National Research Institute of Astronomy and Geophysics, Cairo, Egypt
eaboud@gmail.com
Essam Aboud Associate professor, National Research Institute of Astronomy and Geophysics, Helwan, Cairo, Egypt
received a B.Sc. (1992) in geophysics from Cairo University, M.Sc. in geophysics from Cairo University and a PhD (2005) from Kyushu University, Japan in potential field Geophysics. Awarded a PostDoc (2007) at the US Geological Survey (USGS).
Currently: Ass. Prof. GeoHazards Research Unit, Faculty of Earth Sciences, King Abdulaziz University, PO. Box 80206, Jeddah 21589, Saudi Arabia
Abstract: The Aluto-Langano geothermal field is located in the central southern
portion of Ethiopia within the Ethiopian Rift Valley. The gravity of
the area was surveyed in an attempt to delineate the subsurface structure
and to better understand the relationship between the geothermal systems
and the subsurface structure. The gravity data were analyzed using integrated
gradient interpretation techniques, such as the Horizontal Gradient
(HG), Source Edge Detection (SED), and Euler Deconvolution (ED)
methods. These techniques detected many faults that were compared
with the mapped faults in the surface geology. The results of the present
study will lead to an improved understanding of the geothermal system in
the study area and aid the future geothermal exploration of the area.
Abstract: The present study is an attempt to determine the sedimentary cover, and structural trends in the central
part of Sinai Peninsula, Egypt. This study has been implemented by the integration of gravity and magnetic
methods. Gravity data has been used for 2D modelling along some profiles perpendicular to the
main structural trends of the study area. Magnetic data will be analyzed to determine the depth to the
basement surface. The depths obtained from magnetic data will be used as a control points in the gravity
modelling in order to minimize the error and facilitate the iteration of the suggested models. The basement
relief map from magnetic and gravity output has been produced. This map indicates that, the basement
depths, generally, increases from south to north and from east to west direction of the study area.
The sedimentary cover is about 1.5–2 km in the southern part and increases to more than 4 km in the
northeastern and western parts and changes gradually in the other parts of the study area. Results of
structural trend analysis indicate that, the study area is greatly affected by several structural trends;
N–S, E–W, NW–SE, and NNE–SSW directions. These trends are associated with the Baltim fault trend,
Tethyan trend, Gulf of Suez, and Aqaba trend, respectively
Abstract: In this work, we used seismic refraction and magnetic methods to find the extension of a known subsurface fault and delineate for the existence of many others. Combination of both seismic refraction and magnetic method give a better subsurface view, where both seismic and magnetic methods can detect fault locations; however, fault thrown and subsurface layering will be better detected by seismic method, while magnetic method will provide a better lateral view of the faulting system in the study area. Seismic
refraction shows that at least two fault plans exist in the subsurface; magnetic results supported seismic results and suggested the existence of several small fault plans in the study area.
Abstract: There is a clear correlation between the principal areas of current
geothermal development and the seismically active boundaries of the
moving segments of lithosphere defined by the plate tectonic models of the
Earth. The tectonic position of Egypt in the northeastern corner of African
continent suggests that the most important areas for geothermal exploration
are in the region where a cluster of hot springs with varied temperatures was located around the Gulf of Suez. Gravity and magnetotelluric surveys were made in the area of Hammam Faraun hot spring, which represents the most promising area for geothermal development in Egypt. These surveys were carried out for the purpose of eliciting the origin of Hammam Faraun hot spring. The results of the analyses and interpretations of these data show
that the heat source of the hot spring is due to uplift of hot basement rock.
This uplift may cause deep circulation and heating of the undergroundwater.
Abstract: Sinai Peninsula is considered as a unique region in the world due to its geographical location, tectonic and
thermal activities. It is located geographically at the crossroads of Europe, Asia, and Africa constituting a triple
junction point between the three continents. It is also characterized by thermal manifestations represented by
several hot springs with varied temperatures (30–70 °C). Most of these hot springs are located along the
shoreline of the Gulf of Suez.
In this study, we aim to map the Curie depth isotherm surface for Sinai Peninsula based on the analysis of
ground magnetic data. Spectral analysis technique will be used to estimate the boundaries (top and bottom)
of the magnetized crust. The depths obtained for the bottom of magnetized crust are assumed to correspond
to Curie point depths where the magnetic layer loss its magnetization.
Results of this study indicate that the shallow Curie depths (~15–18 km) are located at the southern part of
Sinai Peninsula and along the shoreline of the Gulf of Suez and depths increase (22–25 km) towards the
central and north western portions of Sinai Peninsula. The whole average Curie depth point of Sinai Peninsula
is about 20 km. Generally, the shallow depths to Curie isotherm indicate that Sinai Peninsula is a promising
area for further geothermal exploration particularly near the eastern side of the Gulf of Suez.
Abstract: 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 deconvolution methods, and many faults were detected. The results of the present study suggest that the hot springs around Ungaran Volcano are structurally controlled and have depths ranging from 1 to 3 km. The results of the present study lead to an understanding of the relationships between the interpreted faults and the locations of hot springs and may aid in future geothermal exploration of the area.
Abstract: The Hammam Faroun has a particular importance due to its geothermal activity which constitutes the main
geothermal resource of Egypt. The area is located on the Sinai Peninsula, a subplate bounded by two seismically active
structural zones along the Gulf of Suez and Gulf of Aqaba. High-resolution ground-based gravity and magnetic data are
available for the entire Hammam Faroun area, acquired as part of a national project to explore for mineral, geothermal, and hydrocarbon resources. Gravity and magnetic data were analyzed using Source Edge Detection and Source Parameter Imaging (SPI) techniques to image subsurface structures. These analyses show that the area is characterized by a set of northwest-striking faults lying parallel to the Gulf of Suez. Orthogonal patterns are also present, possibly related to rifting of the Gulf of Suez. Depth analysis using the SPI method indicates that surface faults extend to 5-km depth. Analysis of
potential-field data elucidates the structurally complex subsurface
structure of the Hammam Faroun area.
Abstract: The present work deals with the integration of remote-sensing, surface-geology and gravity-survey data to improve the structural knowledge of the Tarhunah area, northwest Libya. Geological information and remote-sensing data provided information about the surface structure. A gravity survey was conducted to decipher the subsurface structure. The results revealed that a basin having a width of 39 to 48 km trends NE. A two-dimensional (2-D) schematic model shows that the basin gradually deepens toward the southwest. Faults determined from a horizontal gradient, tilt derivative, and Euler deconvolution show a depth range of 2.5 to 7.5 km. The integration and interpretation of the results indicate that volcanic activity was related to the tectonic activity of an anticlinal structure called the Jabal Uplift.
Abstract: We used an integrated approach to constrain the geological structure of the Jifara Plain in northwest Libya. The analysis
of surface data, including a digital elevation model (DEM), Landsat Enhanced Thematic Mapper Plus images, and geologic maps, was combined with subsurface data, including well logs and magnetic data. The DEM data were used for the identification of geological lineaments in the study area. The interpretation and analysis of the lineaments indicate that the Jifara Plain is controlled by three main fault systems, trending northwest–southeast, east–west, and northeast–southwest. The three trends represent the remnants of reactivated structures that formed under the stress regimes generated during the tectonic evolution of North Africa. The magnetic data reveal three northwest- and northeasttrending sedimentary basins in the study area. The depth of the basement inside the main basin ranges from 1 to 5 km. The results indicate that the Jifara Basin is shallower than the surrounding basins. The integration of the results reflects different periods
of tectonic activity in the Jifara Plain and the adjacent Jabal Nafusah.
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: The Obama geothermal field is located on the western part of Kyushu Island, Japan. This area has importance
due to its high geothermal content which attracts sporadic researchers for study. In 2003 and 2004, Obama was
covered by gravity surveys to monitor and evaluate the geothermal field. In this paper, the surveyed gravity data
will be used in order to delineate and model the subsurface structure of the study area. Gradient methods such
as analytic signal and vertical derivatives were applied to the gravity data. The available borehole data and the
results of the gradient interpretation techniques were used to model the Obama geothermal field. In general, the
obtained results show that the gradient interpretation techniques are useful to obtain geologic information from
gravity data.
Abstract: In this work, we use the magnetotelluric (MT) method to detect geoelectrical conductivity anomalies in the Earth’s crust and
link them to local seismic activity. This application affords the unusual opportunity to study the percolation of water from a lake into a fault system and its effect on the induced seismicity. MT measurements were carried out in the period range 0.0046–420 s at nine sites along a 15 km-long North–South profile crossing the Kalabsha Fault, on the western bank of Lake Aswan. Data were analysed by 2D simultaneous inversion of both polarisations. The resulting model is compared with the local seismicity map and reveals the conductive signature of the fault, as well as geological and tectonic stresses prevailing in the Aswan area. Our MT investigations show the following features: The measured MT strike aligns with the seismic epicentre axis corresponding to the Kalabsha Fault. While crossing the Fault, enhanced conductivity is found down to depths of 5 km on a 1–2 km profile segment. At mid-crustal depths (20 km), a very high conductive body is found to coincide with the main seismic cluster in the Aswan area. These observations indicate that seismic activity and high electrical conductivity are related. The link between them is the presence of crustal fluids which are presumably the cause of the high conductivity observed. Their presence is also required to trigger the observed seismicity. In addition, we explain the lower conductivity of the local upper crust in terms of stress-modulated rock porosity. We believe that these results are of general significance, as they could explain the mid-crustal seismicity of tectonically active zones.
Abstract: The Gebel El-Zeit area is located on the western coast of the Gulf of Suez, Egypt. The areas in/and around the
Gulf of Suez are generally important due to their hydrocarbon resources. In this study, we have applied gradient
interpretation techniques (Euler deconvolution and analytic signal) to the aeromagnetic data of the Gebel El-Zeit
area. The main objective of this study is to identify and delineate the possible subsurface structure of the area that
may assist in locating new hydrocarbon prospects. Results of Euler method suggested that, on the eastern and
western parts of the area, the basement could be observed on the ground (∼50 m over the ground) and became
more deeper on the central part to reach depth of 5 km (from the ground level). Results from the analytic signal
method indicated that, the depth to the basement has an average value of 156 m on the eastern side and 758 m on
the western side. Generally, the area is characterized by a graben structure bounded by major faults striking in
the NW-SE direction.
.
Abstract: Exploration in the northern Red Sea of Egypt has had little success in locating hydrocarbon accumulation.
The main exploration problems in this region are the complex block faulting and Miocene salt structures. The
complex basement block structure arises from the different ages of faults and the difficulty of determining the
exact age relations. In this paper, we present a case study of structural mapping using application of the Euler
method to high-resolution aeromagnetic data collected in the Quseir area of the northern Red Sea of Egypt. The
results indicated that the area is affected by sets of fault systems, which are mainly trending in the NNW-SSE,
NW-SE and NE-SW directions. The results also delineated boundaries of a long and wide magnetic body on the
offshore part of the study area. This basement intrusion is most probably related to the Red Sea rift and perhaps
associated with structures higher up in the sedimentary section. As a result, the area above this anomaly is highly
recommended for further oil exploration. This example illustrates that high-resolution aeromagnetic surveys can
help greatly in delineating subsurface structure in the northern Red Sea of Egypt.
Abstract: An intensive geophysical study has been performed for hot spring, central Sinai, in order to illustrate the
role of magnetic and magnetotelluric interpretation in the detection of the major subsurface structural elements
affecting both the sedimentary section and the underlying basement complex. More attention was given to the
hot spring to spot more light on the subsurface structural features that control the occurrence of this spring. For
that, five magnetotelluric (MT) stations have been carried out with about 5.0 km distance. Magnetotelluric
components (Hx, Hy, Hz, Ex and Ey) have been recorded simultaneously. According to the magnetotelluric
results, the area is tectonically active and there is a conductive anomaly situated just beneath the hot spring at a
depth of 2.0 km. The modeling revealed that, a possible connection between this anomaly and the conductive
sediments, which can be considered as the source of the phenomena.
A detailed land magnetic survey was carried out along several profiles crossing the hot spring. The
necessary reduction concerning the daily variation, the regional gradient and the time variation were applied,
and then the total intensity anomaly map was constructed. This step was followed by application of the filtered
and 3-D Euler deconvolution techniques. The results of magnetic interpretation revealed that, the hot spring is
tectonically controlled by faulting having a major NW-SE alignment and extends to a depth of about 2.0 km.
The strong magnetic anomalies surrounding the hot spring can be attributed to the occurrence of subsurface
basic intrusion of high magnetic contents. Also the study revealed that, the area has been affected by two main
tectonic trends having the directions NE-SW and NW-SE. The depth estimation to the basement complex
indicated that, it ranges between 1.0 and 2.0 km, and volcanic basaltic intrusions & dykes may occur between
400 and 600 m.
Abstract: Hohi area is located in central Kyushu island of Japan and is known as a volcano-tectonic depression region. The area
is characterized by its potential geothermal resources. In this study, we attempt to delineate the subsurface structures
of the area using integrated interpretation of existing gravity data. The gravity survey of Hohi area is about 500 km2. The
total number of gravity stations was up to 1500 and average distribution of stations was approximately 3 per km2.
Interpretation of horizontal gradient of the gravity data indicated that the area is characterized by the existence of
high gradient anomalies associated with existing geothermal fields and manifestations. Horizontal gradient
analysis also enabled tracing several faults that are mainly striking in the S-N, NW-SE, and NE-SW directions. Euler
deconvolution method has been applied to the gravity data and provided fast information about both the depth and
trends of the shallower subsurface structures in the area. Depth to deeper structures, based on modeling of the
gravity data, is found to be about 5.4 km.
Abstract: Sinai Peninsula is characterized by superficial thermal manifestations represented by a cluster of hot springs with
varied temperatures (30-72°C). These springs are mostly issue out of fractures and distributed along the Eastern
shore of the Gulf of Suez. In this work, we present a reconnaissance study to elucidate the geothermal resources
and delineate the structural setting of the area using available geophysical data; including heat flow, geothermal
logs, geoelectrical resistivity and aeromagnetic data. The heat flow and geothermal well logging measurements
showed that the eastern part of the peninsula is characterized by a high heat flow with an average value of
70mW/m2. Geoelectrical resistivity surveys were conducted in terms of Vertical Electrical Soundings (VES) at some
localities nearby the surface thermal manifestations. The resulted geoelectrical cross sections delineated the
subsurface structure at the studied localities and gave an explanation for the hot water source. Interpretation of
magnetic data indicated that the hot springs in the western side of the peninsula are structurally controlled.
Additionally, the calculated depth to Curie point isotherm ranges between 6.2 and 19.7 Km. Generally, the results
indicate that Sinai Peninsula is a promising for further geothermal exploration.
Abstract: Significant improvements in the magnetic
survey, design, processing and most
important, resolution of aeromagnetic data
could provide detailed information on the
spatial distribution, geometry, and structural
style of faults and fracture systems. The
magnetic data can easily integrate/merge and
correlated with other available data (e.g.
gravity, geology, seismic, topography). The
integration of these data provides an
excellent approach for structural system and
evaluation of hydrocarbon plays in Esh El
Mellaha area, Gulf of Suez. In this paper,
enhancements and filtering of aeromagnetic
data were implemented using band-pass
filter and horizontal gradient technique. The
results are compared with the available
information; such as geologic map, drill-hole
data, topographic data, and 2D seismic data
in the northern part of the area. In general,
the area is dissected by a system of faults
most of them trending in the NW-SE (Red
Sea trend) and NEE-SWW (Tethyan trend).
Abstract: Esh El-Mallaha area has a great importance due to its location on the western flank of the Gulf of Suez, Egypt. Areas around the Gulf of Suez represent potential prospects for hydrocarbon resources. However, seismic exploration in the area has had a little success in locating hydrocarbon resources. The main exploration problem is the basement complex structure characterizing the study area.
In this study, we attempt to image the subsurface structure of the area using interpretation of magnetic data based on Euler method. We have applied Euler method to the total
Abstract: Geophysical technologies provide subsurface imaging that is used in a variety of field applications. Imaging the subsurface structure of the earth is considered the main
objective in earth resources exploration. However, achieving this target is required using several exploration methods such as seismic, gravity, magnetic. Each method has its
special criteria making it in advance with respect to the other. For example; magnetic method is considered the faster one and can be used to cover a wide area in a short time. In
this study, magnetic interpretation methods are investigated. In order to interpret the magnetic data, gradient interpretation techniques (Euler deconvolution and analytic signal) were studied. These methods have advantages making them in advance with respect to the others. First, they do not need any priori geologic information and cab be applied with few assumptions. Second, they are not affected with the direction of the magnetic field which is very important factor in magnetic exploration. Moreover, these methods have found a broad range of applications in various exploration fields. Euler deconvolution is usually applied to the total magnetic-field data to estimate the depth and location of the magnetic sources. Herein, Euler deconvolution method will
be applied to the total field as well as to its components (regional and residual) in an attempting to obtain new information for exploration purposes. On the other hand, analytic
signal method is used to locate the geological boundaries from magnetic data. This technique will be applied to the magnetic data. New depth estimation method derived form
the analytic signal will be also used to estimate the depths of these geologic boundaries. Results of Euler deconvolution indicated that the surface geology faults have
vertical extension into the subsurface which means that the application of Euler method to the field and its components add new geologic information assist in imaging the subsurface
structure. Results of the analytic signal method imaged successfully the sedimentary basin and the results of the application of the new depth estimation method were well agreed
with the available geologic information which proves the effectiveness of the proposed depth estimation method.
Abstract: Improving knowledge of the geology and geophysics of the Arbuckle Uplift in south-central Oklahoma is a goal of the Framework Geology of Mid-Continent Carbonate Aquifers project sponsored by the United States Geological Survey (USGS) National Cooperative Geologic Mapping Program (NCGMP). In May 2007, we collected ground magnetic and gravity observations in the Hunton Anticline region of the Arbuckle Uplift, near Sulphur, Oklahoma. These observations complement prior gravity data collected for a project sponsored by the National Park Service and helicopter electromagnetic (HEM) and aeromagnetic data collected in March 2007 for the NCGMP project. This report describes the instrumentation and processing that was utilized in the May 2007 geophysical fieldwork, and it presents preliminary results as gravity anomaly maps and magnetic anomaly profiles. Digital tables of gravity and magnetic observations are provided as a supplement to this report. Future work will generate interpretive models of these anomalies and will involve joint analysis of these ground geophysical measurements with airborne and other geophysical and geological observations, with the goal of understanding the geological structures influencing the hydrologic properties of the Arbuckle-Simpson aquifer.
