الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The RTP reduced to the pole magnetic, the Bouguer gravity anomaly maps and the seismicity of the study area are used to reveal the deep–seated structural elements to evaluate the relation between the locations of these structures and the recent and the historical earthquakes, and to evaluate the seismic hazard affecting this area. The close inspection of the Bouguer anomaly map reveals the presence of four zones having different gravity anomaly patterns and shapes. The first zone comprises a narrow belt with three low gravity closures, from south to north, having -20, -25, -26 mGals in amplitude, respectively. They extend with their major areas parallel to the general trend of the Nile Valley reflecting the effect of the low density contrast between the Nile sediments and the underlying Eocene limestone bed rocks. The second oval shaped gravity low reaching up to -28 mGal in the area west of the of the Nile Valley between Qarun Lake and Abu Roash . It represents a major sedimentary basin containing a big thickness of sediments. The third zone comprises with a maximum gravity high that extends mainly ENE-WSW with local irregularities with a maximum gravity of +5 mGal, this belt represents major basement uplift with probable irregular surface, which extends further to the east and west of the study area. Finally a number of a relatively gravity high closures of small sizes occur east and west of the Nile Valley and represent local structural highs that delimit the borders of the Nile Valley. The RTP Magnetic map reveals the existence of a major ENEWSW low magnetic anomaly of about -220 gammas running diagonally parallel to Qarun Lake and extending nearly from the northeast to the southwest corner. At the northeastern part, the low magnetic anomaly has mostly E-W trend, then it changes its orientation to be ENE-WSW at the central part passing by Qarun Lake and continues to the southwest. The low magnetic trend is bounded by magnetic highs at the northwestern and southern parts. At the northwestern corner, a single circular high magnetic anomaly of about 300 gammas exists with a steep gradient to the east and gentle gradient to the west. At the southern half, there are many magnetic anomalies with variable amplitudes and directions ranging from high magnetic anomalies at the east to low magnetic at the west. These magnetic anomalies are mainly due to the relief of the basement rocks and basement related structures as well as variations in their susceptibility. Least - Square Method was carried out on the gravity data of the study area, the results are five residual maps. The correlation coefficients between the successive residual maps were computed in order to determine the optimum order of the regional surface to be used, It was found that, the least-squares gravity map of first order residual is closely similar to the Bouguer map represents the least-square gravity map with residual first order of the study area. This map characterizes by the presence of great negative anomalies occupies nearly the central part of the eastern side of this area. The regional gravity map after upward continuation were carried out to 2 km enhances the regional NE-SW gravity anomalies, shows gentle gravity gradient and increasing lateral extensions of these anomalies, Moreover the map shows attenuation and reduction of the number of the local gravity anomalies especially those trending N-S at the eastern side and the residual tends .The residual gravity map at 2 km shows the number of the local gravity anomalies and their gradient increases at the height of continuation increases. At the eastern and southern central parts, the N-S trending local anomalies became clearer. The N-S local gravity anomalies are related to shallow normal faults controlling the pass of the River Nile and the low density of the Nile sediments rocks. At the rest of the map, ENE-WSW, NE-SW and E-W trending local anomalies have been enhanced.