Essam Aboud | King AbdulAziz University (KAU) Jeddah, Saudi Arabia (original) (raw)
Papers by Essam Aboud
Annual Meeting of the Geological Society of Japan, 2005
Journal of African Earth Sciences, Nov 1, 2015
AGUFM, Dec 1, 2007
The diversity of volcanic rocks in the Cascadia forearc is well displayed in high-resolution aero... more The diversity of volcanic rocks in the Cascadia forearc is well displayed in high-resolution aeromagnetic data recently acquired over the Oregon Coast Range. The aeromagnetic survey extends from the Western Cascade Range to the continental shelf including the cities of Eugene and Florence, Oregon. Magnetic anomalies illuminate various geologic domains: (1) Numerous linear west-northwest-striking magnetic anomalies correspond in some places with mapped Oligocene and Eocene dikes and sills that intruded middle Eocene marine sedimentary rocks of the Tyee Formation. This pervasive linear pattern suggests that many similar dikes are concealed at shallow depth. (2) Arcuate, long-wavelength anomalies indicate folds within Eocene Siletz River Volcanics (SRV) lying beneath the Tyee Formation. (3) A pattern of short-wavelength anomalies is caused by Oligocene volcanic rocks of the Western Cascade Range. Superimposed on these anomaly patterns are linear, northeast-trending lineaments caused by various faults, including the Corvallis fault that juxtaposes SRV against Tyee Formation. To help differentiate these various magnetic signals, we have implemented a three-stage analysis. First, matched filters were designed to emphasize shallow magnetic sources. Second, a tilt-derivative (TDR) filter was applied to the shallow-source anomalies to distinguish noise from signal and map geologic contacts. Finally, an Euler analysis was applied using various structural indices to distinguish between dike and fault anomalies. This approach allows us to map both dikes and faults in detail, which is important since exposures are largely concealed in the heavily forested Coast Range. Modeling experiments indicate that we can detect dikes as thin as 25-75 m if they are separated by 1.5-2.5 km or more. In one case, a pair of WNW-striking magnetic anomalies overlies two separate mapped dikes, each about 25-75 m in thickness, 15 km long, and separated by 1.5 km. The magnetic doublet indicates that these two parallel dikes extend at least ~40-50 km and are offset approximately 1.5-2.0 km in two places by NNE-striking faults. We can resolve at least 40 sub- parallel, WNW-striking magnetic anomalies throughout the aeromagnetic survey. Assuming all of the WNW- striking linear anomalies are caused by dikes, and ignoring the possible presence of dikes thinner than our limits of resolution, we estimate that this episode of dike injection was accompanied by about 1 percent crustal extension. Taking into account 50° of clockwise rotation, the azimuth of maximum horizontal extension was 330°, approximately parallel to the Eocene convergent plate boundary.
66th EAGE Conference & Exhibition, 2004
P101 MAGNITUDE TRANSFORMS IN THE PROCESS OF MAGNETIC DATA ANALYSIS SUMMARY 1 The magnitude transf... more P101 MAGNITUDE TRANSFORMS IN THE PROCESS OF MAGNETIC DATA ANALYSIS SUMMARY 1 The magnitude transforms include magnitude magnetic anomalies (MMA) their gradients and Laplacian. They are calculable from the total magnetic anomalies (TMA) or other component anomalies. MMAs have space distribution different from that of the component anomalies. Their values are non-negative and the respective patterns are similar to the positive gravity anomalies. Thus a MMA from a compact source has only a maximum centered above the source. The sensitivity to the source magnetization direction is suppressed. The modulus of full gradients and Laplacian of MMAs are also non-negative space
Energies
We invert gravity and magnetic anomalies for basement relief at the Harrat Rahat Volcanic Field (... more We invert gravity and magnetic anomalies for basement relief at the Harrat Rahat Volcanic Field (HRVF) for the purpose of evaluating its geothermal energy prospects. HRVF is dominated by basaltic scoria cones and other volcanic rocks overlying the Proterozoic basement. The area considered for this study is located within the northern HRVF and consists mainly of alkali basalts with lesser amounts of benmoreite, mugearite, hawaiite, and trachyte. Our approach adopts a global optimization technique using Particle Swarm Optimization with automated parameter selection, and a two-dimensional gravity-magnetic (GM) forward modeling procedure. The results of the PSO-based approach indicate a depth to the basement at 0.10–624 m, with greater depths within the central region of a solitary anomalous density body in the HRVF. The obtained basement geometry is corroborated by the depth estimates obtained from other potential field inversion methods. The regions with higher prospects are mapped fo...
AGUSM, May 1, 2004
Esh El-Mallaha area is located on the western coast of the Gulf of Suez which is considered the m... more Esh El-Mallaha area is located on the western coast of the Gulf of Suez which is considered the main source of hydrocarbon resources in Egypt. The main exploration problem of the Gulf of Suez (and areas around) is the existence of the Pre-Miocene salt that masks the seismic energy and as a result, seismic method is not usually able to
Earth, Planets and Space, Aug 1, 2005
ASEG extended abstracts, Dec 1, 2012
Earth, Planets and Space, Aug 1, 2005
Journal of African Earth Sciences
72nd EAGE Conference and Exhibition incorporating SPE EUROPEC 2010, 2010
The Extended Tilt-depth method builds on the existing Tilt-depth method to remove one of its cons... more The Extended Tilt-depth method builds on the existing Tilt-depth method to remove one of its constraints - that of relying on the source model being a vertical contact. To achieve this, there is a need to go to the tilt of the local wavenumber, a second order derivative which is independent of structural index. The Extended Tilt-depth method is thus a new interpretation tool for the initial evaluation of high resolution aeromagnetic survey data. The method is tested using a theoretical model and a field example from the North Western Desert of Egypt. In the former, the method estimated the correct depth for the model. For the field data, The Extended Tilt-depth method successfully identifies a number of important tectonic elements known from geologic mapping and known areas of sedimentary basins. Further testing and application of this new method, using known models and field examples, is needed to fully appreciate its strengths and weaknesses.
Social Science Research Network, 2022
Proceedings, 2013
Two geothermal fields in Costa Rica were investigated by gravity surveys in an attempt to delinea... more Two geothermal fields in Costa Rica were investigated by gravity surveys in an attempt to delineate their subsurface structures. The surveys improve the understanding of the relation between the geothermal systems and subsurface structure. The gravity data are analyzed using integrated gradient interpretation techniques such as the Horizontal Gradient (HG) and Euler Deconvolution methods. With these techniques, many faults are detected and compared with those found in the surface geology. The results of this study lead to a better understanding of the geothermal system in the study area and may aid in future geothermal exploration.
Journal of Asian Earth Sciences, Oct 1, 2016
Journal of Applied Geophysics, Dec 1, 2018
Arabian Journal of Geosciences, Mar 3, 2011
Mount Ungaran is a Quaternary volcano located in the province of Central Java, Indonesia. The stu... more Mount Ungaran is a Quaternary volcano located in the province of Central Java, Indonesia. The study area was covered by a gravity survey in order to delineate the subsurface structure and its relation to the hot springs that are spread throughout the area. The gravity data were analyzed using gravity gradient interpretation techniques, such as the horizontal gradient and Euler
Annual Meeting of the Geological Society of Japan, 2005
Journal of African Earth Sciences, Nov 1, 2015
AGUFM, Dec 1, 2007
The diversity of volcanic rocks in the Cascadia forearc is well displayed in high-resolution aero... more The diversity of volcanic rocks in the Cascadia forearc is well displayed in high-resolution aeromagnetic data recently acquired over the Oregon Coast Range. The aeromagnetic survey extends from the Western Cascade Range to the continental shelf including the cities of Eugene and Florence, Oregon. Magnetic anomalies illuminate various geologic domains: (1) Numerous linear west-northwest-striking magnetic anomalies correspond in some places with mapped Oligocene and Eocene dikes and sills that intruded middle Eocene marine sedimentary rocks of the Tyee Formation. This pervasive linear pattern suggests that many similar dikes are concealed at shallow depth. (2) Arcuate, long-wavelength anomalies indicate folds within Eocene Siletz River Volcanics (SRV) lying beneath the Tyee Formation. (3) A pattern of short-wavelength anomalies is caused by Oligocene volcanic rocks of the Western Cascade Range. Superimposed on these anomaly patterns are linear, northeast-trending lineaments caused by various faults, including the Corvallis fault that juxtaposes SRV against Tyee Formation. To help differentiate these various magnetic signals, we have implemented a three-stage analysis. First, matched filters were designed to emphasize shallow magnetic sources. Second, a tilt-derivative (TDR) filter was applied to the shallow-source anomalies to distinguish noise from signal and map geologic contacts. Finally, an Euler analysis was applied using various structural indices to distinguish between dike and fault anomalies. This approach allows us to map both dikes and faults in detail, which is important since exposures are largely concealed in the heavily forested Coast Range. Modeling experiments indicate that we can detect dikes as thin as 25-75 m if they are separated by 1.5-2.5 km or more. In one case, a pair of WNW-striking magnetic anomalies overlies two separate mapped dikes, each about 25-75 m in thickness, 15 km long, and separated by 1.5 km. The magnetic doublet indicates that these two parallel dikes extend at least ~40-50 km and are offset approximately 1.5-2.0 km in two places by NNE-striking faults. We can resolve at least 40 sub- parallel, WNW-striking magnetic anomalies throughout the aeromagnetic survey. Assuming all of the WNW- striking linear anomalies are caused by dikes, and ignoring the possible presence of dikes thinner than our limits of resolution, we estimate that this episode of dike injection was accompanied by about 1 percent crustal extension. Taking into account 50° of clockwise rotation, the azimuth of maximum horizontal extension was 330°, approximately parallel to the Eocene convergent plate boundary.
66th EAGE Conference & Exhibition, 2004
P101 MAGNITUDE TRANSFORMS IN THE PROCESS OF MAGNETIC DATA ANALYSIS SUMMARY 1 The magnitude transf... more P101 MAGNITUDE TRANSFORMS IN THE PROCESS OF MAGNETIC DATA ANALYSIS SUMMARY 1 The magnitude transforms include magnitude magnetic anomalies (MMA) their gradients and Laplacian. They are calculable from the total magnetic anomalies (TMA) or other component anomalies. MMAs have space distribution different from that of the component anomalies. Their values are non-negative and the respective patterns are similar to the positive gravity anomalies. Thus a MMA from a compact source has only a maximum centered above the source. The sensitivity to the source magnetization direction is suppressed. The modulus of full gradients and Laplacian of MMAs are also non-negative space
Energies
We invert gravity and magnetic anomalies for basement relief at the Harrat Rahat Volcanic Field (... more We invert gravity and magnetic anomalies for basement relief at the Harrat Rahat Volcanic Field (HRVF) for the purpose of evaluating its geothermal energy prospects. HRVF is dominated by basaltic scoria cones and other volcanic rocks overlying the Proterozoic basement. The area considered for this study is located within the northern HRVF and consists mainly of alkali basalts with lesser amounts of benmoreite, mugearite, hawaiite, and trachyte. Our approach adopts a global optimization technique using Particle Swarm Optimization with automated parameter selection, and a two-dimensional gravity-magnetic (GM) forward modeling procedure. The results of the PSO-based approach indicate a depth to the basement at 0.10–624 m, with greater depths within the central region of a solitary anomalous density body in the HRVF. The obtained basement geometry is corroborated by the depth estimates obtained from other potential field inversion methods. The regions with higher prospects are mapped fo...
AGUSM, May 1, 2004
Esh El-Mallaha area is located on the western coast of the Gulf of Suez which is considered the m... more Esh El-Mallaha area is located on the western coast of the Gulf of Suez which is considered the main source of hydrocarbon resources in Egypt. The main exploration problem of the Gulf of Suez (and areas around) is the existence of the Pre-Miocene salt that masks the seismic energy and as a result, seismic method is not usually able to
Earth, Planets and Space, Aug 1, 2005
ASEG extended abstracts, Dec 1, 2012
Earth, Planets and Space, Aug 1, 2005
Journal of African Earth Sciences
72nd EAGE Conference and Exhibition incorporating SPE EUROPEC 2010, 2010
The Extended Tilt-depth method builds on the existing Tilt-depth method to remove one of its cons... more The Extended Tilt-depth method builds on the existing Tilt-depth method to remove one of its constraints - that of relying on the source model being a vertical contact. To achieve this, there is a need to go to the tilt of the local wavenumber, a second order derivative which is independent of structural index. The Extended Tilt-depth method is thus a new interpretation tool for the initial evaluation of high resolution aeromagnetic survey data. The method is tested using a theoretical model and a field example from the North Western Desert of Egypt. In the former, the method estimated the correct depth for the model. For the field data, The Extended Tilt-depth method successfully identifies a number of important tectonic elements known from geologic mapping and known areas of sedimentary basins. Further testing and application of this new method, using known models and field examples, is needed to fully appreciate its strengths and weaknesses.
Social Science Research Network, 2022
Proceedings, 2013
Two geothermal fields in Costa Rica were investigated by gravity surveys in an attempt to delinea... more Two geothermal fields in Costa Rica were investigated by gravity surveys in an attempt to delineate their subsurface structures. The surveys improve the understanding of the relation between the geothermal systems and subsurface structure. The gravity data are analyzed using integrated gradient interpretation techniques such as the Horizontal Gradient (HG) and Euler Deconvolution methods. With these techniques, many faults are detected and compared with those found in the surface geology. The results of this study lead to a better understanding of the geothermal system in the study area and may aid in future geothermal exploration.
Journal of Asian Earth Sciences, Oct 1, 2016
Journal of Applied Geophysics, Dec 1, 2018
Arabian Journal of Geosciences, Mar 3, 2011
Mount Ungaran is a Quaternary volcano located in the province of Central Java, Indonesia. The stu... more Mount Ungaran is a Quaternary volcano located in the province of Central Java, Indonesia. The study area was covered by a gravity survey in order to delineate the subsurface structure and its relation to the hot springs that are spread throughout the area. The gravity data were analyzed using gravity gradient interpretation techniques, such as the horizontal gradient and Euler