Geophysics and Seismology Commons^™

Geophysical Characteristics Of Nickel And Copper Deposits In Wadi Al Khadra Prospect, Southwestern Of Saudi Arabia, Abdulrahman Ahmed Aljabbab

Doctoral Dissertations

“Three geophysical datasets (self-potential, magnetics, and time - domain electromagnetics) were acquired at Wadi Al Khadra Ni-Cu prospect in southwest Saudi Arabia, and were processed and interpreted for the Saudi Geological Survey. The primary objectives were to map the distribution of metallic mineralization, map structures, verify the integration of the geophysical interpretations and its signatures in conjunction with boreholes information, distinguish the similarities and differences in the integrated interpretation of geophysical data, and design optimal processing and interpretation data parameters. The self-potential tool was used to map the variation in natural surface potential differences to map lateral variations in the …

Geophysical Assessment Of The Lake Chesterfield Site, Missouri, Diya Ali Ahmad Alfuqara

Doctoral Dissertations

"Since construction of the Lake Chesterfield, Missouri in 1986, significant leaks have occurred causing the lake to lose substantive volumes of water. Mitigation efforts, have not solved the problem. Indeed, in June of 2017, the water level in Lake Chesterfield dropped at an alarmingly rapid rate. Prior to authorizing additional mitigation work, the Lake Chesterfield. Home Owners Association (LCHOA) decided to acquire geophysical data across the drained and dry lake bed. These information would help a geotechnical engineering firm determine the most appropriate mitigation plan.

In the summer of 2018, electrical resistivity tomography, multichannel analysis of surface wave, and spontaneous-potential …

Delineation Of A Coal Combustion Residue Landfill And Underlying Karst Subsurface In Southwest Missouri Using Ert And Masw Surveys, Ruobai Zhao

Doctoral Dissertations

"The safe containment of coal combustion residual (CCR) in landfills was addressed by the U.S. Environment Protection Agency (EPA) CCR rule published in 2015. The new rule affects new and existing U.S. based CCR landfills in terms of implementing safeguard systems for safe disposal and contamination control. Electrical resistivity tomography (ERT) and multichannel analysis of surface waves (MASW) data were acquired across and in proximity to a CCR landfill in southwest Missouri, USA, with the intent to identify potential karst features and seepage pathways.

Electrical resistivity tomography data were acquired using an automated 8-channel resistivity meter and multichannel analysis of …

The Utility Of Geophysical Techniques To Image The Shallow Subsurface In Karst Areas In Missouri, Nathainail Bashir

Doctoral Dissertations

"This dissertation is composed of three papers, which are focused on the utility of geophysical techniques to imaging the shallow subsurface in karst areas in Missouri.

In the first paper, ground penetrating radar (GPR) and time domain electromagnetic metal detector (TDEM-MD) methods were effectively deployed in an investigation of the cemetery with the intent of locating unmarked graves. The outcome of this study is to expand the knowledge of GPR and TDEM-MD methods, to locate unmarked graves in cemeteries. The study concluded that the GPR method is superior than TDEM-MD to locate buried caskets in cemetery investigations.

In the second …

In-Situ Assessment Of Concrete Bridge Decks And Pavements Using Stress-Wave Based Methods, Mengxing Li

Doctoral Dissertations

"Concrete infrastructure of United States is aging and deteriorating. Accurate assessment the condition of concrete infrastructure is critical for its maintenance and rehabilitation. Stress-wave based methods, including ultrasonic surface wave (USW) and impact echo (IE), are becoming popular for characterizing defects and mechanical properties of concrete infrastructures. In this dissertation, a comprehensive literature review of seismic wave theory and common types of defects identified in concrete infrastructures, as well as stress-wave based methods used for concrete infrastructure monitoring and characterizing on a selected concrete bridge deck and two concrete pavement segments are present. The utility and reliability of both methods …

The Use Of Geophysical Methods For Dam Seepage Investigations And Dredged Oyster Deposit Characterization, Stanley Chinedu Nwokebuihe

Doctoral Dissertations

"The dissertation is made up of three papers, which discuss the utility of geophysical tools in earthfill dam investigations and dredged oyster bed characterization.

In the first paper, an earthfill dam in Warren County, Missouri was effectively investigated for seepage through the dam and its outlet works using an integration of the electrical resistivity tomography, induced polarization and spontaneous potential geophysical tools. Recommendations were subsequently made based on the results of the study on grout locations to prevent further seepage. In the second paper, a similar study of earthfill dam seepage was conducted on a different dam in Southern Missouri. …

Dissolution-Enlarged Fractures Imaging Using Electrical Resistivity Tomography (Ert), Elnaz Siami-Irdemoosa

Doctoral Dissertations

"In recent years the electrical imaging techniques have been largely applied to geotechnical and environmental investigations. These techniques have proven to be the best geophysical methods for site investigations in karst terrain, particularly when the overburden soil is clay-dominated. Karst is terrain with a special landscape and distinctive hydrological system developed by dissolution of rocks, particularly carbonate rocks such as limestone and dolomite, made by enlarging fractures into underground conduits that can enlarge into caverns, and in some cases collapse to form sinkholes.

Bedding planes, joints, and faults are the principal structural guides for underground flow and dissolution in almost …

Acquisition Of Active Multichannel Analysis Of Surface Waves (Masw) Data In Karst Terrain, Ghassan Salem Alsulaimani

Doctoral Dissertations

"This study was designed to verify the effects and data reproducibility when the length of receiver array, receiver spacing, source offset and array orientation parameters are changed for data acquired using multichannel analysis of surface waves (MASW), at intended target depth of 30ft (9m), and to compare the results with electrical resistivity tomography (ERT) data obtained for the same study site.

The MASW data acquired for 34 sites, along four profiles for each site using variable source offsets of 10ft (3m) and 30ft (9.1m), and variable receiver spacings of 2.5ft (0.76m) and 5.0ft (0.76m), concurrently. Out of the 272 profiles …

Integrated Geophysical Approach Using Electrical Resistivity Tomography And Multichannel Analysis Of Surface Wave In Assessing Wilson Spring Development, Ibrahim E. Ahmed

Doctoral Dissertations

"This research investigated fractured zones leading to preferential flow paths of Wilson Spring. In this context, electrical resistivity tomography (ERT) data and multi-channel analyses of surface waves (MASW) data were acquired at studied site with the purpose of mapping a variable depth to top of bedrock and geological structures.

Interpretation of the boreholes, MASW, and ERT data indicated that a depth to top of rock does vary significantly at the studied site due to many solution-widened fractures. Multiple near-vertical solution-widened fractures were mapped in the studied site based on the interpretation of the ERT data. The mapped solution-widened fractures appear …

Identifying Shallow Subsurface Stratigraphy And Voids Using Dispersive Characteristics Of Electromagnetic And Surface Waves, Payman Hajiani

Doctoral Dissertations

"This dissertation presents the results of three manuscripts on spectral analysis of electromagnetic and seismic surface waves to detect subsurface stratigraphy and voids. In the first manuscript, a new technique was developed by utilizing spectral analysis of surface waves to detect subsurface openings. This technique applied the concept of group delay to evaluate the effects of subsurface voids on the phase shift domain. Seismic data sets were acquired at different sites where the shape, size, and depth of the void varied. In all surveys, the time delay technique precisely identified the locations of the subsurface openings. The second manuscript presents …

Assessment Of Highway Condition Using Combined Geophysical Surveys, Abdallah Alhadi Dera

Doctoral Dissertations

"Four pavement sections were investigated using ground penetrating radar (GPR) and Ultrasonic Surface Wave (USW). The objective of this research was to compare the effectiveness of two non-destructive geophysical tools, GPR and the PSPA, in assessing the condition of the pavements, composed of different construction materials. The GPR data were acquired using a 1.5 GHz antenna along five traverses spaced at two ft. intervals approximately 1000 ft. long. On the other hand, the PSPA data were acquired at the stations spaced at 1000 ft. along the five GPR traverses. Core samples were collected at each site to constrain the interpretation …

Geophysical Imaging Of Karst Features In Missouri, Jeremiah Chukwunonso Obi

Doctoral Dissertations

"Automated electrical resistivity tomography (ERT) supported with multichannel analysis of surface waves (MASW) and boring data were used to map karst related features in Missouri in order to understand karst processes better in Missouri. Previous works on karst in Missouri were mostly surficial mapping of bedrock outcrops and joints, which are not enough to define the internal structure of karst system, since most critical processes in karst occur underground. To understand these processes better, the density, placement and pattern of karst related features like solution-widened joints and voids, as well as top of bedrock were mapped. In the course of …