Geophysical site assessment of an active urban development site, southeastern suburb of Cairo, Egypt

There has been significant structural damage of newly built residential buildings in Quarter-27 District in the SE of Cairo, Egypt. A nearby active limestone quarry may also be affecting ground stability. This paper shows how a near-surface geophysical survey could characterize the site, unusually after the initial housing construction had already been undertaken. Geophysical surveys included seismic refraction (acquired between phases of quarry blasting), electrical resistivity and ground penetrating radar (GPR) 1D and 2D datasets. Geophysical results produced maps of a 3D ground model that also included water table depth, known major faults and a saturated layer that may have caused the building damage. Of the geophysical techniques trialled electrical resistivity tomography and GPR data were deemed optimal. This study shows that it is possible to undertake geophysical surveys to characterize a restricted urban site development.

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Geostatistical simulation for geophysical applications—Part II: Geophysical modeling

Geophysics ◽

10.1190/1.1442791 ◽

1990 ◽

Vol 55 (11) ◽

pp. 1441-1446 ◽

Cited By ~ 2

Author(s):

P. N. Shive ◽

T. Lowry ◽

D. H. Easley ◽

L. E. Borgman

Keyword(s):

Physical Properties ◽

Seismic Velocity ◽

Seismic Refraction ◽

Three Dimensional ◽

Companion Paper ◽

Geostatistical Simulation ◽

Near Surface ◽

Geophysical Modeling ◽

Karst Environment ◽

Geophysical Surveys

A companion paper (this issue) describes a method for producing three‐dimensional simulations of physical properties for different geologic situations. Here we create a simulation for a particular case, which is a near‐surface (<80 ft deep) description of a karst environment. We simulate seismic velocity, density, resistivity, and the dielectric constant for this situation. We then conduct (in the computer) hypothetical geophysical surveys at the surface of the model. These surveys are seismic refraction, microgravity, dc resistivity, and ground‐probing radar. Physical properties appropriate for cavities are then entered in the model. Repeating the geophysical surveys over the model with cavities provides a convenient method of evaluating their potential for cavity detection. Anomalies produced by normal variations in physical properties may simulate or obscure anomalies from target features. More data about the correlation of physical properties, particularly in the horizontal directions, will be required to evaluate this problem properly.

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Détermination de la géométrie et des propriétés physiques du pergélisol discontinu de la région de Schefferville

Canadian Journal of Earth Sciences ◽

10.1139/e77-043 ◽

1977 ◽

Vol 14 (3) ◽

pp. 431-443 ◽

Cited By ~ 1

Author(s):

Maurice K.-Seguin

Keyword(s):

Electrical Resistivity ◽

Regional Scale ◽

Seismic Refraction ◽

Geophysical Methods ◽

Near Surface ◽

Vertical Extension ◽

Discontinuous Permafrost ◽

Propriétés Physiques ◽

Lower Limits

The various parameters used to predict on a regional scale the lateral and vertical extension of permafrost are the following: surface temperature, thermal conductivity of rocks, and geothermal flow configuration. Locally this type of data is generally not sufficient and far too inaccurate. The use of geophysical methods at the surface and in boreholes in addition to existing thermal data helps to improve the degree of accuracy in the prediction of spatial distribution of permafrost in a given area. These geophysical methods include seismic refraction, electrical resistivity, and spontaneous and induced polarizations.Because of the properties of permafrost, seismic refraction at surface is useful only to determine the top of the permafrost whereas electrical resistivity (electric logging near surface) allows the determination of the upper and lower limits of permafrost. Seismic refraction, resistivity, and spontaneous and induced polarizations in boreholes were deemed more promising to determine masses or lenses of permafrost.Moreover, it was possible to correlate temperature and electrical resistivity measurements in boreholes, thus allowing the drawing of isothermal curves from electric logging in areas of continuous and discontinuous permafrost, at least when it is 'marginal'.The data for this study were obtained from the experimental station at Schefferville, Québec. [Journal Translation]

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Foundation Evaluation of a Repeater Installation Building using Electrical Resistivity Tomography and Seismic Refraction Tomography

Journal of Environmental and Engineering Geophysics ◽

10.2113/jeeg24.1.27 ◽

2019 ◽

Vol 24 (1) ◽

pp. 27-38

Author(s):

B. Butchibabu ◽

Prosanta K. Khan ◽

P.C. Jha

Keyword(s):

Electrical Resistivity ◽

Electrical Resistivity Tomography ◽

Seismic Refraction ◽

P Wave ◽

S Wave ◽

Resistivity Tomography ◽

Near Surface ◽

Refraction Tomography ◽

Subsurface Layers ◽

Geophysical Investigations

Geophysical investigations were carried out for evaluation of damage and to assess the possible causes for repeated occurrence of damage at one of the buildings constructed for oil pumping in the northern part of India. Electrical Resistivity Tomography (ERT) and Seismic Refraction Tomography (SRT) techniques were adopted for studying the subsurface of the area around the building with an objective of ascertaining the cause of damage. High resolution imaging was done using both the techniques in this investigation. ERT delineated the presence of low resistivity (2 ohm-m) water filled voids below the structures and mapped different subsurface layers such as sandy soil, clay and sandstone in the study area. SRT revealed P-wave velocity ( V P ) of the subsurface medium in the range of 400–3,400 m/s. Corresponding densities and S-wave velocities ( V S ) were determined based on Gardner's and Castagna's relationships. Subsequently, the V P , V S and the modulus values were used in estimating compressibility of soil and rock strata. Results showed near surface layers were characterized by high compressibility (26.673 × 10 −5 Pa −1 ), decreases with depth. This paper presents the details of the site, techniques used in the investigation and correlation of geophysical results with lithological information, and the subsequent analysis for understanding the distress in the subsurface of the study area.

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Multidisciplinary Approach to a Recovery Plan of Historical Buildings

International Journal of Geophysics ◽

10.1155/2011/258043 ◽

2011 ◽

Vol 2011 ◽

pp. 1-12 ◽

Cited By ~ 1

Author(s):

Luciana Orlando

Keyword(s):

Electrical Resistivity ◽

Seismic Data ◽

Electrical Resistivity Tomography ◽

Multidisciplinary Approach ◽

Seismic Refraction ◽

Lateral Velocity ◽

Resistivity Tomography ◽

Multiple Data ◽

Geophysical Surveys ◽

Joint Interpretation

The paper emphasizes the advantages of employing multiple data techniques—geology, GPS, surveys of cracking, boreholes, seismic refraction and electrical resistivity tomography—to image the shallow stratigraphy and hypothesize the cause of instability of an urban area. The study is focused on the joint interpretation of the crack pattern, topographic monitoring and the features of the underground, to define the area affected by instability and the direction of ground motion with the objective to advance a hypothesis on the cause of the instability of the area and to depict the main features. Borehole stratigraphies for a univocal interpretation of the lithology of electrical and seismic data and electrical resistivity tomography to constrain the interpretation of the lateral velocity variations and thickness of seismic bedrock were used. The geophysical surveys reveals to be complementary in the depicting of underground features. The study is approached at small and medium scale.

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GEOELECTRICAL SIGNATURES AND THEIR RELATIONSHIPS WITH THE LATERITIC HORIZONS: A CASE STUDY OF THE N4EN MINE’S IRON CAVE, CARAJÁS COMPLEX, BRAZIL

Brazilian Journal of Geophysics ◽

10.22564/rbgf.v37i4.2013 ◽

2019 ◽

Vol 37 (4) ◽

pp. 235

Author(s):

GUILHERME A. S. PROSDOCIMI ◽

MARCO A. DA S. BRAGA ◽

MARCELO R. BARBOSA ◽

IURI VIANA BRANDI

Keyword(s):

Electrical Resistivity ◽

Well Logging ◽

Near Surface ◽

Applied Geophysics ◽

Geophysical Surveys ◽

Iron Mine ◽

Northern Brazil ◽

Iron Formations ◽

Lateritic Profile

ABSTRACT The Brazilian speleological heritage is protected by laws, and every region where caves are present requires scientific studies to assist in environmental licensing. In the context of mining in iron formations, the near-surface geophysical studies using electroresistivity survey were performed in the cave N4E-0022, located at the N4EN iron mine, Carajás Complex, northern Brazil. The near-surface geophysical surveys generated continuous images that enhanced the lithostructural mapping of the lateritic profile, especially in places to which access by conventional methods was difficult. The electrical resistivity profiles were acquired with the dipole-dipole arrangement in the upper portion of the cave. Three sections were performed in SW-NE direction and two in SE-NW direction, totaling 435 meters of acquisition. The geoelectrical signatures were correlated with the lithologic logs of drillholes, the geophysical well logging and with the typical lateritic profile in the cave N4E-0022 surroundings. The results showed a satisfactory interpretation for the near-surface geoelectrical profiles and evolved to a comparison with the lateritic profile (lateritic crust, transition horizon, and saprolite horizon), providing inherent resistivity signatures for each modeled material.Keywords: applied geophysics, iron cave, Carajás.RESUMO O patrimônio espeleológico brasileiro é protegido por leis, e qualquer região com a presença de cavidades precisa de estudos científicos para auxiliar o licenciamento de empreendimentos. No contexto da mineração em terrenos ferríferos, estudos geofísicos rasos utilizando eletrorresistividade foram executados na cavidade N4E-0022, localizada no extremo norte da Mina de N4EN, Complexo Carajás. A geofísica rasa gerou imagens contínuas que potencializaram o mapeamento lito-estrutural do substrato rochoso, principalmente em locais de difícil acesso aos métodos convencionais. Os perfis de eletrorresistividade foram adquiridos com arranjo dipolo-dipolo na porção superior da cavidade. de modo paralelo entre si na porção superior da cavidade. Três seções foram executadas na direção SW-NE e duas na direção SE-NW, totalizando 435 metros de aquisição. As assinaturas geoelétricas das seções foram correlacionadas com as descrições litológicas de furos de sondagem, perfilagens geofísicas de furos de sonda e o mapeamento de detalhe do perfil laterítico no entorno da cavidade N4E-0022, evidenciando um resultado satisfatório para as interpretações realizadas. Os resultados evoluíram para uma comparação com o perfil de alteração típico de rochas ferruginosas (crosta laterítica, horizonte de transição e saprolito), e forneceram assinaturas de resistividades inerentes à cada material modelado. Palavras-chave: geofísica aplicada, caverna ferrífera, Carajás.

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Large-scale electrical resistivity tomography in the Cheb Basin (Eger Rift) at an ICDP monitoring drill site to image fluid-related structures

10.5194/se-2019-38 ◽

2019 ◽

Cited By ~ 2

Author(s):

Tobias Nickschick ◽

Christina Flechsig ◽

Jan Mrlina ◽

Frank Oppermann ◽

Felix Löbig ◽

...

Keyword(s):

Electrical Resistivity ◽

Fault Zone ◽

Large Scale ◽

Earthquake Activity ◽

Resistivity Tomography ◽

Near Surface ◽

Scientific Drilling ◽

Eger Rift ◽

Geophysical Surveys ◽

Cheb Basin

Abstract. The Cheb Basin, a region of ongoing swarm earthquake activity in the western Czech Republic, is characterized by intense carbon dioxide degassing along two known fault zones – the N-S-striking Počatky-Plesná fault zone (PPZ) and the NW-SE-striking Mariánské Lázně fault zone (MLF). The fluid pathways for the ascending CO2 of mantle origin are subject of an International Continental Scientific Drilling Program (ICDP) project in which several geophysical surveys are currently carried out to image the near-surface geologic situation, as existing boreholes are not sufficiently deep to characterize the structures. As electrical resistivity is a sensitive parameter to the presence of low-resistivity rock fractions as liquid fluids, clay minerals and also metallic components, a large-scale dipole-dipole experiment using a special type of electric resistivity tomography (ERT) was carried out in June 2017 in order to image fluid-relevant structures. We used static remote-controlled data loggers in conjunction with high-power current sources for generating sufficiently strong signals that could be detected all along the 6.5 km long profile with 100 m and 150 m dipole spacings. Extensive processing of time series and apparent resistivity data lead to a full pseudosection and allowing interpretation depths of more than 1000 m. The subsurface resistivity image reveals the deposition and transition of the overlying Neogene Vildštejn and Cypris formations, but also shows a very conductive basement of phyllites and granites that can be attributed to high salinization or rock alteration by these fluids in the tectonically stressed basement. Distinct, narrow pathways for CO2 ascent are not observed with this kind of setup which hints at wide degassing structures over several kilometers within the crust instead. We also observed gravity/GPS data along this profile in order to constrain ERT results. Gravity clearly shows the deepest part of the Cheb Basin along the profile, its limitation by MLF at NE end, but also shallower basement with an assumed basic intrusion in SW part of profile. We propose a conceptual model in which certain lithological layers act as caps for the ascending fluids, based on stratigraphic records and our results from this experiment, providing a basis for future drills in the area aimed at studying and monitoring fluids.

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Assessing a fractured landfill cover using electrical resistivity and seismic refraction techniques

Geophysics ◽

10.1190/1.1443001 ◽

1991 ◽

Vol 56 (11) ◽

pp. 1896-1904 ◽

Cited By ~ 35

Author(s):

P. J. Carpenter ◽

S. F. Calkin ◽

R. S. Kaufmann

Keyword(s):

Electrical Resistivity ◽

Seismic Refraction ◽

Seismic Energy ◽

P Wave ◽

Velocity Inversion ◽

Landfill Cover ◽

Geophysical Surveys ◽

Resistivity Variation ◽

Cover Thickness ◽

Azimuthal Resistivity

Fracturing or erosion of landfill cover materials may lead to escape of landfill gases and creation of leachate through infiltration of surface water. Periodic geophysical surveys could be used to assess landfill covers noninvasively and identify fractured or thinned areas. Models derived from electrical resistivity and seismic refraction measurements were evaluated over various portions of a closed municipal landfill in west surburban Chicago. Resistivity soundings could not delineate cover thickness over areas of fractured or new cover where resistivity contrasts with the underlying refuse were minor. Cover thickness estimates accurate to within 0.7 m, however, were obtained over unfractured mature cover where resistivities were 10–20 ohm‐m higher than in the refuse. Azimuthal resistivity variations as large as 16 ohm‐m indicate opening of cover fractures during dry weather; these same areas showed little or no azimuthal resistivity variation under moist conditions. Strong absorption of seismic energy and a velocity inversion in the refuse prevented calculation of cover thickness from seismic refraction profiles using a sledgehammer source. However, higher direct P-wave velocities (740 m/s) characterized areas of intact cover and lower velocities (370 m/s) characterized highly fractured cover. Qp for cover materials ranged from 3 to 9 and did not differ between fractured and unfractured areas.

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Neotectonic Activity in the Low-Strain Broken Foreland (Santa Bárbara System) of the North-Western Argentinean Andes (26°S)

Lithosphere ◽

10.2113/2020/8888588 ◽

2020 ◽

Vol 2020 (1) ◽

pp. 1-25

Author(s):

Ahmad Arnous ◽

Martin Zeckra ◽

Agostina Venerdini ◽

Patricia Alvarado ◽

Ramón Arrowsmith ◽

...

Keyword(s):

Electrical Resistivity ◽

Seismic Reflection ◽

Seismic Refraction ◽

Sedimentary Basins ◽

Santa Barbara ◽

Seismic Reflection Data ◽

Near Surface ◽

South Central ◽

Refraction Tomography ◽

Fault Scarps

Abstract Uplift in the broken Andean foreland of the Argentine Santa Bárbara System (SBS) is associated with the contractional reactivation of basement anisotropies, similar to those reported from the thick-skinned Cretaceous-Eocene Laramide province of North America. Fault scarps, deformed Quaternary deposits and landforms, disrupted drainage patterns, and medium-sized earthquakes within the SBS suggest that movement along these structures may be a recurring phenomenon, with yet to be defined repeat intervals and rupture lengths. In contrast to the Subandes thrust belt farther north, where eastward-migrating deformation has generated a well-defined thrust front, the SBS records spatiotemporally disparate deformation along structures that are only known to the first order. We present herein the results of geomorphic desktop analyses, structural field observations, and 2D electrical resistivity tomography and seismic-refraction tomography surveys and an interpretation of seismic reflection profiles across suspected fault scarps in the sedimentary basins adjacent to the Candelaria Range (CR) basement uplift, in the south-central part of the SBS. Our analysis in the CR piedmont areas reveals consistency between the results of near-surface electrical resistivity and seismic-refraction tomography surveys, the locations of prominent fault scarps, and structural geometries at greater depth imaged by seismic reflection data. We suggest that this deformation is driven by deep-seated blind thrusting beneath the CR and associated regional warping, while shortening involving Mesozoic and Cenozoic sedimentary strata in the adjacent basins was accommodated by layer-parallel folding and flexural-slip faults that cut through Quaternary landforms and deposits at the surface.

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The Application of Near-Surface Geophysics at Proposed Pipeline River Crossings: A Comparative Overview of Various Techniques and Their Associated Capabilities and Limitations

4th International Pipeline Conference, Parts A and B ◽

10.1115/ipc2002-27341 ◽

2002 ◽

Author(s):

Paul Tarrant ◽

David Baines

Keyword(s):

Large Diameter ◽

Seismic Refraction ◽

Directional Drilling ◽

Near Surface ◽

Design Engineers ◽

Geotechnical Investigations ◽

Geophysical Surveys ◽

Ground Conditions ◽

Borehole Drilling ◽

Near Surface Geophysics

The cost, design, and in some instances, feasibility of directional drilling large diameter or lengthy pipeline river crossings is primarily dependent on ground conditions encountered during construction. Geotechnical investigations are commonly used to explore and assess subsurface conditions at proposed crossings. Ground conditions are determined using borehole drilling and near surface geophysics. Borehole drilling provides subsurface sediment stratigraphy and depth to bedrock information. Geophysics is used to provide information between borehole locations or where borehole drilling is determined to be too difficult or too costly. When used to augment borehole results, geophysical surveys provide more complete geologic cross-section models throughout the length of a proposed directional drill path. This paper presents an overview of the more common geophysical methodologies used to profile subsurface conditions at proposed pipeline crossings. The methods discussed include ground penetrating radar (GPR), seismic refraction profiling and electrical resistivity tomography (ERT). The appropriateness and feasibility of each method is discussed in terms relating to investigation objectives of geotechnical and pipeline design engineers. All three methods were applied to two survey lines at a typical river crossing site on the Bow River, downstream from Calgary, Alberta. Results from the overlapping surveys are presented and the capabilities and limitations for each method compared. Borehole information obtained within the survey area is used to corroborate the interpreted geophysical results.

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Shallow geophysical techniques to investigate the groundwater table at the Great Pyramids of Giza, Egypt

Geoscientific Instrumentation Methods and Data Systems ◽

10.5194/gi-8-29-2019 ◽

2019 ◽

Vol 8 (1) ◽

pp. 29-43 ◽

Cited By ~ 6

Author(s):

Sharafeldin M. Sharafeldin ◽

Khalid S. Essa ◽

Mohamed A. S. Youssef ◽

Hakan Karsli ◽

Zein E. Diab ◽

...

Keyword(s):

Water Table ◽

Seismic Velocity ◽

Seismic Refraction ◽

Groundwater Table ◽

Near Surface ◽

Groundwater Aquifer ◽

Geophysical Surveys ◽

Subsurface Layers ◽

Average Water ◽

Ground Penetrating

Abstract. The near-surface groundwater aquifer that threatened the Great Pyramids of Giza, Egypt, was investigated using integrated geophysical surveys. A total of 10 electrical resistivity imaging, 26 shallow seismic refraction, and 19 ground-penetrating radar surveys were conducted in the Giza Plateau. Collected data for each method were evaluated by state-of-the art processing and modeling techniques. A three-layer model depicts the subsurface layers and better delineates the groundwater aquifer and water table elevation. The resistivity of the aquifer layer and seismic velocity vary between 40 and 80 Ωm and between 1500 and 2500 m s−1, respectively. The average water table elevation is about +15 m, which is safe for the Great Sphinx, but it is still subjected to potential hazards from the Nazlet El-Samman suburb where the water table elevation reaches 17 m. A shallower water table at the Valley Temple and the tomb of Queen Khentkawes, with a low topographic relief, represents severe hazards. It can be concluded that a perched groundwater table is detected in the elevated topography to the west and southwest that might be due to runoff and capillary seepage.

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