by ground validations and subsurface well logging, in order to locate the anomalous uranium occurrences and explore with more confidence and certitude their characteristics as a function of depth. 相似文献
2.
The Khanaser Valley was geoelectrically thoroughly surveyed through a grid which consisted of twelve VES profiles. The tectonically-oriented
Pichgin and Habibullaev method was enhanced to be applicable in areas of rugged relief and topography. The enhanced profiles
were tectonically interpreted and subsurface structures within the Khanaser Valley were delineated. Accordingly, a tectonic
evolutional scenario of the valley was established and its hydrogeological characteristics were derived. An approach for groundwater
exploration in areas of prominent relief and topography in dry areas such as the Khanaser Valley was established and its validity
was estimated. 相似文献
3.
Jamal Asfahani 《水文研究》2007,21(21):2934-2943
Twenty‐nine Schlumberger electrical soundings were carried out in the Salamiyeh region in Syria using a maximum current electrode separation of 1 km. Three soundings were made at existing boreholes for comparison. Aquifer parameters of hydraulic conductivity and transmissivity were obtained by analysing pumping test data from the existing boreholes. An empirical relationship between hydraulic conductivity determined from the pumping test and both resistivity and thickness of the Neogene aquifer has been established for these boreholes in order to calculate the geophysical hydraulic conductivity. A close agreement has been obtained between the computed hydraulic conductivity and that determined from the pumping test. The relationship established has, therefore, been generalized in the study area in order to evaluate hydraulic conductivity and transmissivity at all the points where geoelectrical measurements have been carried out. This generalization allows one to derive maps of the hydraulic conductivity and transmissivity in the study area based on geoelectrical measurements. These maps are important in future modelling processes oriented towards better exploitation of the aquifers. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
4.
A new and simple method based on a nonlinearly mathematical optimization concept has been proposed in this research to interpret magnetic anomalies due to vertical faults and thin dikes. This proposed interpretative method consists of three main steps. The first step is to formulate nonlinearly constrained optimization problems to describe the geophysical problems related to the studied structures. The second step is to suggest an interior penalty function in order to convert these nonlinearly constrained optimization problems into nonlinearly unconstrained optimization ones. The third step is to solve the converted nonlinearly unconstrained optimization problems by using the famous Hooke and Jeevess algorithm in order to estimate the geophysical parameters of the studied structures such as: depth, amplitude coefficient, and index parameter. The Hooke and Jeevess algorithm is purposely chosen for being robust and also its application to magnetic data converges rapidly towards the optimal estimation of parameters. This method was first tested on theoretical models with different random noise, where a very close agreement was obtained between the assumed and evaluated parameters. The validity of this new method was also tested on practical field examples taken from Australia, India, United States, and Brazil, where available magnetic data existed and was previously analyzed by different interpretative methods. The agreement between the results obtained by our developed method and those obtained by the other geophysical methods is good. The advantages of this newly proposed method, compared with the other published interpretative methods, also have been discussed and demonstrated. 相似文献
5.
Jamal Asfahani 《Acta Geophysica》2017,65(4):765-775
An alternative approach using nuclear neutron-porosity and electrical resistivity well logging of long (64 inch) and short (16 inch) normal techniques is proposed to estimate the porosity and the hydraulic conductivity (K) of the basaltic aquifers in Southern Syria. This method is applied on the available logs of Kodana well in Southern Syria. It has been found that the obtained K value by applying this technique seems to be reasonable and comparable with the hydraulic conductivity value of 3.09 m/day obtained by the pumping test carried out at Kodana well. The proposed alternative well logging methodology seems as promising and could be practiced in the basaltic environments for the estimation of hydraulic conductivity parameter. However, more detailed researches are still required to make this proposed technique very performed in basaltic environments. 相似文献
6.
Arétouyap Z. Bisso D. Njandjock Nouck P. Amougou Menkpa L. E. Asfahani J. 《Natural Resources Research》2019,28(1):63-77
This study was carried out in the Adamawa region, which connects Cameroon, Central African Republic, and Nigeria together. The main objective of this work is to assess the geophysical aspects of the local Pan-African hydraulic conductivity (K), using the vertical electrical sounding technique (VES) as an alternative approach to pumping test. This economical, less-time consuming, and easy-to-process alternative technique provides more accurate hydraulic conductivity values than the traditional pumping test technique. The K values obtained by the VES technique (ranging between 0.4 and 6.0 m/day) match those obtained by the pumping tests results. A thorough analysis of the transmissivity values reveals the existence of two aquifer trends in the region: Trend-1 with transmissivity values ranging from 34.22 to 39.27 m2/day with an average value of 35.44, and Trend-2, with transmissivity values of 7.87–34.44 m2/day with an average value of 16.56. Maps of transmissivity (T), resistivity (ρ), thickness (h), transverse resistance (TR), and hydraulic conductivity (K) of the Pan-African aquifer, derived from quantitative VES data interpretation, are established. These parameters are of paramount importance to the management of groundwater resources. They are important in the sense that geological contexts similar to that of Pan-African aquifer cut across Africa and South America. Therefore, this article will be valuable to regions worldwide that are geologically similar to the Adamawa Region.
相似文献7.
8.
Jamal Asfahani 《水文研究》2007,21(8):1085-1097
A resistivity survey is conducted in Khanasser Valley, a semi‐arid region in northern Syria, to delineate the characteristics of ground water affected by the salt‐water intrusion related to Al‐Jaboul Sabkha. Existing wells were used to measure salinity and conductivity of water samplings. Vertical electrical sounding was carried out near the existing wells. The combination of resistivity and hydrogeological data enables the establishment of empirical relationships between earth resistivity, water resistivity, and the amount of total dissolved solids. These relationships are then used in order to derive salinity maps for electrode spacings of 70, 100, and 150 m. The distribution of fresh, brackish and salt‐water zones and their variations in space along two longitudinal profiles (LP1 and LP2) are established through converting subsurface depth–resistivity models into different ground‐water areas. The constructed ground‐water area maps allow interfaces between different water zones to be determined. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
9.
A geophysical interpretative method is proposed to depth, amplitude coefficient and geometrical shape factor determination
of a buried structure from an observed gravity anomaly related to a cylinder or a sphere-like structure.The method is based
on nonlinearly constrained mathematical modelling and also on stochastic optimization approaches. The proposed interpretative
method first has been tested on theoretical synthetic models with different random errors at a certain depth, where a very
close agreement has been observed between assumed and evaluated parameters. Subsequent field data have been considered for
which the interpreted results by other methods are available for comparison. The agreement between the obtained results by
the proposed technique and by other geophysical methods is good. A statistical analysis has been also carried out to demonstrate
the accuracy and the precision of the suggested interpretative method. 相似文献
10.
The latent impact of the Ghab pull-apart basin tectonic setting and associated deformations resulting from active tectonics on the Qastoon Dam in northern Ghab in Syria have been evaluated. This was achieved by applying an appropriate methodology essentially based on morphotectonic mapping and integrated geophysical surveys consisting of electrical resistivity profiling, vertical electrical sounding and self-potential. The integrated interpretation of the acquired morphotectonic and geophysical data allowed the detection of subsurface deformed structures, either underlying the Qastoon Dam lake floor, or close to it. It is believed that these active structures were developed through the ongoing active tectonic processes occurring in the Northern Arabian plate. The tectonic survey proved that the N66.5°E striking Wadi Al Mashta fault, extending beneath the Qastoon Dam lake floor, is one of the youngest active structures, and that the intersection of the fault with the Qastoon Dam prism is a water-leaking point. Dam supporting measures, continuous monitoring and precautious disaster management are therefore recommended to be urgently adopted and practiced. 相似文献