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Abu-Dabbab area is the most active seismic zone in the central Eastern Desert of Egypt, where seismic activities are daily recorded. The reported earthquakes are microearthquakes of local magnitudes (ML < 2.0). A spatial distribution of these microearthquakes shows that the earthquakes of the area follow an ENE-WSW trending pattern, which is nearly perpendicular to the Red Sea Rift. Focal mechanisms of different fault styles were recognized with dominant normal faulting (with a strike-slip component) events characterized by focal depths greater than 7 km and reverse ones of shallower focal depths. Several lines of evidence indicating that the brittle-ductile transition zone underlies the Abu-Dabbab area occurs at a relatively shallow depth (10-12 km) and it is acting as a low-angle normal shear zone (LANF). Field-structural, EMR and seismic data (this study) reveal that the maximum compressive stress (σ1) in the area is perturbed from the regional NW-SE direction to ENE-WSW orientation. This stress rotation is evidently akin to the reactivation of the crustal scale Najd Fault System (NFS), where such reactivation is attributed to the ongoing activity/opening of the Red Sea. Our tectonic model proposes that the continuous activity on the brittle-ductile transition zone including the LANF led to stress localization, which triggering a brittle deformation in the upper crustal-levels and associated shallow dipping thrusts. Such bimodal tectonic model suggests that the deep earthquakes are owing to the tectonic movement on the LANF (transtension), whereas the shallow earthquakes are related to a brittle deformation inside the fault blocks of the upper crust (transpression). Deformation creep along this zone didn't permit continuous accumulation of strain and hence reduce the possible occurrence of large earthquakes. [ABSTRACT FROM AUTHOR]

An active fault system has been detected along the Cairo-Suez district in northeastern Egypt, applying the EMR-Technique using Cerescope. The E-W (old Mediterranean) and NW-SE (Red Sea-Gulf of Suez) fault-trends are estimated to have ongoing activity. Horizontal EMR-measurements indicate a NW to NNW orientation as a maximum horizontal stress direction (σ 1 ), whereas an E-W orientation to has a secondary tendency. A simplified stress map for the Cairo-Suez district is constructed from the horizontal stress data measured at about 20 locations within the district. The mapped stresses will contribute to the stress data of the Cairo-Suez region on the world stress map (WSM). The present study results indicate rejuvenation of the inherited Mesozoic E-W oriented and Oligocene-Miocene rift-related NW-SE oriented faults. The transfer of rift-related deformation from Red Sea-Gulf of Suez region, which is currently undergoing an extensional stress regime in NE to NNE direction, would explain a seismotectonic activity of the Cairo-Suez district. These results are consistent with a present day NNW oriented compressional stresses attributed to a convergence between the African and Eurasian plates. [ABSTRACT FROM AUTHOR]

Two conjugate sets of active faults oriented NNE–SSW and NNW–SSE have been detected at Landau area in SW Germany. These faults follow the old trends of the rift-related structures predominating in the Upper Rhine Graben (URG), which originated during Late Eocene–Miocene time. Linear and horizontal measurements were performed by using the Cerescope device and interpreted, applying the Electromagnetic Radiation (EMR) Technique. Linear EMR-profiles were helpful for mapping active faults, while the main horizontal stress (σ H , N to NNE) was easily identified with EMR-horizontal measurements. Reactivation of rift-related structures of the Upper Rhine Graben at Landau area produces a new system of active shallow fractures following old trends, and has been detected through the present study by Cerescope applying the EMR-Technique. The present results imply that the Enhanced Geothermal System (EGS) to the south of Landau has a great impact on reactivation of the pre-existing rift-related faults by mechanical hydro-fracturing occurring within the reservoir rocks underneath the area. [ABSTRACT FROM AUTHOR]

The seismotectonic activity in Northeastern Egypt is intimately related to the active tectonic structures (mainly faults) which deform the region and induce intraplate seismicity. The present contribution is a new attempt to integrate structural, remote sensing, and seismic data, and implement a reliable geospatial analysis to investigate and assess the nature of the relation between tectonic structures and seismotectonic activity in the Cairo–Suez district which is an active seismic source zone in Northeastern Egypt. The achieved remote sensing and GIS-based geospatial analysis introduces valuable information on the frequency, orientation, and density of investigated tectonic fault trends. The spatial distribution of earthquakes epicenters which recorded during the period (1997–2016) with magnitude (ML ≥ 3.0) is evidently interrelated with the detected tectonic trends, and normal faulting with subordinate shear component is the most focal mechanisms indicated from the analyzed seismic events. The depth analysis of the studied earthquakes suggests a "hard linkage" between the major rift-boundary faults in the northern Gulf of Suez rift and the tectonic trends in the southern domain of the Cairo–Suez district, and thus indicates seismic activity on relatively deeper crustal levels. Most of the studied earthquakes have occurred on the WNW–ESE to NW–SE oriented faults in predominantly extensional to transtensional stress regime, which indicating the WNW to NW tectonic trend as an active fault trend. The intraplate seismotectonic activity in Northeastern Egypt is highly controlled by two active tectonic boundaries, the Red Sea–Gulf of Suez rift and Aqaba–Dead Sea transform (to the east) and the Pelusium Shear System (PSS, to the west). Any reliable hypothetical model explaining the seismotectonic setting in such region would consider the Cairo–Suez district as a large transfer zone transmitting the "far-field" stresses northwestward to the PSS with an effective mechanism keeping the within-plate WNW–ESE, NW–SE, and E–W tectonic trends highly prone to rejuvenation and seismic rupture. [ABSTRACT FROM AUTHOR]

Detailed subsurface mapping and structural analysis of El-Gindi basin indicate the hydrocarbon potentiality of the Cretaceous reservoirs. El-Gindi basin is a Late Cretaceous-Eocene basin located at El-Fayium district, northeastern Western Desert of Egypt. The overwhelming impact of the Late Cretaceous wrench tectonics was evident during the inversion of the Jurassic-Early Cretaceous rift-related basins along the North Western Desert of Egypt and subsequent deposition of a thick succession of Eocene sediments (~6000 ft Apollonia Formation) within El-Gindi Basin. These tectonic events were developing the oil maturity and trapping through the Late Cretaceous reservoir sequences, Upper Bahariya Formation (Cenomanian) and the Abu Roash "G" Member (Turonian). The Gindi Fault, however, is a NW-trending basement feature breaching El-Gindi basin and bounding several deeper half grabens in the western half of El-Fayium district. It has been reactivated during the Cretaceous, Eocene and probably Oligocene-Early Miocene times, where extended northwestward to the Qarun Field at the footslopes of the Kattaniya inverted basin forming several oil traps along its strike. The Late Cretaceous dextral wrenching developed a regional system of ENE-oriented structural ridges such as Kattaniya and Silah (bounded El-Gindi basin to the north and south, respectively), associated with a series of NE-to ENE- oriented right-lateral strike-slip faults enclosing some structural closures in between. The development of such ridges causing regional subsidence and subsequent deposition of the Apollonia Formation creating several structural hydrocarbon traps. In addition, the structural closures formed between the ends of right-lateral strike-slip faults at Silah High became potential sites for hydrocarbon accumulation. The thermal maturity model of El-Gindi basin suggests a phase of hydrocarbon expulsion occurred during or immediately after deposition of the Apollonia Formation, where the Lower and Upper Cretaceous sediments passing the oil window. According to the analysis of well cores, E-logs and seismic data, shallow marine to deltaic environments have been assigned for the Cenomanian-Turonian reservoir sediments. Moreover, the deposition within channels, point-bars and estuarine environments for the hydrocarbon bearing sandstone reservoirs within El-Gindi Basin was identified. • El-Gindi basin is a Late Cretaceous-Eocene basin. • Late Cretaceous dextral-transpression developed several hydrocarbon traps. • The structural closures at Silah High became potential sites for hydrocarbon accumulation. • Hydrocarbon expulsion occurred during or immediately after deposition of the Apollonia Formation. • Shallow marine to deltaic environments are assigned for Cenomanian-Turonian reservoirs. [ABSTRACT FROM AUTHOR]