Saad Mogren | King Saud University (original) (raw)
Papers by Saad Mogren
Journal of Applied Geodesy, Aug 14, 2023
A high-resolution gravimetric geoid model was developed for the Eastern Province Kingdom of Saudi... more A high-resolution gravimetric geoid model was developed for the Eastern Province Kingdom of Saudi Arabia region. The model was created using various datasets, including 320,434 land gravity measurements, 5442 shipborne marine gravity data, the DTU17 altimetry gravity model, and the XGM2019e global geopotential model. The computation strategy employed for modeling the gravimetric geoid involved the Remove-Compute-Restore method with Residual Terrain Model reduction and the 1D-Fast Fourier Transform approach technique. Geoid heights were determined using the Stokes integral with the Wong-Gore modification. To assess the accuracy of the resulting geoid models, they were compared with 4401 GNSS/Levelling points. The geoid accuracy throughout the entire area is better than 1.6 cm in terms of standard deviation (STD) after fitting.
The Egyptian Journal of Remote Sensing and Space Science, Aug 1, 2023
Journal of Petroleum Science and Engineering, 2020
The current study aimed to explore the gas-generating potential and oil-togas conversion in the M... more The current study aimed to explore the gas-generating potential and oil-togas conversion in the Madbi oil-source rock system based on data from deep well within the Say'un-Masila Basin using both geochemical and petrological methods as well as basin models. Biomarker results for the bitumen from analyzed shale samples indicate mixed organic matter, with mainly phytoplankton, bacteria, and some terrigenous land plants, deposited under relatively anoxic marine environmental conditions. The terrigenous organic matter, and rich in lipids from phytoplankton and bacteria, suggests Types II and II/III as the original organic matter during deposition. Such findings are not consistent with the significant amounts of vitrinite and inertinite that found under microscope and the low current hydrogen index (HI) values of 43-282 (Types III/IV and III/II kerogen) of the analyzed shale samples. The chemical and optical maturity indicators show that the Madbi shales throughout the studied well section are at different thermal maturity stages, consistent with late-mature stage of the oil window to gasgeneration window. Therefore, this high thermal maturation is the critical factor that significantly modifies the original organic matter. Based on the basin models of the single well studied (Ghayl Bin Yumain-01), the initial conversion of kerogen to oil, occurring between the Late Cretaceous and Late Eocene (75-38 Ma), corresponding to peak-oil window (0.70-1.00 Easy %R o). Furthermore, the oil was expelled during the Late Eocene to Early Oligocene; hence, the late-mature stage of the oil window (1.00-1.30 Easy %R o) commenced during this time, with transformation ratios (TR) of 50-70%. Subsequently, the cracking of the retained oil into gas has occurred from the Early Oligocene through the present and is attributed to the high thermal maturation of the gas window (>1.30 Easy % R o), with maximum TRs of 70-97%.
Advances in science, technology & innovation, 2019
This study presented the importance of the new absolute gravity measurements in bringing all grav... more This study presented the importance of the new absolute gravity measurements in bringing all gravity surveys of Saudi Arabia into one unified datum, absolute gravity was measured using FGL absolute gravity meter from 2008 to 2015, and the resultant data showed excellent coherences from 2008 to 2012 with small change of approximately 10 μGal. However, notable decrease of 31.77 μGal from 2012 to 2015 which was either due to water-level changes or the fact that the instrument was recently repaired and some parts were replaced. Nevertheless, the obtained accuracy was sufficient for geophysical and geoidal applications. A new correction value (13.117 mGal) for Potsdam datum was determined which can be used to adjust old gravity surveys tied to Potsdam datum to the new KSU gravity base station.
Arabian Journal of Geosciences, 2021
The active tectonics of the Gulf of Aqaba (Red Sea) may affect the newly established NEOM megacit... more The active tectonics of the Gulf of Aqaba (Red Sea) may affect the newly established NEOM megacity in northwestern Saudi Arabia. Using seismological and potential field data, this study aimed to evaluate the major tectonic trends around NEOM area and their hazard impacts on the NEOM area. In particular, aeromagnetic and gravity data were used to explore the major tectonic trends that may affect this area. The interpreted tectonic trends are directed mainly along the NNE and NNW, as well as NW and EW tectonic trends. A good correlation was found between the distribution of the earthquake epicenters ( M w ≥ 4) and the interpreted tectonic trends. Moreover, the distribution of epicenters was congruent with the fault trends obtained from the potential field data, implying that the observed fault trends can generate earthquakes. For the seismic hazard assessment, the source parameters and expected ground motions of two moderate earthquakes that occurred in the Gulf of Aqaba in 2015 and 2016 were analyzed. Assuming an omega-squared source model, a grid search method was applied to fit the amplitude spectra of the S -wave group over the model parameters that were used to compute M o values of 4.06E + 23 and 2.14E + 23 Nm, corresponding to M w of 5.0 and 4.8, fault radii of 831 m and 835 m, and stress drop (Δσ) values of 7.72 and 4.01 MPa for the 2015 and 2016 earthquakes, respectively. An empirical Green’s function summation technique was performed to simulate high-frequency ground motions expected for future large earthquakes, demonstrating the influence of such earthquakes on the study area. For a Δσ value of 10 Mpa (characteristic of past earthquakes in the Gulf of Aqaba), peak ground accelerations of ∼ 5.6 and 5.53 m/s 2 are to be expected for future earthquakes with Mw 7.0 in the epicentral regions of the 2015 and 2016 earthquakes.
Journal of African Earth Sciences
Arabian Journal for Science and Engineering, 2012
As the most valuable natural resources, protection and management of groundwater is vital for hum... more As the most valuable natural resources, protection and management of groundwater is vital for human evolution, socioeconomic development and ecological diversity. This paper presents the groundwater vulnerability mapping of the Quaternary aquifer system in the northeastern part of Nile Delta using Weighted Multi-Criteria Decision Support System model (WMCDSS). This model has been implemented using Geographic Information System to delineate groundwater zones and to suggest a protection and improvement plan for major groundwater wells in the area. Six thematic layers were digitally integrated after assigning different weights (W f) and rates (R f) to them. These GIS layers have been created to adopt the most indicative criteria for investigating the groundwater degradation trends from sea level rise and seawater intrusion. The chosen layers are: total dissolved solids (TDS), rCl/rHCO 3 ratio, sodium adsorption ratio (SAR), groundwater type, hydraulic conductivity (K) and well discharge (Q). Weights have been assigned to all these layers according to their relative importance for groundwater vulnerability, whereas their corresponding normalized weights were obtained from their effectiveness factors. The groundwater vulnerability map indicates four classes ranging from very low to high. According to this map, the promising localities for groundwater usage are located in areas where very low to low vulnerability has been observed. These localities are distributed over 4080 Km 2 area, covering 53.68% of the total study area. The areas having moderate to high groundwater vulnerability are more than 3520 Km 2 , indicating a deterioration of groundwater quality in 46.32% of the study area, which need special treatment and cropping pattern before use.
Journal of King Saud University - Science
![Research paper thumbnail of Corrigendum to “Mapping b-value for 2009 Harrat Lunayyir earthquake swarm, western Saudi Arabia and Coulomb stress for its mainshock” [J. Volcanol. Geotherm. Res. 330 (15 January 2017) 1–23]](https://attachments.academia-assets.com/96839611/thumbnails/1.jpg)
](Journal of Volcanology and Geothermal Research, 2019
Wajid Formation is one of the most important waterbearing aquifers in the central part of Saudi A... more Wajid Formation is one of the most important waterbearing aquifers in the central part of Saudi Arabia. It consists from sandstone lithology of Lower Carboniferous age. Due to lack of drilling, the petrophysical characteristic of this aquifer is not clearly understood. The aim of this work is to study the petrophysical properties of Wajid Formation using the available well logging datasets. The analysis revealed the presence of three different zones. A middle zone consists mainly of shale with bad properties (low permeability < 0.002 mD; high shale > 95%; and very low effective porosity < 1%). Two overlying and underlying zones of good petrophysical characteristics (low shale < 10%; good effective porosity > 10% up to 16%) and fair to good permeability for the upper zone, 0.2 2.0 mD) and very good permeability (5.0 mD) for lower zone. Petrophysically, the lower zone is the best and we do recommend using it in water production and other purposes.
Journal of the Indian Society of Remote Sensing, 2015
ABSTRACT Geological and structural mappings of Tayyib Al-Ism area were carried out using the rock... more ABSTRACT Geological and structural mappings of Tayyib Al-Ism area were carried out using the rocks finite strain data, the Landsat-7 Enhanced Thematic Mapper Plus (ETM+) data and the field based observations. To analyze the finite strain in the studied rocks, the Rf /ϕ and Fry methods are applied to feldspar porphyroclasts and mafic grains from nine metavolcano-sedimentary samples (Hegaf Formation), four diorite-gabbros suite samples (Sawawin Complex), two meta-granite samples (Ifal suite) and five Zuhd alkali granite samples. The obtained data indicate traces of high to moderate level of deformation in the meta-granite and metavolcano-sedimentary rocks. The axial ratios along the XZ section range from 1.70 to 4.80 for the Rf/ϕ method and from 1.50 to 4.50 for the Fry method. A sub-vertical trend of short axes in association with sub-horizontal foliation is also observed. These informations allow us to conclude that a finite strain in the deformed granitic rocks is of the same order of magnitude as in the metavolcano-sedimentary rocks. The contacts between the metavolcano-sedimentary and granitic rocks in Tayyib al Ism area were formed during the granitic intrusions along some of the faults under brittle to semi-ductile deformation conditions. These faults have significantly influenced the geometry and style of rifting in the Red Sea during the Neogene. The finite strain was accumulated in the area during the process of deformation, which superimpose the already existed nappe structure. It indicates that the nappe contacts formed during the accumulation of finite strain. In addition to finite strain analysis, band ratio images (3/1, 5/3, 7/5) and Principal Component Analysis (PCA) technique have been used, which proved effective in mapping geological and structural features of various rock bodies exposed in the study area
Tectonophysics, 2013
The Atlas orogeny in northern Algeria and Tunisia led to the destruction of Tethys oceanic lithos... more The Atlas orogeny in northern Algeria and Tunisia led to the destruction of Tethys oceanic lithosphere and cumulated in a collision of microplates rifted off the European margin with the North African continental margin. The location of the boundary between African plate and Kabylian microplate is expressed in northern Algeria by a crustal wedge with double vergence of thrust sheets, whereas in northern Tunisia the geologic environment is more complex and the location of the plate boundary is ambiguous. In this study, we analyzed gravity data to constrain the crustal structure along the northern margin of Tunisia. The analysis includes a separation of regional and residual gravity anomalies and the application of gradient operators to locate density contrast boundaries. The horizontal gradient magnitude and directional gradient highlight a prominent regional E-W gravity gradient in the northern Tunisian Atlas interpreted as a deep fault (active since at least the Early Mesozoic) having a variable kinematic activity depending on the tectonic regime in the region. The main E-W gravity gradient separates two blocks having different gravitational and seismic responses. The southern block has numerous gravity lineaments trending in different directions implying several density variations within the crust, whereas the northern block shows a long-wavelength negative gravity anomaly with a few lineaments. Taking into account the geologic context of the Western Mediterranean region, we consider the E-W prominent feature as the boundary between African plate and Kabylian microplate in northern Tunisia that rifted off Europe. This hypothesis fits most previous geological and geophysical studies and has an important impact on the petroleum and mineral resource prospection as these two blocks were separated by an ocean and they did not belong to the same margin.
Journal of Coastal Research, 2014
A research project on the Saudi Gulf of Aqaba was initiated in January 2012 to evaluate, protect,... more A research project on the Saudi Gulf of Aqaba was initiated in January 2012 to evaluate, protect, and develop a proper management plan for sustainable use of water resources in the coastal region. Within the framework of this project, a total of 85 surface water samples was collected and investigated to document the surface distribution of the hydrographical parameters (including water temperature, salinity, density, hydrogen ion concentration, and dissolved oxygen) as well as concentration of the nutrient salts (ammonium, nitrite, nitrate, phosphate, and silicate). The results show no thermocline or thermal pollution in the studied water and that they are mostly well oxygenated. In addition, no significant variations in the pH and salinity values have been observed. Relatively low levels of nitrogen, phosphorus (in the dissolved and total forms), and reactive silicate are observed. Inorganic nitrogen is found in the order of NO 3-N. NO 2-N. NH 4-N. On the basis of the relatively low level of nutrient salts, the Gulf of Aqaba coastal water is classified as oligotrophic to mesotrophic in nature, and the study area is not yet seriously affected by contamination in spite of rapid population growth and fast infrastructural/recreational development during the past decade.
GEOPHYSICS, 1989
Until 216 vertical electrical Schlumberger soundings were made, little was known about the subsur... more Until 216 vertical electrical Schlumberger soundings were made, little was known about the subsurface geology at the Wadi Surdud area in the coastal plain of the Yemen Arab Republic. These soundings provide information on the distribution of aquifers, aquitards, and impermeable rocks, and the salinity of the groundwater. A first, qualitative interpretation of the geoelectrical sounding curves gives a general impression of the hydrogeologic setting and the aquifer boundaries. However, a more detailed, quantitative interpretation shows that no single resistivity model completely satisfies all the hydrogeologic and geologic facts and theories. Basically, two different models are possible: in one the thickness of the aquifer is fixed; in the other, its resistivity is fixed. Several geologic and hydrogeologic hypotheses may be put forward to support each model, varying from relying upon tectonic events and sedimentary depositional environments to influences of agriculture and water abstr...
Geochemistry, Geophysics, Geosystems, 2009
A global Earth Magnetic Anomaly Grid (EMAG2) has been compiled from satellite, ship, and airborne... more A global Earth Magnetic Anomaly Grid (EMAG2) has been compiled from satellite, ship, and airborne magnetic measurements. EMAG2 is a significant update of our previous candidate grid for the World Digital Magnetic Anomaly Map. The resolution has been improved from 3 arc min to 2 arc min, and the altitude has been reduced from 5 km to 4 km above the geoid. Additional grid and track line data have been included, both over land and the oceans. Wherever available, the original shipborne and airborne data were used instead of ...
Arabian Journal of Geosciences
critical economic and social significance to the region, where groundwater is the sole source of ... more critical economic and social significance to the region, where groundwater is the sole source of irrigation and drinking water. Evaluation of groundwater quality of the coastal aquifers revealed that groundwater salinization is widespread. Groundwater samples exceeded the permissible limits for the majority of drinking water parameters tested except for dissolved metals. The occurrence of very low trace element levels probably reflects natural sources. The distributions of total dissolved solids were found to vary spatially. The variability observed within the groundwater samples is primarily related to seawater intrusion, mineral dissolution in the aquifer, distance from the sea, solutes in recharging water, time of year. Wells located in the upper north part of the study area were highly contaminated compared to southern wells. In addition, the occurrence of high salinity in the northern wells may be the result of surface water flow direction, where leaching and runoff flushing through the basin occur. Saline groundwater might occur due to both high evaporation and dissolution of evaporate minerals. Nitrate concentrations are variable but showed elevated levels. Evaluation of usability of groundwater aquifer for irrigation revealed that the majority of wells are generally not suitable for irrigation use under normal conditions but rather for salt-tolerant plants or livestock watering.
Acta Geophysica, 2016
This study integrates potential gravity and magnetic field data with remotely sensed images and g... more This study integrates potential gravity and magnetic field data with remotely sensed images and geological data in an effort to understand the subsurface major geological structures in Afghanistan. Integrated analysis of Landsat SRTM data was applied for extraction of geological lineaments. The potential field data were analyzed using gradient interpretation techniques, such as analytic signal (AS), tilt derivative (TDR), horizontal gradient of the tilt derivative (HG-TDR), Euler Deconvolution (ED) and power spectrum methods, and results were correlated with known geological structures. The analysis of remote sensing data and potential field data reveals the regional geological structural characteristics of Afghanistan. The power spectrum analysis of magnetic and gravity data suggests shallow basement rocks at around 1 to 1.5 km depth. The results of TDR of potential field data are in agreement with the location of the major regional fault structures and also the location of the basins and swells, except in the Helmand region (SW Afghanistan) where many high potential field anomalies are observed and attributed to batholiths and near-surface volcanic rocks intrusions. STRUCTURAL INVESTIGATIONS OF AFGHANISTAN 979 A high-resolution airborne geophysical survey in the data sparse region of eastern Afghanistan is recommended in order to have a complete image of the potential field anomalies.
Journal of Applied Geodesy, Aug 14, 2023
A high-resolution gravimetric geoid model was developed for the Eastern Province Kingdom of Saudi... more A high-resolution gravimetric geoid model was developed for the Eastern Province Kingdom of Saudi Arabia region. The model was created using various datasets, including 320,434 land gravity measurements, 5442 shipborne marine gravity data, the DTU17 altimetry gravity model, and the XGM2019e global geopotential model. The computation strategy employed for modeling the gravimetric geoid involved the Remove-Compute-Restore method with Residual Terrain Model reduction and the 1D-Fast Fourier Transform approach technique. Geoid heights were determined using the Stokes integral with the Wong-Gore modification. To assess the accuracy of the resulting geoid models, they were compared with 4401 GNSS/Levelling points. The geoid accuracy throughout the entire area is better than 1.6 cm in terms of standard deviation (STD) after fitting.
The Egyptian Journal of Remote Sensing and Space Science, Aug 1, 2023
Journal of Petroleum Science and Engineering, 2020
The current study aimed to explore the gas-generating potential and oil-togas conversion in the M... more The current study aimed to explore the gas-generating potential and oil-togas conversion in the Madbi oil-source rock system based on data from deep well within the Say'un-Masila Basin using both geochemical and petrological methods as well as basin models. Biomarker results for the bitumen from analyzed shale samples indicate mixed organic matter, with mainly phytoplankton, bacteria, and some terrigenous land plants, deposited under relatively anoxic marine environmental conditions. The terrigenous organic matter, and rich in lipids from phytoplankton and bacteria, suggests Types II and II/III as the original organic matter during deposition. Such findings are not consistent with the significant amounts of vitrinite and inertinite that found under microscope and the low current hydrogen index (HI) values of 43-282 (Types III/IV and III/II kerogen) of the analyzed shale samples. The chemical and optical maturity indicators show that the Madbi shales throughout the studied well section are at different thermal maturity stages, consistent with late-mature stage of the oil window to gasgeneration window. Therefore, this high thermal maturation is the critical factor that significantly modifies the original organic matter. Based on the basin models of the single well studied (Ghayl Bin Yumain-01), the initial conversion of kerogen to oil, occurring between the Late Cretaceous and Late Eocene (75-38 Ma), corresponding to peak-oil window (0.70-1.00 Easy %R o). Furthermore, the oil was expelled during the Late Eocene to Early Oligocene; hence, the late-mature stage of the oil window (1.00-1.30 Easy %R o) commenced during this time, with transformation ratios (TR) of 50-70%. Subsequently, the cracking of the retained oil into gas has occurred from the Early Oligocene through the present and is attributed to the high thermal maturation of the gas window (>1.30 Easy % R o), with maximum TRs of 70-97%.
Advances in science, technology & innovation, 2019
This study presented the importance of the new absolute gravity measurements in bringing all grav... more This study presented the importance of the new absolute gravity measurements in bringing all gravity surveys of Saudi Arabia into one unified datum, absolute gravity was measured using FGL absolute gravity meter from 2008 to 2015, and the resultant data showed excellent coherences from 2008 to 2012 with small change of approximately 10 μGal. However, notable decrease of 31.77 μGal from 2012 to 2015 which was either due to water-level changes or the fact that the instrument was recently repaired and some parts were replaced. Nevertheless, the obtained accuracy was sufficient for geophysical and geoidal applications. A new correction value (13.117 mGal) for Potsdam datum was determined which can be used to adjust old gravity surveys tied to Potsdam datum to the new KSU gravity base station.
Arabian Journal of Geosciences, 2021
The active tectonics of the Gulf of Aqaba (Red Sea) may affect the newly established NEOM megacit... more The active tectonics of the Gulf of Aqaba (Red Sea) may affect the newly established NEOM megacity in northwestern Saudi Arabia. Using seismological and potential field data, this study aimed to evaluate the major tectonic trends around NEOM area and their hazard impacts on the NEOM area. In particular, aeromagnetic and gravity data were used to explore the major tectonic trends that may affect this area. The interpreted tectonic trends are directed mainly along the NNE and NNW, as well as NW and EW tectonic trends. A good correlation was found between the distribution of the earthquake epicenters ( M w ≥ 4) and the interpreted tectonic trends. Moreover, the distribution of epicenters was congruent with the fault trends obtained from the potential field data, implying that the observed fault trends can generate earthquakes. For the seismic hazard assessment, the source parameters and expected ground motions of two moderate earthquakes that occurred in the Gulf of Aqaba in 2015 and 2016 were analyzed. Assuming an omega-squared source model, a grid search method was applied to fit the amplitude spectra of the S -wave group over the model parameters that were used to compute M o values of 4.06E + 23 and 2.14E + 23 Nm, corresponding to M w of 5.0 and 4.8, fault radii of 831 m and 835 m, and stress drop (Δσ) values of 7.72 and 4.01 MPa for the 2015 and 2016 earthquakes, respectively. An empirical Green’s function summation technique was performed to simulate high-frequency ground motions expected for future large earthquakes, demonstrating the influence of such earthquakes on the study area. For a Δσ value of 10 Mpa (characteristic of past earthquakes in the Gulf of Aqaba), peak ground accelerations of ∼ 5.6 and 5.53 m/s 2 are to be expected for future earthquakes with Mw 7.0 in the epicentral regions of the 2015 and 2016 earthquakes.
Journal of African Earth Sciences
Arabian Journal for Science and Engineering, 2012
As the most valuable natural resources, protection and management of groundwater is vital for hum... more As the most valuable natural resources, protection and management of groundwater is vital for human evolution, socioeconomic development and ecological diversity. This paper presents the groundwater vulnerability mapping of the Quaternary aquifer system in the northeastern part of Nile Delta using Weighted Multi-Criteria Decision Support System model (WMCDSS). This model has been implemented using Geographic Information System to delineate groundwater zones and to suggest a protection and improvement plan for major groundwater wells in the area. Six thematic layers were digitally integrated after assigning different weights (W f) and rates (R f) to them. These GIS layers have been created to adopt the most indicative criteria for investigating the groundwater degradation trends from sea level rise and seawater intrusion. The chosen layers are: total dissolved solids (TDS), rCl/rHCO 3 ratio, sodium adsorption ratio (SAR), groundwater type, hydraulic conductivity (K) and well discharge (Q). Weights have been assigned to all these layers according to their relative importance for groundwater vulnerability, whereas their corresponding normalized weights were obtained from their effectiveness factors. The groundwater vulnerability map indicates four classes ranging from very low to high. According to this map, the promising localities for groundwater usage are located in areas where very low to low vulnerability has been observed. These localities are distributed over 4080 Km 2 area, covering 53.68% of the total study area. The areas having moderate to high groundwater vulnerability are more than 3520 Km 2 , indicating a deterioration of groundwater quality in 46.32% of the study area, which need special treatment and cropping pattern before use.
Journal of King Saud University - Science
Journal of Volcanology and Geothermal Research, 2019
Wajid Formation is one of the most important waterbearing aquifers in the central part of Saudi A... more Wajid Formation is one of the most important waterbearing aquifers in the central part of Saudi Arabia. It consists from sandstone lithology of Lower Carboniferous age. Due to lack of drilling, the petrophysical characteristic of this aquifer is not clearly understood. The aim of this work is to study the petrophysical properties of Wajid Formation using the available well logging datasets. The analysis revealed the presence of three different zones. A middle zone consists mainly of shale with bad properties (low permeability < 0.002 mD; high shale > 95%; and very low effective porosity < 1%). Two overlying and underlying zones of good petrophysical characteristics (low shale < 10%; good effective porosity > 10% up to 16%) and fair to good permeability for the upper zone, 0.2 2.0 mD) and very good permeability (5.0 mD) for lower zone. Petrophysically, the lower zone is the best and we do recommend using it in water production and other purposes.
Journal of the Indian Society of Remote Sensing, 2015
ABSTRACT Geological and structural mappings of Tayyib Al-Ism area were carried out using the rock... more ABSTRACT Geological and structural mappings of Tayyib Al-Ism area were carried out using the rocks finite strain data, the Landsat-7 Enhanced Thematic Mapper Plus (ETM+) data and the field based observations. To analyze the finite strain in the studied rocks, the Rf /ϕ and Fry methods are applied to feldspar porphyroclasts and mafic grains from nine metavolcano-sedimentary samples (Hegaf Formation), four diorite-gabbros suite samples (Sawawin Complex), two meta-granite samples (Ifal suite) and five Zuhd alkali granite samples. The obtained data indicate traces of high to moderate level of deformation in the meta-granite and metavolcano-sedimentary rocks. The axial ratios along the XZ section range from 1.70 to 4.80 for the Rf/ϕ method and from 1.50 to 4.50 for the Fry method. A sub-vertical trend of short axes in association with sub-horizontal foliation is also observed. These informations allow us to conclude that a finite strain in the deformed granitic rocks is of the same order of magnitude as in the metavolcano-sedimentary rocks. The contacts between the metavolcano-sedimentary and granitic rocks in Tayyib al Ism area were formed during the granitic intrusions along some of the faults under brittle to semi-ductile deformation conditions. These faults have significantly influenced the geometry and style of rifting in the Red Sea during the Neogene. The finite strain was accumulated in the area during the process of deformation, which superimpose the already existed nappe structure. It indicates that the nappe contacts formed during the accumulation of finite strain. In addition to finite strain analysis, band ratio images (3/1, 5/3, 7/5) and Principal Component Analysis (PCA) technique have been used, which proved effective in mapping geological and structural features of various rock bodies exposed in the study area
Tectonophysics, 2013
The Atlas orogeny in northern Algeria and Tunisia led to the destruction of Tethys oceanic lithos... more The Atlas orogeny in northern Algeria and Tunisia led to the destruction of Tethys oceanic lithosphere and cumulated in a collision of microplates rifted off the European margin with the North African continental margin. The location of the boundary between African plate and Kabylian microplate is expressed in northern Algeria by a crustal wedge with double vergence of thrust sheets, whereas in northern Tunisia the geologic environment is more complex and the location of the plate boundary is ambiguous. In this study, we analyzed gravity data to constrain the crustal structure along the northern margin of Tunisia. The analysis includes a separation of regional and residual gravity anomalies and the application of gradient operators to locate density contrast boundaries. The horizontal gradient magnitude and directional gradient highlight a prominent regional E-W gravity gradient in the northern Tunisian Atlas interpreted as a deep fault (active since at least the Early Mesozoic) having a variable kinematic activity depending on the tectonic regime in the region. The main E-W gravity gradient separates two blocks having different gravitational and seismic responses. The southern block has numerous gravity lineaments trending in different directions implying several density variations within the crust, whereas the northern block shows a long-wavelength negative gravity anomaly with a few lineaments. Taking into account the geologic context of the Western Mediterranean region, we consider the E-W prominent feature as the boundary between African plate and Kabylian microplate in northern Tunisia that rifted off Europe. This hypothesis fits most previous geological and geophysical studies and has an important impact on the petroleum and mineral resource prospection as these two blocks were separated by an ocean and they did not belong to the same margin.
Journal of Coastal Research, 2014
A research project on the Saudi Gulf of Aqaba was initiated in January 2012 to evaluate, protect,... more A research project on the Saudi Gulf of Aqaba was initiated in January 2012 to evaluate, protect, and develop a proper management plan for sustainable use of water resources in the coastal region. Within the framework of this project, a total of 85 surface water samples was collected and investigated to document the surface distribution of the hydrographical parameters (including water temperature, salinity, density, hydrogen ion concentration, and dissolved oxygen) as well as concentration of the nutrient salts (ammonium, nitrite, nitrate, phosphate, and silicate). The results show no thermocline or thermal pollution in the studied water and that they are mostly well oxygenated. In addition, no significant variations in the pH and salinity values have been observed. Relatively low levels of nitrogen, phosphorus (in the dissolved and total forms), and reactive silicate are observed. Inorganic nitrogen is found in the order of NO 3-N. NO 2-N. NH 4-N. On the basis of the relatively low level of nutrient salts, the Gulf of Aqaba coastal water is classified as oligotrophic to mesotrophic in nature, and the study area is not yet seriously affected by contamination in spite of rapid population growth and fast infrastructural/recreational development during the past decade.
GEOPHYSICS, 1989
Until 216 vertical electrical Schlumberger soundings were made, little was known about the subsur... more Until 216 vertical electrical Schlumberger soundings were made, little was known about the subsurface geology at the Wadi Surdud area in the coastal plain of the Yemen Arab Republic. These soundings provide information on the distribution of aquifers, aquitards, and impermeable rocks, and the salinity of the groundwater. A first, qualitative interpretation of the geoelectrical sounding curves gives a general impression of the hydrogeologic setting and the aquifer boundaries. However, a more detailed, quantitative interpretation shows that no single resistivity model completely satisfies all the hydrogeologic and geologic facts and theories. Basically, two different models are possible: in one the thickness of the aquifer is fixed; in the other, its resistivity is fixed. Several geologic and hydrogeologic hypotheses may be put forward to support each model, varying from relying upon tectonic events and sedimentary depositional environments to influences of agriculture and water abstr...
Geochemistry, Geophysics, Geosystems, 2009
A global Earth Magnetic Anomaly Grid (EMAG2) has been compiled from satellite, ship, and airborne... more A global Earth Magnetic Anomaly Grid (EMAG2) has been compiled from satellite, ship, and airborne magnetic measurements. EMAG2 is a significant update of our previous candidate grid for the World Digital Magnetic Anomaly Map. The resolution has been improved from 3 arc min to 2 arc min, and the altitude has been reduced from 5 km to 4 km above the geoid. Additional grid and track line data have been included, both over land and the oceans. Wherever available, the original shipborne and airborne data were used instead of ...
Arabian Journal of Geosciences
critical economic and social significance to the region, where groundwater is the sole source of ... more critical economic and social significance to the region, where groundwater is the sole source of irrigation and drinking water. Evaluation of groundwater quality of the coastal aquifers revealed that groundwater salinization is widespread. Groundwater samples exceeded the permissible limits for the majority of drinking water parameters tested except for dissolved metals. The occurrence of very low trace element levels probably reflects natural sources. The distributions of total dissolved solids were found to vary spatially. The variability observed within the groundwater samples is primarily related to seawater intrusion, mineral dissolution in the aquifer, distance from the sea, solutes in recharging water, time of year. Wells located in the upper north part of the study area were highly contaminated compared to southern wells. In addition, the occurrence of high salinity in the northern wells may be the result of surface water flow direction, where leaching and runoff flushing through the basin occur. Saline groundwater might occur due to both high evaporation and dissolution of evaporate minerals. Nitrate concentrations are variable but showed elevated levels. Evaluation of usability of groundwater aquifer for irrigation revealed that the majority of wells are generally not suitable for irrigation use under normal conditions but rather for salt-tolerant plants or livestock watering.
Acta Geophysica, 2016
This study integrates potential gravity and magnetic field data with remotely sensed images and g... more This study integrates potential gravity and magnetic field data with remotely sensed images and geological data in an effort to understand the subsurface major geological structures in Afghanistan. Integrated analysis of Landsat SRTM data was applied for extraction of geological lineaments. The potential field data were analyzed using gradient interpretation techniques, such as analytic signal (AS), tilt derivative (TDR), horizontal gradient of the tilt derivative (HG-TDR), Euler Deconvolution (ED) and power spectrum methods, and results were correlated with known geological structures. The analysis of remote sensing data and potential field data reveals the regional geological structural characteristics of Afghanistan. The power spectrum analysis of magnetic and gravity data suggests shallow basement rocks at around 1 to 1.5 km depth. The results of TDR of potential field data are in agreement with the location of the major regional fault structures and also the location of the basins and swells, except in the Helmand region (SW Afghanistan) where many high potential field anomalies are observed and attributed to batholiths and near-surface volcanic rocks intrusions. STRUCTURAL INVESTIGATIONS OF AFGHANISTAN 979 A high-resolution airborne geophysical survey in the data sparse region of eastern Afghanistan is recommended in order to have a complete image of the potential field anomalies.