Geophysics and Seismology Commons^™

Atmospheric And Ionospheric Responses To Acoustic And Gravity Waves Driven By Earthquakes And Tsunamis, Pavel A. Inchin

Doctoral Dissertations and Master's Theses

Natural hazards (NHs) are causes for significant concern due to their potentially catastrophic impacts on society. The study of their effects on the upper atmosphere can provide significant insight into the coupled nature of geophysical processes, and drives important applications for radio communication and navigation, leading potentially to the development of NH early-warning systems. Although general concepts underlying their coupling mechanisms are well understood, recent computational capabilities, supported by high temporal and spatial density of observations, have reached the level where such processes can be modeled with unprecedented realism for detailed case studies. The studies provided in this thesis are …

Abiotic Formation Of Dissolved Organic Sulfur In Anoxic Sediments Of Santa Barbara Basin, Hussain A. Abdulla, David J. Burdige, Tomoko Komada

OES Faculty Publications

Sulfurization has been found to enhance organic matter preservation and petroleum formation in marine sediments. However, we do not yet have a comprehensive understanding of sulfurization mechanisms. In this study, we investigated several possible mechanisms of dissolved organic sulfur (DOS) formation in the top 4.5 m of anoxic sediments of Santa Barbara Basin (SBB), California Borderland. Using Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FTICR-MS), we identified chemical formulas of potential dissolved organic matter (DOM) precursors to these DOS compounds. We also examined how the formulas of abiotically formed DOS changed as a function of depth across a major redox …

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 …

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 …

Effect Of Subsurface Microseismicity On The Motion Of Surrounding Dispersed Droplets: Supporting Information, Chao Zeng, Wen Deng

Research Data

The human-induced seismicity has called substantial attention in recent years. The effect of seismicity on the subsurface structure has been extensively studied. However, the effect of seismicity, especially those microseismicity, on surrounding immiscible fluids is rarely investigated. In porous media with two or more immiscible fluids, different amplitudes of vibration induced by seismicity have distinct effects on the dynamic behavior of fluids. Three types of pore-scale models are prevalent in the analysis of the motion of immiscible droplets. The underlying assumptions and accuracy of these models are compared in this study in both frequency domain and time domain. The frequency …

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 …

A Machine Learning And Data-Driven Prediction And Inversion Of Reservoir Brittleness From Geophysical Logs And Seismic Signals: A Case Study In Southwest Pennsylvania, Central Appalachian Basin, Tobi Micheal Ore

Graduate Theses, Dissertations, and Problem Reports (ETD)

In unconventional reservoir sweet-spot identification, brittleness is an important parameter that is used as an easiness measure of production from low permeability reservoirs. In shaly reservoirs, production is realized from hydraulic fracturing, which depends on how brittle the rock is–as it opens natural fractures and also creates new fractures. A measure of brittleness, brittleness index, is obtained through elastic properties of the rock. In practice, problems arise using this method to predict brittleness because of the limited availability of elastic logs.

To address this issue, machine learning techniques are adopted to predict brittleness at well locations from readily available geophysical …

Onset And Cause Of Increased Seismic Activity Near Pecos, West Texas, United States, From Observations At The Lajitas Txar Seismic Array, Clive Frohlich, Chris Hayward, Julia Rosenblit, Chastity Aiken, Peter Henning, Alexandros Savvaidis, Casee Lemons, Elizabeth Horne, Multiple Additional Authors

Geology Faculty Publications and Presentations

In recent years, numerous small earthquakes have occurred near the town of Pecos in West Texas; however, when this activity began and whether it was caused by increased petroleum industry activity has been uncertain because prior to 2017 there were few permanent seismograph stations in the region. We identify and locate earthquakes using data recorded since 2000 at TXAR, a sensitive 10‐station seismic array situated about 240 km south of Pecos. We thus show that in 2007, one earthquake occurred near Pecos, in 2009 several more occurred, and subsequently, activity has increased considerably, with more than 2000 events identified in …

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 …

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 …

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 …

Effect Of Subsurface Microseismicity On The Motion Of Surrounding Dispersed Droplets -- Data, Chao Zeng, Wen Deng

Effect of Subsurface Microseismicity on the Motion of Surrounding Dispersed Droplets – Data

Spreadsheet - Data plotted in Figure 4 and Figure 5

Supporting information

Evolution And Stratigraphic Architecture Of Tidal Point Bars With And Without Fluvial Input: Influence Of Variable Flow Regimes On Sediment And Facies Distribution, And Lateral Accretion, Pricilla Souza

LSU New Orleans Theses and Dissertations

Tide-influenced point bars represent a significant proportion of shallow-marine deposits, commonly developed along meandering channels in most backbarrier and estuarine systems. However, sedimentological studies to characterize this type of deposit are still emerging. They often present very heterogeneous internal architectures which development is controlled by the complex flow patterns operating in tidal environments. The study of the sedimentological and morphological characteristics of these features provides better understanding of the hydrodynamic processes that shape coastal systems and control their evolution as well as it contributes to better reservoir potential prediction and production strategy optimization, as tidal point bars may represent hydrocarbon …

Examination Of Maskelynite Through Static Recompression And Dynamic Compression, Justin James Reppart

UNLV Theses, Dissertations, Professional Papers, and Capstones

This is an experimental study that aims to clarify the possible formation mechanisms of maskelynite. Maskelynite is a diaplectic glass, that forms during shock compression of feldspar far below the melting point, and without fusion. Maskelynite also paramorphises precursor feldspar grains. Maskelynite is an important probe of shock-pressures at terrestrial impact sites and in many meteorites. Two mechanisms of formation of maskelynite are examined here: 1) maskelynite is result of a pressure-induced amorphization of feldspar compressed beyond its mechanical stability where the formation of thermodynamically stable phases is kinetically inhibited [1, 2]. 2) Feldspar transforms upon dynamic compression into a …

Using Archaeological Remote Sensing To Evaluate Land Use And Constructed Space In Chaco Canyon, Jennie Odessa Sturm

Anthropology ETDs

Archaeological remote sensing includes a suite of non-invasive methods that can be used to study elements of the archaeological record that may not be achievable otherwise. Using primarily geophysical remote sensing, and especially ground-penetrating radar (GPR), three studies involving questions of “use” were conducted in Chaco Canyon, New Mexico. The first used GPR to study the built interior features of a single room in Pueblo Bonito to evaluate use and function of that room. Three categories of features were identified in the GPR data and confirmed with subsequent excavation. The second study used GPR to re-evaluate an enigmatic land use …

Crustal Structure Beneath The East Coast Magnetic Anomaly From Seismic Refraction Tomography, Collin C. Brandl

Earth and Planetary Sciences ETDs

Syn-rift igneous addition is necessary for successful continental breakup. Past investigations of passive margins have focused on strike perpendicular structure, but potential field anomalies indicate that significant crustal variations may be present. Data from 21 ocean bottom seismometers was acquired as part of the Eastern North American Margin Community Seismic Experiment and was used for tomographic inversion to create 2D velocity models of the margin that are representative of crustal structure. Crustal thickness varies along-strike from ~20 km to ~24 km and a high velocity (Vp > 7 km/s) layer is present at the base of the crust above the Moho. …

The Community Outreach Model Of Service-Learning: A Case Study Of Active Learning And Service-Learning In A Natural Hazards, Vulnerability, And Risk Class, Brittany D. Brand, Kara Brascia, Margaret Sass

Geosciences Faculty Publications and Presentations

The popularity of service learning is increasing, especially at a time when college students want to make a greater impact in their communities. However, service learning has not been extensively assessed in courses based in science, technology, engineering, and mathematics. This article provides a case study of how incorporating service learning through a community outreach project can increase student engagement, enhance the depth of understanding of a given topic, build communication and teamwork skills, and contribute meaningfully to the students' community. This article shares how the instructor of a natural hazards, vulnerability, and risk course implements service-learning through a community …

Crevasse Initiation And History Within The Mcmurdo Shear Zone, Antarctica, Lynn Kaluzienski, Peter Koons, Ellyn Enderlin, Gordon Hamilton, Zoe Courville, Steven Arcone

Geosciences Faculty Publications and Presentations

While large-scale observations of intensified fracture and rifting can be observed through remote-sensing observations, understanding crevasse initiation may best be achieved with small-scale observations in which crevasses can be directly observed. Here we investigate the kinematic drivers of crevasse initiation in the McMurdo Shear Zone (MSZ), Antarctica. We delineated 420 crevasses from ∼95 km of 400 MHz frequency ground-penetrating radar data and compared these data with kinematic outputs derived from remotely-sensed ice surface velocities to develop a statistical method to estimate crevasse initiation threshold strain rate values. We found the MSZ to be dominated by simple shear and that surface …

Incorporating Geophysical Data In Slope Stability Modeling For Two Slopes In Arkansas, Vanessa Lebow

Graduate Theses and Dissertations

Slope failures in the United States alone cause millions of dollars in damage to infrastructure, threaten national monuments, create environmental hazards, and take an average of 25-50 lives a year. With the inevitable construction that occurs on slopes, it is imperative that the slopes be properly designed which requires a thorough understanding of slope grade, subsurface soil conditions, soil strength parameters, water table locations, and depth to bedrock across the entire site. The preferred method of data collection would be to use borings and other in-situ methods; however, sometimes due to cost constraints or site accessibility only a very limited …

Informing Field Management Decisions To Enhance Alfalfa Seed Production Using Remote Sensing, Thomas V. Van Der Weide

Boise State University Theses and Dissertations

The development rate of alfalfa seed crop depends on both environmental conditions and management decisions. Crop management decisions, such as determining when to release pollinators to optimize pollination, can be informed by the identification of plant development stages from remote sensing data. I first identify what electromagnetic wavelengths are sensitive to alfalfa plant development stages using hyperspectral data. A Random Forest regression is used to determine the best Vegetation Index (VI) to monitor how much of the plant is covered in flower. The results indicate that Blue, Green, and Near-Infrared are the important electromagnetic wavelengths for the VI. Imagery collected …