Ahmed Khalil

The goal of present study is determining subsurface structural elements by analyzing geomagnetic data sets aiming to examine their impacts on geological surface structures characterizing the western region in Beni-Suef Governorate, Western Desert, Egypt. A land-magnetic survey is conducted by two exceedingly sensitive proton magnetometers to measure the total intensity of geomagnetic field at the region under investigation. The measurements of regional gradients and time variation were applied to get the required reduction of daily variation. The regional expansions of subsurface structural units were obtained after applying the reduction to north magnetic pole (RTP) method to the corrected magnetic data acquired from land-magnetic survey along with Bouguer maps (1:100,000 scale and 1-mGal contouring interval). Regional-residual technique was applied depending on the power spectrum analysis. Moreover, the edge detection approach is conducted to depict the structures and subsurface h...

Symbiotic plant-fungi interaction is a promising approach to alleviate salt stress in plants. Moreover, endophytic fungi are well known to promote the growth of various crop plants. Herein, seven fungal endophytes were screened for salt tolerance; the results revealed that Aspergillus ochraceus showed a great potentiality in terms of salt tolerance, up to 200 g L−1. The indole acetic acid (IAA) production antioxidant capacity and antifungal activity of A. ochraceus were evaluated, in vitro, under two levels of seawater stress, 15 and 30% (v/v; seawater/distilled water). The results illustrated that A. ochraceus could produce about 146 and 176 µg mL−1 IAA in 15 and 30% seawater, respectively. The yield of IAA by A. ochraceus at 30% seawater was significantly higher at all tryptophan concentrations, as compared with that at 15% seawater. Moreover, the antioxidant activity of ethyl acetate extract of A. ochraceus (1000 µg mL−1) at 15 and 30% seawater was 95.83 ± 1.25 and 98.33 ± 0.57%,...

Arbuscular mycorrhizal fungi (AMF) and elevated CO2 (eCO2) have been effectively integrated to the agricultural procedures as an ecofriendly approach to support the production and quality of plants. However, less attention has been given to the synchronous application of AMF and eCO2 and how that could affect the global plant metabolism. This study was conducted to investigate the effects of AMF and eCO2, individually or in combination, on growth, photosynthesis, metabolism and the functional food value of Thymus vulgare. Results revealed that both AMF and eCO2 treatments improved the photosynthesis and biomass production, however much more positive impact was obtained by their synchronous application. Moreover, the levels of the majority of the detected sugars, organic acids, amino acids, unsaturated fatty acids, volatile compounds, phenolic acids and flavonoids were further improved as a result of the synergistic action of AMF and eCO2, as compared to the individual treatments. Ov...

In the present work, we present a reconnaissance study to elucidate and delin-eate the subsurface structures and tectonics of the area between Dahshour and El Fayoum province using available magnetic data; including land magnetic survey and aeromagnetic data. The study area has been selected due to its active tectonic situation. The magnetic data have been analyzed to provide new information about the tectonic setting and sub-surface structures of the study area. A detailed land magnetic survey has been carried out for the total component of geomagnetic field using two Proton magnetometers, one of them as a local reading base station placed in the middle part of the area, while the second was used for measuring the total intensity of the different points in a mesh-like configuration. The necessary corrections for the measured magnetic data have been car-ried out. The total land intensity and aeromagnetic maps have been reduced to the north magnetic pole. Moreover, wave number filter...

ABSTRACT The Fayoum–Cairo district lies in the south western part of Cairo, which is affected by several earthquakes. According to the Egyptian Network Seismology of National Research Institute of Astronomy and Geophysics (NRIAG), the last one occurred in the 31 st July, 2005 (Magnitude = 4.2 in Richter scale). Magnetotelluric (MT) method can offer good opportunity to detect crustal fluids along faults due to their high electrical conductivity anomalies. The targets of these measurements are various. Its always desired to determine the location(s) of active fault(s) to study the connection of the Fayoum–Cairo seismicity and MT resistivity structure. A single MT profile was carried out across the area in order to investigate the deep resistivity structures. Beside RTP aeromagnetic anomaly map was used to delineate the shallow structures. The area under study is located in the northern part of Egypt between latitudes 29° 40 ' N & 29° 55' N and longitudes 30° 55' E & 31° 20' E, occupying a total surface area of about 1225 km 2 (Fig. 1). The earthquake activity in Egypt is moderate (M≤6); but some events caused extremely severe damage to recent and historical constructions (Fig. 2b). The MT survey was conducted along eight stations on a northeast-southwest trending profile, selected perpendicular to the regional geologic structures and extremely for about 20 km of the study area (Fig. 2a). The Magnetotelluric method (MT) is an electromagnetic (EM) technique that is used to determine the electrical resistivity structure of the earth by measuring natural magnetic and electric fields at the surface. Two dimensional (2-D) inversions were applied to (MT) data. The reduced to the pole (RTP) aeromagnetic map compiled by the Western Digital Company (1983) has been used for determination of subsurface structures. Filtering, power spectrum and 2D-magnetic modeling were applied to the RTP aeromagnetic data.

An aeromagnetic reconnaissance study is presented to delineate the subsurface structure and tectonic setting at the Fayoum-Cairo district, which experienced a damaging earthquake on October 12, 1992 of magnitude (M = 5.7). Analysis of aeromagnetic and seismicity data demonstrate three significant tectonic faults with trending to the NE-SW, NW-SE and E-W. The basement is uplifted in the northern and central parts with a depth of 1.3 km, and deepening in the southern part with a depth of 2.5 km. This is a seismically active zone and historically has experienced damaging earthquakes. In 1847, a damaging earthquake with maximum epicentral intensity (Modified Mercalli Intensity (MMI) = VII) was located there. On the eastern side, earthquake sources are well recognized at different locations. These sources created events of moderate size magnitude M < 5. The focal mechanisms of the major events from these sources are generally strike-slip with normal component. The focal mechanism of t...

ABSTRACT Esh El Mellaha area is located on the western coast of the Gulf of Suez, which is considered the main hydrocarbon resource in Egypt. The main exploration problems in and around the Gulf of Suez due to the complexity of the basement structure and the Pre-Miocene salt formation that masks the seismic energy. This study is to image the subsurface structure of the study area using the available magnetic data based on the Euler method. The Euler method is applied to the TMI anomaly map as well as regional and residual components of the TMI data. The results indicate that the area is dissected by a system of faults with NW and NE strike. Generally, Application of the Euler method to separated components of the crustal magnetic field provided results superior to those obtained from total-field anomalies.

ABSTRACT Several earthquakes occurred at the Cairo- Faiyum road, south western part of Cairo. Seismology data provides information about the locations and depths of the earthquakes, however, the extension of the tectonic, based on the earthquake data, is approximated. The interpretation of the magnetic data has highly contribution to prove or deny the approximated tectonic trends. In this study, magnetic and seismological data (which is said to have been in existence since 2200 B.C.) is integrated to trace the tectonic trends on which the earthquakes were occurred. New potential field interpretation methods are used to process and analyze the data. The result of this work indicates that there are major faults beneath and cross the Nile River trending in EW, more or less parallel to the main active fault zones. Additionally, a large circular magnetic source is located beneath the Nile River-Cairo area, at depth of 10 km. From the previous results, the Cairo area is said to be an active zone and recommendation is given to decision makers for the high hazards that Cairo suffers.

One of the most famous problem faces the coastal agricultural area is the saline-water intrusion from sea. This study endeavors at detailing the prevailing subsurface conditions from the viewpoint of groundwater location, depth and quality. Two well-known geophysical methods have been used and applied to determine the depth of the fresh water aquifer and the saline water intrusion. The vertical electrical sounding and time-domain electromagnetic sounding have been pertained in the same 67 sites, which covers the study area. Analysis and interpretation of the obtained results reveals that, the subsurface consists of three geo-electrical layers with a gentle general slope towards the sea. The fresh water overlies saline water. It deserves mention to note that the fresh water depth varies between 0.5 and 65 m. under the ground surface. The saline water depth varies between 23 and 83 m. below the ground surface.

Abstract: In the present work, we present a reconnaissance study to elucidate and delineate the subsurface structures and tectonics of the area between Dahshour and El Fayoum province using available magnetic data; including land magnetic survey and ...

ABSTRACT EL Fayoum–Cairo district lies in the north western part of Cairo city. It is affected by several earthquakes. According to the Egyptian Network Seismology of National Research Institute of Astronomy and Geophysics (NRIAG), the last one occurred in July 2005 with a magnitude of 4.2 in Richter scale. The Bouguer and the aeromagnetic anomaly data as well as the detailed land-magnetic survey have been subjected to different techniques of processing and interpretation to better understand the tectonic setting of the study area. For example, different kinds of filters such as 2D spectral analysis, 3D analytical signal, and Euler deconvolution techniques have been applied. Finally, the 2D modeling has been used to simulate the subsurface configuration along some selected profiles at the area. It can be noticed from the obtained results that, the seismic events (Dahshour earthquakes) are closely related to a major NNW normal fault which has a deep extension and slightly lateral displacement, in addition to its NE-conjugate faults. The recent seismic activities in the study area are directly related and/or associated with the rejuvenation of the lateral movements. Three-dimensional interpretations of the magnetic anomaly and Bouguer anomaly maps of Fayoum, Cairo province area, Northern Western Desert of Egypt have been presented. In addition, a high-resolution 3D magnetic and gravity model constrained with the seismic results reveals a possible crustal thickness and density distribution of the northern part of Egypt between the sedimentary cover and the mantel. The results reveal that the basement has an irregular surface with depths ranging from 3,600 to 5,500 m. Faults of the NNW, as well as ENE and NE directions have predominated and affected both the basement and the overlying sedimentary cover. Furthermore, the 2D modeling technique across long gravity and magnetic anomaly profiles have emphasized the basement topography and its overlying sedimentary section. The agreement between the results of gravity and magnetic surveys and geology on the other hand, confirm the reliability of the chosen constraints of interpretation.

When the solar irradiance propagates between the outer magnetospheric regions and the ionosphere, dynamic processes of the magnetosphere-ionosphere-thermosphere system are affected at the lower end of their paths by the interaction of radiation with the neutral troposphere. The main target of this work is to investigate the relationship between the diurnal magnetic field variations resulting from solar activities and the variation in the troposphere temperature. Meteorological and geomagnetic data acquired from different observatories located in Egypt, Portugal and Slovakia in a long-term and daily-term scales were analyzed.The long-term results show that there is a close relationship between the diurnal Sq magnetic field variations and the tropospheric temperature. The rate of temperature increase at mid-latitude areas is higher than at high-latitude. During the period of investigation, it is found that the troposphere temperature has increased by about 0.033 °C/year at Helwan, Egy...

ABSTRACT Minami-Noshiro oil field is considered as one of the most important oil fields in Japan. A threedimensional magnetotelluric (MT) survey was conducted in this area by Japan National Oil Corporation (JNOC). In this study the magnetotelluric data have been used to image the electrical conductivity of the subsurface in the study area. The used frequency of the MT data was ranging from 0.00055 to 320 Hz. The study of the dimensionality and directionality of the regional electrical structures