Physical Sciences and Mathematics Commons^™

Applied Geochemistry, Geochronology And Biostratigraphy: Case Studies From The 38th Parallel Structures In Missouri And Orange Basin, Offshore Western South Africa, Marissa Kay Spencer

Doctoral Dissertations

"The unique alignment of the Decaturville, Crooked Creek, and Weaubleau geological structures in central Missouri, three of nine known such structures along the 38th parallel in Illinois, Missouri, and Kansas, has puzzled geoscientists for decades. Research using palynology (palynomorphs and particulate organic matter) and radiometric dating of impact spherules were used to constrain age and a relationship between these enigmatic structures and infer their paleoenvironmental conditions. Novel melting damages, unique to impact, were documented in the palynomorphs in all the three structures. Early Ordovician acritarchs with melted processes correlate with ⁴⁰Ar-³⁹Ar stepwise heating age of impact spherules …

Mantle Flow And Transition Zone Discontinuities Beneath The Carribean Plate: Constraints From Shear Wave Splitting And Receiver Function Analyses, Tu Xue

Doctoral Dissertations

"Azimuthal anisotropy quantified by teleseismic SKS, SKKS, PKS (“XKS”) and local S wave splitting parameters is used to investigate lithospheric deformation and asthenospheric flow beneath the boundary zone of the North American and Caribbean plates and adjacent areas. A total of 4915 XKS and 1202 pairs of local S wave splitting parameters were obtained at 24 broad band seismic stations. The XKS observations can be divided into two groups based on the spatial distribution of the resulting fast polarization orientations. Those observed on the Caribbean Plate are mostly WNW-ESE which are roughly trench-parallel. In contrast, the fast orientations observed on …

Application Of Machine Learning In Geophysics: Ranking Teleseismic Shear Wave Splitting Measurements And Classifying Different Types Of Earthquakes, Yanwei Zhang

Doctoral Dissertations

"During the past decades, applications of Machine Learning have been explosively developed to solve various academic and industrial problems, and over-human performance has been shown in diverse areas. In geophysical research, Machine Learning, especially Convolutional Neural Network (CNN), has been applied in numerous studies and demonstrated considerable potential. In this study, we applied CNN to solve two geophysical problems, ranking teleseismic shear splitting (SWS) measurements and classifying different types of earthquakes.

For ranking teleseismic SWS measurements, we utilized a CNN-based method to automatically select reliable SWS measurements. The CNN was trained by human-verified teleseismic SWS measurements and tested using synthetic …

Depositional Conditions, Stratigraphic Evolution, And Allo- And Autogenic Controls Of Lower Permian Non-Marine Carbonate Rocks, Lucaogou Low-Order Cycle, Bogda Mountains, Nw China, Yiran Lu

Doctoral Dissertations

"The overall objective of this study is to interpret the depositional conditions of lacustrine carbonate deposits of the lower Permian Lucaogou low-order cycle in the greater Turpan-Junggar continental rift basin, NW China. The depositional environments of ten carbonate lithofacies in the Tarlong-Taodonggou half graben and the Zhaobishan section were interpreted. Allo- and autogenic factors were identified. They controlled characteristics and distribution pattern of carbonate deposits in regional and local scale, respectively. Allogenic factors include the amount and direction of regional siliciclastic input, basin geometry, cyclic humidity/aridity oscillation, temperature, and regional tectonics. Autogenic factors include local siliciclastic input, local topography, local …

Laterally Heterogeneous Seismic Anisotropy Investigated By Shear Wave Splitting Analyses, Yan Jia

Doctoral Dissertations

"Numerous geophysical studies suggest that seismic anisotropy is a nearly ubiquitous property of the Earth’s crust and upper mantle. In this study, we utilize the shear wave splitting technique to investigate the piercing-point-dependent azimuthal anisotropy beneath the northeastern edge of the Sichuan Basin in central China, and the spatial and temporal variations of anisotropy near the 2019 M7.1 Ridgecrest earthquake in California, respectively. A clear back azimuthal dependence of the splitting parameters and the lack of a 90° or 180° periodicity of azimuthal variation in the observed fast orientations provide strong evidence for the existence of piercing-point-dependent anisotropy beneath the …

Adsorption Of Arsenic Onto River Sediments, Leticia Augusta Dos Santos Ferreira

Masters Theses

“Previous studies have noted the relationship between shallow groundwater rich in sodium (Na) and bicarbonate (HCO₃) and elevated levels of dissolved arsenic. However, most experimental work on arsenic adsorption in the presence of HCO₃ and differing Na/Ca ratios has proven difficult to extrapolate to natural systems because of differences in tested mineral compositions and component concentrations. In this study, I performed a series of adsorption experiments using river sediments to evaluate the influence of HCO₃ and monovalent/divalent cations on the extent of arsenic adsorption onto natural sediment in groundwater.

Batch adsorption (kinetics, equilibrium, and metal loading) …

Crustal And Upper Mantle Structure Beneath The Southeastern United States From Joint Inversion Of Rayleigh Wave Dispersion And Receiver Functions, Qiuyue Yang

Doctoral Dissertations

"In spite of numerous geophysical investigations have been conducted in southeastern United States, the structure and evolution of the crust and lithospheric mantle remain controversial due the thick sedimentary covers atop the crust of the coastal plains there. In this study, we use data from 186 broadband seismic stations belonging to the USArray Transportable Array to construct a 3-D shear wave velocity model for the southeastern United States for the top 180 km by a joint inversion of Rayleigh wave phase velocity dispersion and receiver functions. Our results show a clear spatial correspondence with major surficial geological features. A prominent …

Spatiotemporal Variations Of Upper Crustal Anisotropy Along The San Jacinto Fault Zone In Southern California And The Fairview Region In Central Oklahoma, Enyuan Jiang

Doctoral Dissertations

"To discern spatial and explore the possible existence of temporal variations of upper crustal anisotropy along an ~15 km section of the San Jacinto Fault Zone (SJFZ) in California, and in the Fairview, Oklahoma, region, we conduct systematic shear wave splitting (SWS) investigations using local S-wave data recorded by seismic stations. Strong spatial variations in crustal anisotropy are revealed by 1694 and 405 pairs of splitting parameters (including the fast polarization orientation and the splitting time), respectively. For both areas, for raypaths traveling through the fault zones, the fast orientations are parallel to the faults and may be attributed to …

Receiver Function Imaging Of The 410 And 660 Km Discontinuities And Seismic Azimuthal Anisotropy Revealed By Shear Wave Splitting Beneath The Australian Continent, Kailun Ba

Doctoral Dissertations

"The Australian continent is composed the of Precambrian cratons in the west and Phanerozolc orogens in the east. Despite numerous seismological studies, controversies remain regarding the structure, evolution, and dynamics of the crust and mantle beneath Australia. In this study, we used two techniques, receiver functions and shear wave splitting analyses, to investigate the topography of the mantle transition zone (MTZ) discontinuities and mantle seismic azimuthal anisotropy, respectively. We utilized P-to-S receiver functions to map the 410 and 660 km discontinuities bordering the MTZ. The discontinuity depths obtained show a systematic apparent uplifting for both discontinuities in central and western …

Spatial Variations Of Teleseismic P-Wave Attenuation And Scattering Beneath The Southeastern United States And The Malawi And Luangwa Rift Zones In East Africa, Ashutosh Shrivastava

Doctoral Dissertations

"Seismic attenuation is an important physical parameter for characterizing subsurface morphology and the thermal structure of the Earth’s crust and mantle. In this study, teleseismic P-wave amplitude spectra are used to examine the seismic attenuation beneath the southeastern United States and the Malawi and Luangwa rift zones in east African. The resulting seismic attenuation parameters (Δt*) reveal a systematic contrast between the Appalachian Mountains and the Gulf of Mexico Coastal Plain exhibiting high and low attenuation, respectively. Spatial coherency analysis of the Δt* observations suggests that the center of the low-attenuation layer is located within the uppermost mantle at about …

Mantle Flow Systems Associated With Slab Subduction And Absolute Plate Motion In Alaska Constrained By Shear Wave Splitting Analyses, Yuchen Yang

Doctoral Dissertations

"Alaska has long been recognized as a geologically complex region with a sharp contrast in tectonic activity between southern and northern Alaska. While the former is characterized by the subduction of the geometrically varying Pacific-Yakutat plate beneath the North American plate, the latter has a mostly stable cratonic setting. To investigate the mantle flow fields beneath Alaska and understand the influence of the subduction process on regional mantle dynamics, a total of 2790 pairs of well-defined teleseismic shear wave splitting (SWS) measurements recorded from 379 stations are obtained and analyzed. In addition, 247 pairs of SWS results from local earthquake …

Strain Partitioning Across The Polochic-Motagua Fault System In Guatemala: Insight From Kinematic Modeling, Qiaoqi Sun

Masters Theses

”The Polochic-Motagua Fault System in Guatemala is the on-land segment of the sinistral transform plate boundary between the North American Plate and the Caribbean Plate. Three major seismically active strike-slip faults in this fault system pose significant earthquake threats to surrounding populated cities. The assessment of seismic hazard requires a better understanding of the kinematics of the fault system. GPS monitoring indicates that seventy-five percent of the ~20 mm/yr. plate motion is accommodated by the Motagua Fault and less than twenty-five percent is accommodated by the Polochic Fault. However, the Polochic Fault documents a lateral offset of ~132 ± 5 …

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 …

A Broad Iceland Plume Associated With Two Phase Transitions At The 660 Km Discontinuity: Constraints From Receiver Functions, Dan Wang

Doctoral Dissertations

"In spite of the fact that Iceland is frequently regarded as the archetypal example of mantle plumes, the existence, depth extent, origin, dimension and excess temperature of the hypothesized plume remain enigmatic and hotly debated. The controversy mostly originates from the limited vertical resolution of seismic tomography techniques and the associated uncertainty in the depth and lateral extents of the lower wavespeed anomaly. Here we utilize a robust receiver-function-based technique to image the topography of the 410 and 660 km discontinuities bordering the mantle transition zone beneath Iceland and surrounding oceanic regions, and construct thermal and seismic wavespeed models of …

Seismological Investigations Of Lithospheric Structure Beneath The East African Rift System And The Kalahari Craton, Tuo Wang

Doctoral Dissertations

"In spite of numerous geophysical studies have been conducted in East African Rift System and Southern Africa, the structure and evolution of the crust and upper mantle are still controversial. In this study, we applied multiple seismological techniques to investigate the structure in the crust and uppermost mantle beneath the East African Rift System and Kalahari Craton in southern Africa. First, the technique of ambient noise tomography was applied to image shear wave velocity model from surface to the depth of 40 km beneath the Malawi and Luangwa rift zones. For the first time, a high-resolution 3-D shear wave velocity …

Determining Variable Depth To Bedrock Using Ert And Masw: A Geophysical Investigation In St. Louis, Mo, Justin James Clinton

Masters Theses

“The research involves a geophysical study in the Maremec River Valley in St. Louis County, Missouri. The geophysical methods described in this paper can provide a relatively quick, inexpensive, and accurate means in investigating the lithologic characteristics of the subsurface. Method selection is ultimately dependent of the type of investigation and site-specific characteristics. In this investigation, Electrical Resistivity Tomography (ERT) data and Mutli-Channel Analysis of Surface Waves (MASW) data were acquired to image the bedrock beneath the Maremec River to an approximate depth of 110 ft or an elevation of 300 ft for a proposed wastewater tunnel. Two overlapping dipole-dipole …

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 …

Seismic Attribute Assisted Depositional Facies Identification And Stratigraphic Correlation In The Central Gulf Coast Region Of Texas, Yani Lin

Doctoral Dissertations

"The sandstone deposits in the fluvial-dominated delta systems in the Lower Wilcox Group above the Cretaceous carbonate shelf edges of the Texas Gulf Coast Region are considered as high exploration potential reservoir bodies. However, the multi-phase regression and transgression during the late Paleocene to the early Eocene complicate the local depositional structure. The depositional facies is hard to be identified in details using the traditional seismic stratigraphic interpretation method. Seismic attributes are effective in detecting depositional facies, especially in mapping channels and investigating reservoir characteristics. In this study, we utilize seismic attributes to identify the principal depositional facies in the …

Amplitude-Preserved Processing Of The Blackfoot 10 Hz Seismic Data, Bader Mohammed A Algarni

Masters Theses

"The broadband 3C-2D seismic survey was acquired in the Blackfoot Field in southern Alberta. The single-component 10 Hz geophone data were reprocessed to increase vertical resolution and provide a better seismic image of the incised valley channel fill deposits in the Glauconitic Formation. The amplitude-preserved seismic processing of the data was followed by the Kirchhoff prestack time migration. The processing parameters and algorithms used were based on parameter optimization approach. Elevation statics and surface consistent residual statics were utilized to remove near surface delays in the data. Seismic noise, such as ground roll and air blast, were attenuated effectively by …

Archaeological Investigation Using Geophysical Methods To Locate Historic Byram's Ford Road, Marshall Seth Foster

Masters Theses

"Ground penetrating radar, a time domain electromagnetic metal detector and a frequency domain electromagnetic metal detector were used with the goal of locating a section of the Byram's Ford Road believed to be intersecting the historic Big Blue Battlefield in the Westport area of Kansas City, Missouri.

Ground penetrating data were acquired at three sites, Site A, Site B, and Site C. The time domain EM metal detector was used to acquire data at Site A, where subsequent ground truthing was conducted using the frequency domain EM metal detector and an excavation tool. Significant anomalies were visible on both the …

Reprocessing And Comparison Of The 2 Hz And 10 Hz Vertical Component Seismic Data Of The Blackfoot 3c-2d Survey, Mete Sarikaya

Masters Theses

"The Blackfoot seismic 3C-2D data were obtained from the Consortium for Research in Elastic Wave Exploration Seismology (CREWES) Project in 1995. The seismic data acquisition was performed in the Blackfoot Field, which is around 15 km southeast of Strathmore, Alberta. The 4 Hz and 10 Hz vertical component data are reprocessed to increase the quality and resolution of the seismic images. The Glauconitic sand reservoir at approximately 1.1 s, and a strong reflection about at 1.5 s are the focuses of the study.

The processing procedure includes different parameters and methods to obtain the best seismic sections of 2 Hz …

Geophysical Imaging Beneath Lake Chesterfield, Missouri, James Daniell Hayes

Masters Theses

"Lake Chesterfield in Wildwood, Missouri, has been leaking since construction of the earth-fill dam was completed in 1986, despite numerous mitigation efforts. The mitigation efforts, including the injection of grouting and the emplacement of clay liners, has not solve the leakage problem.

In the current study, geophysical (subsurface imaging) data was acquired across the drained and dry lake bed and along the base of the earth-fill dam to 1) map variable depth to top of bedrock, 2) determine the variable quality of the bedrock to depths on the order of 80 ft., 3) identify any significant karst features beneath the …

U-Pb Detrital Zircon Geochronology Of Paleozoic Clastics Of The Ozark Plateau: Implication For Sea-Level Fluctuations And Far-Field Tectonics, Chen Zhao

Masters Theses

"The Ozark Plateau of south-central Missouri is underlain by Ordovician to Pennsylvanian carbonate and clastic strata. Enigmatic, presumably Pennsylvanian 'filled sink' structures are common on the Ozark Plateau and remain a source of controversy. We present results for U-Pb ages of detrital zircons for 13 samples from the OP. We use U-Pb ages from other Paleozoic clastics and 'filled sinks' on the OP, to suggest: 1) FSS record a period of Middle Ordovician erosion and sedimentation and 2) document significant shifts in sediment provenance that reflect regional tectonic events affecting the North American Craton.

The KDE plots of normalized detrital …

Receiver Function Investigations Of Mantle Transition Zone And Crustal Structure In East Africa And Northeast Asia, Muchen Sun

Doctoral Dissertations

"In spite of numerous geophysical studies have been conducted in East Africa and Northeast Asia, the structure and evolution of the crust, upper mantle, and the mantle transition zone (MTZ) are still controversial. The MTZ discontinuities beneath the study area are imaged by stacking an unprecedented volume of receiver functions (RFs). The normal MTZ thickness beneath the Western Branch of the EARS and Tanzania Craton indicates the absence of present-day thermal upwelling from the lower mantle. In contrast, beneath the Eastern Branch, a significant MTZ thinning reveals the existence of thermal upwelling from either the upper MTZ or the lower …

Fault Imaging Enhancement In Taranaki Basin, New Zealand And Rock Physics And Inversion Based Reservoir Characterization In The Central Gulf Coast Region Of Texas, Tianze Zhang

Doctoral Dissertations

"Fault imaging technique and reservoir characterization based on rock physics analysis and pre-stack inversion has been widely used hydrocarbon exploration. For the fault imaging technique, the ant tracking has been widely used in fault interpretation. However, the reliability of the results is highly dependent on appropriately choosing a signal processing method and volume attributes. In our study area, which lies in the southern Taranaki Basin, we applied Graphic Equalizer as the processing tool and the Chaos attribute before running the ant tracking algorithm. Results show that the procedure provides a better result and can map both the major and minor …

Seismic Anisotropy And The Mantle Dynamics Beneath The Arabian Plate, Saleh Ismail Hassan Qaysi

Doctoral Dissertations

"We investigate mantle seismic azimuthal anisotropy and deformation beneath the Arabian Plate and adjacent areas using data from 182 broadband seismic stations which include 157 stations managed by the Saudi Geological Survey. A total of about 4000 pairs of shear wave splitting parameters are obtained using the transverse minimization technique. The individual XKS (including PKS, SKS, and SKKS) splitting measurements were manually checked to ensure the quality. The well-defined parameters show dominantly N-S fast orientations at the majority of the stations, and NW-SE fast orientations along the Zagras Mountain front. No clear systematic variations of the splitting parameters as a …

Reprocessing Of The 2 Hz P-P Data From The Blackfoot 3c-2d Survey With Special Reference To Multicomponent Seismic Processing, Onur Akturk

Masters Theses

"The 3C-2D multicomponent seismic survey was acquired in the Blackfoot Field, which is located 15 km southeast of Strathmore, Alberta. The 2 Hz vertical component data were reprocessed to better image the target reservoir, the Glauconitic sand formation at approximately 1150 ms. The zone of the major reflector at about 1550 ms was also taken into consideration to determine the better seismic section for further processing. The main characteristics of the converted wave processing, such as common conversion point (CCP), asymptotic binning, gamma ratios, receiver statics, rotation of the data, positive/negative offsets, and anisotropy, were also summarized in this study. …

Salt Mobility Under Different Geological Regimes, Oznur Surek

Masters Theses

"This study investigates the evolution of Dan Salt Structure in the southern salt dome province, Danish Central Graben and Mars-Ursa Basin in the Northern Gulf of Mexico to understand salt and sediment interaction over time under different geologic regimes. An integration of structural and stratigraphic analyses is conducted to understand the relationship between halokinesis and sedimentation.

Interpretation of the seismic data in Dan Salt Structure shows that the structure has a complex geometry, which is divided into upper and lower parts. The evolutionary stage of both the upper and lower parts of the structure has been influenced by salt. The …

3d Seismic Imaging Of Submarine Stratovolcanic And Salt Structures Beneath The Taranaki Basin, New Zealand And The Gulf Of Mexico, Ersin Erdem Unkaracalar

Masters Theses

"The relationship of submarine stratovolcanic and salt structures with overlying sediments creates a significant role in the petroleum system due to the emplacement and burial of volcano and salt. This study characterizes the spatial and temporal distribution of structural and stratigraphic features associated with submarine stratovolcano and salt body to provide insights for elements and processes of petroleum geology related to regional tectonics.

The stratovolcanic and salt structures are clearly identified on seismic sections. However, distortion of ray paths passing through the salt and turning seismic waves prevents accurate identification of steep flanks of salt. The seismic response to a …

Bridge Deck Assessment Using Visual Inspection, Ground Penetrating Radar, Portable Seismic Property Analyzer-Ultrasonic Surface Wave, Hammer Sounding And Chain Drag, Abdullah Hadi Zaid Alhaj

Masters Theses

"Integrated non-destructive techniques were utilized to assess the condition of a reinforced concrete bridge deck. There were two main objectives accomplished.

The first objective was to assess the integrity of the reinforced concrete bridge deck using four non-destructive techniques, namely visual inspection, ground penetrating radar, portable seismic property analyzer-ultrasonic surface wave, and hammer sounding and chain drag. Visual inspection data were used to identify signs of deterioration on surface of the bridge deck such as cracking, concrete leaching, and reinforcement corrosion. Ground penetrating radar data were used to determine the relative condition of the bridge deck. However, due to the …