Physical Sciences and Mathematics Commons^™

Machine Learning Model Selection For Predicting Global Bathymetry, Nicholas P. Moran

University of New Orleans Theses and Dissertations

This work is concerned with the viability of Machine Learning (ML) in training models for predicting global bathymetry, and whether there is a best fit model for predicting that bathymetry. The desired result is an investigation of the ability for ML to be used in future prediction models and to experiment with multiple trained models to determine an optimum selection. Ocean features were aggregated from a set of external studies and placed into two minute spatial grids representing the earth's oceans. A set of regression models, classification models, and a novel classification model were then fit to this data and …

Seismic Loading Effects Within Orthogonally Connected Steel Lateral Force Resisting Systems, Alhussin Faraj Aliwan

Graduate Theses and Dissertations

Steel buildings located within seismically active regions require special design considerations to ensure public safety and prevent collapse during an extreme seismic event. Two commonly used steel systems are special moment frames (SMFs) and buckling-restrained braced frames (BRBFs). When two seismic systems share a common column in an orthogonal configuration (such as at a building corner), design specifications currently consider a 100+30 rule wherein the shared column is designed for 100% fuse demand in one direction, plus 30% fuse demand from the other direction. While this rule has been shown to be reasonable for elastic building response, a few studies …

Evaluating Hydration And Artificial Aging Effects On The Paleointensity In Natural Glass, Sebastian Fearn

Theses and Dissertations

Young natural volcanic glasses have been successfully used to recover Earth’s geomagnetic field intensity (paleointensity). However, the magnetic stability and reliability of volcanic glass as a paleomagnetic recorder over geologic time is unclear. Paleointensity estimates may be influenced by natural processes that alter magnetic mineralogy. Previous results from paleointensity and rock magnetic experiments suggest that post-emplacement hydrothermal alteration can alter the magnetic remanence and can possibly cause paleointensity experiments to fail. Low-temperature hydration and natural relaxation of the glass structure over time may also adversely impact paleointensity results. In this study, rhyolitic and basaltic glass specimens underwent artificial aging and …

Paleotectonic Investigation By Successive 3d Seismic Horizon Flattening In The Pennsylvanian Interval Of Western Osage County, Oklahoma, Douglas Cooper Mccabe

Graduate Theses and Dissertations

3D seismic and well log data in Western Osage County, Oklahoma, are utilized to evaluate possible intracratonic tectonic signals present in the subsurface stratigraphy of the Cherokee Platform as a result of the regional tectonic events of Pennsylvanian age. These events include: the Wichita, Ouachita, and Arbuckle orogenies, the Nemaha and Ozark Uplifts, and the Southeast Oklahoma Aulacogen. Horizon flattening within 3D seismic volumes allows for identification of paleotectonic structures and syntectonic depositional features, which may be related to the collateral effects of these orogenies on the Cherokee Platform. Identified structures were assigned geologic ages using precision synthetic seismograms tuned …

Seismic Expressions Of Paleokarst, Olanrewaju Ayodapo Aboaba

Graduate Theses and Dissertations

Paleokarst are characterized by epigene and/or hypogene processes in their formation and hold significant numbers of hydrocarbons and other natural resources. This dissertation examines worldwide seismic expression of paleokarst; and specifically, the characterization of paleokarst reservoirs developed across the Cherokee Platform, and in the Arkoma Basin, Oklahoma.

Worldwide subsurface paleokarst formations are of Precambrian to Miocene age and found at depths less than 200 m to as great as 8000 m. Karst can be are expressed on seismic records as sinkholes, paleocave collapse, and tower morphologies. Seismic modeling indicates that karst can be modeled and imaged to better understand its …

Initial Measurements On The Effect Of Stress On P- And S-Wave Velocities In Olivine, Taryn Traylor

UNLV Theses, Dissertations, Professional Papers, and Capstones

It is well known that elasticity is a key physical property in the determination of the structure and composition of the Earth and provides critical information for the interpretation of seismic data. This study investigates the stress-induced variation in elastic wave velocities, known as the acoustoelastic effect, in San Carlos olivine. A recently developed experimental ultrasonic acoustic system, the Directly Integrated Acoustic System Combined with Pressure Experiments (DIASCoPE), was used with the D-DIA multi-anvil apparatus to transmit ultrasonic sound waves and collect the reflections. We use the DIASCoPE to obtain longitudinal (P) and shear (S) elastic wave velocities from the …

A Periglacial Landsystem Analysis In The Canadian High Arctic: A Tool For Planetary Geomorphology, Chimira Nicole Andres

Electronic Thesis and Dissertation Repository

Permafrost underlies 50% of Canada’s terrain and underlies 24% of the Earth’s total land area. It is a major driving force in the generation and evolution of patterned ground landforms such as polygons, stone circles, mud boils, and stripes, etc. that are seen on both the surface of the Earth and Mars, specifically in periglacial domains. The distribution of subsurface ice in these landforms (i.e. polygonal terrain) on Earth is a key constraint on past climate and process-form relationships in high arctic and periglacial regions. These landforms also have the potential of storing ice in the subsurface meaning that the …

Forecasting The Development Of A Natural Levee Breach And Subsequent Sediment Distribution At Mardi Gras Pass, Louisiana, Joshua Hansen

University of New Orleans Theses and Dissertations

In 2012, a breach in a natural levee occurred on the Mississippi River near the Bohemian Spillway, forming a new distributary named Mardi Gras Pass. Since its genesis, scientists from local universities and NGOs have been regularly performing bathymetric and bank surveys to track the channel’s expansion, as well as discharge surveys throughout the receiving basin. This study developed and implemented a hindcast simulation based on this wealth of data utilizing the morpho- and hydrodynamic model, Delft3D. This model was then used to create a 20-year forecast and a 1-year simulation without tidal and subtidal forces. The results demonstrated that …

A Gis-Based Method For Archival And Visualization Of Microstructural Data From Drill Core Samples., Elliott Holmes

Electronic Theses and Dissertations

Core samples obtained from scientific drilling could provide large volumes of direct microstructural and compositional data, but generating results via the traditional treatment of such data is often time-consuming and inefficient. Unifying microstructural data within a spatially referenced Geographic Information System (GIS) environment provides an opportunity to readily locate, visualize, correlate, and explore the available microstructural data. Using 26 core billet samples from the San Andreas Fault Observatory at Depth (SAFOD), this study developed procedures for: 1. A GIS-based approach for spatially referenced visualization and storage of microstructural data from drill core billet samples; and 2. Producing 3D models of …

Experimental Polycrystal Stress Mapping Using Raman Spectroscopy, Genevieve C. Kidman

UNLV Theses, Dissertations, Professional Papers, and Capstones

Stress conditions leading to rock deformation influence how a rock will ultimately deform. However, the internal distribution of stress in an elastically anisotropic rock under load, a precursor to rock deformation, is not well understood. Two models that may describe the distribution of stress in polycrystals include the Reuss bound and stress percolation. The Reuss bound, when applied to a polycrystal, describes isostress on each grain resulting in homogeneous intragranular strain and heterogeneous intergranular strain. The stress percolation model involves a network of strong contacts or force chains containing domains of high stress interwoven through areas of lower stress that …

Quaternary Shelf-Slope Development In The Northern Gulf Of Alaska From Combined Geophysical And Geomorphologic Analysis, Wesley A. Clary

Earth and Planetary Sciences ETDs

This dissertation follows the hybrid format as defined by the Office of Graduate Studies at the University of New Mexico. The three chapters defined herein were prepared as manuscripts to be submitted for publication in peer reviewed journals in the field of Earth sciences. A version of chapter 1 was published in Proceedings of the Integrated Ocean Drilling Program, 2017, Volume 41. Chapter 2 was submitted to Marine Geology in Feb 2020, and is under revision as of this date. A version of chapter 3 will be submitted to the Journal of Geophysical Research. In chapter 1, I …

3-D Shear Wave Velocity Structures Of The Crust And Upper Mantle Beneath Cascadia And New Zealand From Full-Wave Ambient Noise Tomography, Sampath Rathnayaka Mudiyanselage

Doctoral Dissertations

The (de)hydration process and the amount of hydrated sediment carried by the downgoing oceanic plate play a key role in the subduction dynamics. The deformation and (de)hydration of the downgoing tectonic plates, as well as the seismic, tsunami, volcanic hazards, in Cascadia and the New Zealand regions are not fully understood, partly due to a lack of combined studies of onshore and offshore data. In order to address these questions, we developed a 3-D high-resolution shear wave velocity model beneath Cascadia, the North and the South Islands of New Zealand, extending from offshore to onshore, with the use of full-wave …

Geospatial Analyses Of Seismic Hazards And Risk Perception In Libya, Somaia Suwihli

Graduate Theses and Dissertations

Libya is not considered a highly active seismic region. However, several earthquakes of magnitude >5.0 have occurred there. This dissertation analyzes the seismicity of Libya in order to better understand earthquake hazards, related geomorphic features, and the current evolution of Libyan perceptions of seismic risk. The first article developed a baseline of past and current seismic inventory in Libya, which represented an assessment of Libya seismic hazard by translating, analyzing, and compiling historical sources and archaeological data. This study shows that Libya has experienced earthquakes in varying degrees since ancient times. Through the spatial and temporal distribution of earthquakes from …

Monitoring The 2018 Eruption Of Kīlauea Volcano Using Various Remote Sensing Techniques, Ninad Bhagwat

Graduate Theses & Non-Theses

Monitoring the regions that are prone to natural hazards is essential in disaster management to provide early warnings. Airborne and space-borne remote sensing techniques are cost-effective in accomplishing this task. Interferometric Synthetic Aperture Radar (InSAR) is an advanced remote sensing technique used to detect and measure the changes in the Earth’s topography over time. Spaceborne InSAR is a precise (~mm accuracy) way to measure the land surface altitudinal changes. Persistent Scatterer Interferometry (PSI) is a powerful method of differential SAR interferometry that processes the InSAR data by automatically selecting the persistent scatterers in the region. In this thesis, I developed …

Using Geophysical And Geodetic Data To Improve Natural And Human-Induced Hazard Assessments, Fanghui Deng

USF Tampa Graduate Theses and Dissertations

I use geophysical and geodetic data to study dynamics of the Earth System, including volcanoes and induced seismicity, aiming to improve related hazard assessment at different time and space scales. My dissertation consists of the following three projects: 1) Geophysical model for the origin of volcano vent clusters (Deng et al., 2017). We developed a conceptual model to simulate long-term magma transport to explain the origin of volcanic vent clusters in Quaternary Colorado Plateau volcanic fields. We used density contrast inverted from gravity data to constrain the magma transport model. The development of vent clusters appears to be influenced by …

Sediment Transport And Geomorphological Evolution In The Transgressive Ship Shoal, Louisiana: Insights From Geophysical Observation, Modeling, And Machine Learning Studies, Haoran Liu

LSU Doctoral Dissertations

Ship Shoal has been a high-priority target sand resource for dredging activities to restore the eroding barrier islands in Louisiana, USA. Many studies have been performed in Ship Shoal in recent decades, but our knowledge of temporal and spatial variations of sediment transport and post-dredge morphology is still limited. The objectives of this dissertation are to explore the sediment infilling process, the spatial and temporal evolution of the morphology of dredge pits near and on Ship Shoal by using multiple methods. Scientific methods used in this study include (a) geophysical observation using bathymetry, side-scan and subbottom technique, (b) sediment transport …

Neural Network Models For Nuclear Treaty Monitoring: Enhancing The Seismic Signal Pipeline With Deep Temporal Convolution, Joshua T. Dickey

Theses and Dissertations

Seismic signal processing at the IDC is critical to global security, facilitating the detection and identification of covert nuclear tests in near-real time. This dissertation details three research studies providing substantial enhancements to this pipeline. Study 1 focuses on signal detection, employing a TCN architecture directly against raw real-time data streams and effecting a 4 dB increase in detector sensitivity over the latest operational methods. Study 2 focuses on both event association and source discrimination, utilizing a TCN-based triplet network to extract source-specific features from three-component seismograms, and providing both a complimentary validation measure for event association and a one-shot …

Stress-State And Injection-Rate Dependent Damage Processes During The Hydraulic Fracturing Of Granite, Gayani Sasendrika Gunarathna

Dissertations

Hydraulic fracturing is a well-stimulation technique that is employed in field applications, such as enhanced geothermal systems (EGS) and shale oil/gas extraction. This research experimentally investigates the effect of the state of stress and injection rate on the hydraulic fracturing processes. In addition, a displacement discontinuity method (DDM) code, FROCK, is used to model the crack initiation and propagation in a granite specimen under hydraulic fracturing conditions. In order to conduct the experimental work, a test setup capable of applying a triaxial state of stress and water pressure inside pre-fabricated flaws cut in prismatic granite specimens is developed. Additionally, the …

Soil Moisture Contributions To Insar Phase And Decorrelation, Yusuf Eshqi Molan

Earth Sciences Theses and Dissertations

Interferometric synthetic aperture radar (InSAR) provides capability to detect surface deformation. Between two SAR images, in addition to ground surface deformations, changes may happen in the surface parameters such as soil moisture, vegetation layer water content, and so on. Despite deformation, the other changes may not be of interest for a common InSAR analysis and an ordinary InSAR analysis rarely takes into account their influences on InSAR phase and coherence. The effect of the changes on InSAR phase and coherence can potentially impede accurate estimation of ground surface deformation but also can open new window into soil moisture retrieval and …

Internal Structures And Spin Evolutions Of Small Bodies In The Solar System And Their Geophysical Implications: A Case Study On Ceres, Vesta, And Arrokoth, Xiaochen Mao

Arts & Sciences Electronic Theses and Dissertations

Asteroids and Kuiper belt objects are for the most part the remnant planetesimals that have not been able to form into planets. These small bodies’ evolutionary pathways encode information from the early days of the Solar System. Recent space missions such as Dawn and New Horizons have now made detailed geological investigations of small bodies (i. e. , Ceres, Vesta, and Arrokoth) possible. In this thesis, I use geophysical modeling to study small body internal structure and to investigate spin history under the influence of impacts. I analyze the gravity and shape data obtained by Dawn of Ceres and make …

Seismicity And Shallow Structure At The Mariana Subduction Zone, Melody Eimer

Arts & Sciences Electronic Theses and Dissertations

This dissertation examines the incoming Pacific plate and the overriding forearc at the Mariana Subduction Zone using passive and active source seismology. The incoming plate, with water bound in the plate sediment, crust and mantle, is of interest to help constrain the global water cycle. The seismogenic zone at Mariana is noted for being an aseismic end-member, while extensional faults and active serpentine mud volcanoes characterize the forearc. I use an ocean bottom seismograph (OBS) deployment spanning both the incoming Pacific Plate and the forearc to study the seismicity and shallow structure. The passive source component of the deployment consists …

Crystal Queer: Fracturing The Binaries Of Matter, Creation, And Landscape, Sarah Knight

Graduate School of Art Theses

In this thesis, I compile a series of fragments consisting an analysis of my artwork in the gendered contexts of landscape, self-identity, mythology, and philosophy. I develop my concept of a “queer mark” in my art that serves as a form of queering, a disruption of visual and conceptual cohesion. I form a picture of how our contemporary selves are influenced by our gendered understanding of the landscape through the analysis of philosophical, artistic, and mythological concepts of creation. I see my sculptures as an atlas to an alternative means of understanding identity, a queering of these historical and exclusionary …

Delineating Subsurface Karst Potential Using Electrical Resistivity In The Shell Mountain Province, Fort Hood Military Installation, Texas, Annie Robison

Electronic Theses and Dissertations

Fort Hood Military Installation is located within the Lampasas Cut Plain in Bell and Coryell counties, Texas, and is characterized by exposures of Lower Cretaceous Trinity and Fredericksburg Group carbonates. The Shell Mountain Province is an elevated plateau located in western Fort Hood utilized by the military for heavy mechanical (troop and wheeled) maneuver training and hosts significant surficial and subsurface karst. Ongoing karst inventories in western Fort Hood conducted by range managers have documented over 100 individual karst features. Recent studies utilizing LiDAR and remote sensing techniques delineated karst potential in this area and identified over 13,909 discrete depressions. …

On The Seismic Performance Of Skewed Special Moment Frame Reduced Beam Section Connections, Damaso Daniel Dominguez

Graduate Theses and Dissertations

Special Moment Frames (SMFs) are frequently used in high seismic areas for architecturally constrained designs, as they provide lateral system stiffness without the use of braces which often obstruct views and architectural features. Reduced beam section (RBS) connections are popular SMF connection details developed following the Northridge earthquake to limit brittle fractures within connection welds. Current American Institute of Steel Construction (ASIC) provisions (i.e. AISC 341-16) provide prequalified SMF RBS connection details (including welding requirements); however, all prequalified details only consider orthogonal connections between the beam and column. This dissertation investigates the effect of adding skew within SMF RBS connections …

Development Of Vs Profiles And Site Periods In The Mexico City Basin, Landon Joel Woodfield

Graduate Theses and Dissertations

This study presents dynamic site characterization measurements at 25 sites within the Mexico City Basin. The primary focus of the testing was along the western edge of the Mexico City Basin. At each site, active source Multi-channel Analysis of Surface Waves (MASW) arrays and passive source Microtremor Array Measurements (MAM) L-arrays and circular arrays were used to acquire dispersion data. Horizontal to Vertical Spectral Ratio (HVSR) data was collected to determine site periods at each location. These experimental dispersion data and site periods were fit using a joint inversion of Rayleigh and Love wave dispersion data and HVSR site period …

A Feasibility Study Of Microbialites As Paleomagnetic Recorders, Ji-In Jung

Theses and Dissertations

Microbialites are carbonate organosedimentary deposits formed by benthic microbial communities that trap and bind detrital sediments, and/or inorganic and biologically influenced calcification. Any ferromagnetic particles incorporated into the microbialite structure have the potential to preserve variations in Earth’s magnetic field. A paleomagnetic record in microbialites would be useful for reconstructing the geomagnetic field because it may record at a high temporal resolution based on estimated growth rates, thus preserving relatively short-period variations of the Earth’s magnetic field. In addition, microbialites can be found in the geologic record going back ~3.5 Ga, hence potentially providing information on very ancient variations in …

Joint Inversion Of Gpr And Er Data, Diego Domenzain

Boise State University Theses and Dissertations

Imaging the subsurface can shed knowledge on important processes needed in a modern day human's life such as ground-water exploration, water resource monitoring, contaminant and hazard mitigation, geothermal energy exploration and carbon dioxide storage. As computing power expands, it is becoming ever more feasible to increase the physical complexity of Earth's exploration methods, and hence enhance our understanding of the subsurface.

We use non-invasive geophysical active source methods that rely on electromagnetic fields to probe the depths of the Earth. In particular, we use Ground penetrating radar (GPR) and Electrical resistivity (ER). Both methods are sensitive to electrical conductivity while …

Rayleigh-Wave Multicomponent Crosscorrelation-Based Estimation Of Phase Velocities And Ambient Seismic Source Distributions, Zongbo Xu

Boise State University Theses and Dissertations

One uses seismic interferometry (SI) to recover Green’s functions (i.e. impulse response) from ambient seismic recordings and estimate surface-wave phase velocities to investigate subsurface structure. This method has been commonly used in the last 20 years because this method only utilizes ambient seismic recordings from seismic stations/sensors and does not rely on traditional seismic sources (e.g. earthquakes or active sources). SI assumes that the ambient seismic wavefield is isotropic, but this assumption is rarely met in practice. We demonstrate that, with linear-array spatial sampling of an anisotropic ambient seismic wavefield, SI provides a better estimate of Rayleigh-wave phase velocities than …

Understanding Ice Mixtures Under Pluto Simulated Conditions And Their Implications For Geophysical Processes, Caitlin Joannah Ahrens

Graduate Theses and Dissertations

New Horizons at Pluto has given the planetary science community the first images of Pluto’s surface, including geologic wonders and compositional variability. Methane, nitrogen, and carbon monoxide make up the bulk of the volatile plutonian surface along with water ice. In this work, these three main volatiles are specifically investigated in the laboratory setting to understand the spectral properties and behavior of binary and ternary mixtures. The spectra are taken in the near-infrared wavelengths (1 – 2.5 µm) using Fourier transform infrared (FTIR) spectroscopy techniques utilizing the Pluto Simulation Chamber housed at the University of Arkansas, which can reach conditions …

Stacking The Odds For Better Gpr: An Antenna Comparison, Montana Kruske

Electronic Theses and Dissertations

Ground penetrating radar (GPR) is limited by depth penetration and signal-to-noise ratio (SNR), impacting the ability to resolve subsurface features. Stacking, a process of averaging multiple scans in the same location, improves SNR. Digital antennas are capable of stacking at much higher rates than analog antennas. Four sites were examined using a GSSI SIR-4000 GPR unit with a 400 MHz analog antenna and a 350 MHz digital “hyperstacking” (350 HS) antenna. Sites represent various soil conditions, with known features. Data were compared qualitatively and quantitatively for differences in antenna outputs. Visual inspection of radargrams indicate a reduction in noise in …