Master of Science (MS), Bowling Green State University, 2021, Geology

The Nathrop volcanics are the eroded remnants of domes that formed in the Early Oligocene (~30 Ma) on the edge of the Arkansas graben as part of the Late-Eocene‒Early Oligocene Central Colorado Volcanic Field (CCFV), and are representative of the highly evolved, alkaline, high-silica magmas found in this region associated with the onset of the Rio Grande Rift formation. Two of the edifices, Sugarloaf Mountain and Ruby Mountain, are examined in this study, with new 40Ar/39Ar dates and major and trace geochemistry allowing a comprehensive look at the formation and eruptive history of the domes. Stratigraphic units present at the domes are defined and described, with differences in lithofacies between the domes cataloged as well. The basal unit is a pyroclastic lithic-lapilli tuff (Tnt) overlain by a tuffaceous breccia (Tnb) formed from the autobrecciation of each domes' carapace. The Tnb has two subunits, a vitrophyre (Tnbv) and a perlite (Tnbp) that formed from welding and interactions with groundwater, respectively. The final, uppermost unit is flow-banded rhyolite lavas (Tnr). Three dates determined by the 40Ar/39Ar method using anorthoclase from deposits sourced from Ruby Mountain are indistinguishable within error from each other (30.402 ±0.026; 30.418 ±0.036; 30.454 ±0.040 Ma) but are younger than the two ages measured on sanidine from Sugarloaf Mountain (30.547 ±0.012 and 30.596 ±0.012 Ma). The age distinctions allow for an eruption sequence to be discerned. Geochemical analysis shows overlapping major and trace element chemistry between the domes with REE analyses suggesting fractional crystallization of feldspar to be the cause of most geochemical differences between the domes. Distinct differences in REE concentrations suggest the domes originate from separate magma bodies with a shared source, rather than from a single, chemically zoned magma chamber.

Committee: Kurt Panter Dr (Advisor); John Farver Dr (Committee Member); Jeff Snyder Dr (Committee Member) Subjects: Geochemistry; Geology; Geophysical

Doctor of Philosophy, The Ohio State University, 2021, Geodetic Science

Anthropogenic excessive groundwater depletion (GWD) is a major problem affecting numerous regions in the world that depend on these precious water resources for drinking, irrigation, industrial and urban needs. Climate change is thought to further exacerbate scarcity and degrade the quality of these freshwater resources globally. The Gravity Recovery and Climate Experiment (GRACE) and its successor, GRACE Follow- On (GRACE-FO) twin-satellite gravimetry missions, have been observing the global temporal variations in Terrestrial Water Storage (TWS) for almost two decades at monthly sampling and spatial resolution longer than 333 km (half-wavelength). Innovative methodologies have enabled the retrieval of Groundwater Storage (GWS) anomalies in the world's large climate-stressed aquifers, or disaggregated the signal from satellite gravimetry observed total TWS by removing the surface hydrologic signals via simulated or assimilated hydrologic model output data, or via hydrologic observations. However, uncertainties during the disaggregation process coupled with the limited spatial resolution (666 km grids) of GRACE/GRACE-FO estimated GWS have limited the use of such data for local-scale assessment of GWS variations and for practical applications of water resources management. In this research, we develop and leverage Machine Learning (ML) approach to estimate decadal or longer GW variations for the Central Valley (CV) in California, USA, and North China Plain (NCP) in China, to a local scale (5 km). These two study regions are among the regions in the world, largely dependent on GW for agricultural irrigation and other usages and are currently undergoing severe GWD due primarily to anthropogenic activities and plausibly exacerbated by an increasingly warmer Earth. First, we developed and implemented the robust Artificial Neural Network (ANN) and Random Forest (RF) ML modeling framework in the Central Valley (CV) to study the severe GWD problem using GRACE-derived TW (open full item for complete abstract)

Committee: C.K. Shum (Advisor); Orhan Akyilmaz (Committee Member); Michael Durand (Committee Member); Wei Feng (Committee Member); Ian Howat (Committee Member) Subjects: Geographic Information Science; Geography; Geological; Geophysical; Remote Sensing

Doctor of Philosophy, The Ohio State University, 2020, Geodetic Science

The temporal gravity solutions estimated from NASA/DLR's Gravity Recovery And Climate Experiment (GRACE) mission, and its successor, NASA/GFZ's GRACE Follow-On (GRACE-FO), manifested as mass transports within the Earth system, have been used for a wide variety of Earth Science and climate change studies since 2002. However, there is an around one-year gap between the two satellite gravity missions (2017-2018). ESA's fifth Earth Explorer Mission, the Swarm 3-satellite constellation, equipped with geodetic quality GNSS tracking system, was proposed to fill the gravimetry observation climate record data gap, at a moderate spatial resolution. Here, I applied a modified decorrelated acceleration approach to recover temporal gravity field using the 3-satellite Swarm constellation GPS tracking data. This approach is based on the simple linear relation between the second time derivative of the orbit and the gravitational acceleration. However, the time derivative could highly amplify the noise and make the noise correlated. In addtion, GPS positioning also involves correlation noise. Therefore, two linear transformations were introduced to decorrelate the observation noise. Next, two adjustment methods were studied to optimally combine the three gravity components, namely along-track, cross-track, and radial direction, along with introducing relative weights among orbital arcs for the final optimal gravity field estimation. The Swarm-only temporal gravity solutions have a good to excellent agreement with the overlapping GRACE/GRACE-FO solutions at least up to spherical harmonics degree around 13 (~1500 km, half-wavelength). Swarm-only temporal gravity solutions were then used to fill the mass change data gap over Greenland and West Antarctica ice-sheets during 2017-2018. Over Greenland, Swarm observed mass anomalies agreed well within the time epochs that overlaped with GRACE (correlation coefficient (CC) = 0.62), and GRACE-FO (CC=0.78). Within the data gap year, Swarm ob (open full item for complete abstract)

Committee: C. K. Shum Dr. (Advisor); Michael Bevis Dr. (Committee Member); Ralph von Frese Dr. (Committee Member); Lei Wang Dr. (Committee Member); Dah-Ning Yuan Dr. (Committee Member) Subjects: Geophysical; Geophysics

Master of Science (MS), Ohio University, 2020, Geological Sciences

This study evaluated the use of geophysical well logs to interpret igneous and metamorphic lithologies from the Precambrian basement in east-central Ohio.Geophysical well logs are a staple of the oil and gas industry, but are designed and calibrated for use in sedimentary rocks. Thin-section petrography and X-ray Fluorescence were used to analyze 13 and 16 basement sidewall core samples, respectively, from two wells in Noble and Coshocton counties. The samples were separated into two broad groups on a standard Quartz-Alkali-Plagioclase plot. The Noble county samples were predominantly syenogranites with minor monzogranite and quartz syenite. The Coshocton county samples were more mafic falling into the tonalite, quartz gabbro/anorthosite, and diorite/anorthosite fields. The responses of a suite of geophysical well logs from both wells were compared to the geochemical data in order to determine whether or not the tool response could identify the different crystalline rocks. Gammaray, bulk density, and photoelectric logs were used due to their distinctive responses in sedimentary rocks. Mann-Whitney nonparametric comparisons of well responses showed that the gamma-ray and bulk density responses could delineate lithologies whereas the photoelectric log values could not.

Committee: Daniel Hembree (Advisor); Katherine Fornash (Committee Member); Keith Milam (Committee Member) Subjects: Geochemistry; Geological; Geology; Geophysical; Geophysics; Mineralogy; Petroleum Geology; Petroleum Production; Petrology

Doctor of Philosophy, The Ohio State University, 2020, Earth Sciences

The Greenland Ice Sheet (GrIS) is losing mass at accelerated rates in the 21st century, due in part to faster flow at large outlet glaciers. Chapter 2 presents work published in The Cryosphere (King et al., 2018). Here, we sample rapid changes in thickness and velocity at all large outlet glaciers to derive the first continuous, GrIS-wide record of total ice sheet discharge, or the volume of ice glaciers export, for the 2000-2016 period. We resolve a distinct pattern of seasonal variability with an amplitude of 6%, and analyze how seasonal to annual variability in the discharge time series relates to both meltwater runoff and glacier front position changes over the same period. We find that the annual magnitude of discharge is closely related to cumulative front position change (r2 = 0.79), averaging over 2 km of retreat since 2000. We find that larger seasonal quantities of runoff do not relate to increased annual discharge, although seasonal acceleration of ice discharge does closely coincide with the onset of the melt season. These results suggest that changes in glacier front position drive secular trends in discharge, whereas the impact of runoff is likely limited to the summer months when observed seasonal variations are substantially controlled by the timing of meltwater input. In Chapter 3, we extend our 2000-2016 discharge time series to the period 1985-2018, combining more than three decades of GrIS-wide observational products of outlet glacier velocity, elevation, and front position changes, and compare decadal variability in discharge with calving front position. We find that the close relationship between frontal change and ice discharge identified over the 2000-2016 record holds true for the 34-year record, and that increased glacier discharge can be attributed almost entirely to the retreat of glacier fronts, rather than inland ice sheet processes, such as changes in meltwater runoff. Discharge sensitivity to retreat is remarkably consistent across (open full item for complete abstract)

Committee: Ian Howat (Advisor); Lonnie Thompson (Committee Member); Michael Durand (Committee Member); Bryan Mark (Committee Member) Subjects: Climate Change; Earth; Environmental Studies; Geological; Geophysical; Geophysics

Doctor of Philosophy, The Ohio State University, 2020, Earth Sciences

Fluid flow in the subsurface is a complex phenomenon, significantly affected by geologic characteristics such as porosity and permeability, temperature, compaction, sedimentation, and tectonic processes. The upper crust is often faulted and fractured, and these structural features will alter the inherent geophysical properties of the formations in which they are contained. Because individual techniques used to evaluate crustal fluids, paleo-temperature conditions of formations, and migration pathways each have their own limitations, multidisciplinary approaches must be developed to infer geologic history and past events of fluid flow accurately. In order to interrogate migration pathways and sources of crustal fluids, noble gases have been used to identify mechanisms of fluid flow, hydrocarbon origin, and constrain the temperature conditions of physical processes and chemical reactions. The inert nature and well-constrained sources of noble gases allows them to retain information about geologic history of fluids and rocks over time. Specific isotopic signatures and changes to ratios can distinguish styles of mixing or deformation that occurs during the development of sedimentary basins and orogenic fluid flow. Here, samples collected from the Karoo Basin in South Africa provide an opportunity to analyze the geochemistry of groundwater prior to petroleum exploration. In the Karoo Basin, a field study of the water geochemistry of groundwaters collected before industrial activity showed that naturally-occurring methane was present in the majority of samples and was associated with high salinity and high concentrations of crustal noble gases. The presence of atmospheric noble gases in these samples also suggests fractionation as the natural gas migrated from its source and was emplaced in shallow aquifers. Areas with higher intensity of faulting and fracturing in the Karoo served as preferential pathways during this fluid migration and may still operate that way at pres (open full item for complete abstract)

Committee: Joachim Moortgat (Advisor); Thomas Darrah (Advisor); Franklin Schwartz (Committee Member); David Cole (Committee Member) Subjects: Geochemistry; Geological; Geophysical; Geophysics

Doctor of Philosophy, The Ohio State University, 2020, Geodetic Science

To improve on the understanding of Earth dynamics, a perturbation theory aimed at geopotential recovery, based on purely kinematic state vectors, is implemented. The method was originally proposed in the study by Xu (2008). It is a perturbation method based on Cartesian coordinates that is not subject to singularities that burden most conventional methods of gravity recovery from satellite-to-satellite tracking. The principal focus of the theory is to make the gravity recovery process more efficient, for example, by reducing the number of nuisance parameters associated with arc endpoint conditions in the estimation process. The theory aims to do this by maximizing the benefits of pure kinematic tracking by GNSS over long arcs. However, the practical feasibility of this theory has never been tested numerically. In this study, the formulation of the perturbation theory is first modified to make it numerically practicable. It is then shown, with realistic simulations, that Xu's original goal of an iterative solution is not achievable under the constraints imposed by numerical integration error. As such, a non-iterative alternative approach is implemented, instead. Finally, the principles of this modified procedure are applied to the Schneider (1968) model, improving the original model by an order of magnitude for high-low satellite-to-satellite tracking (SST). The new model is also adapted to the processing of low-low SST, and a combination thereof, i.e. GRACE-like missions. In validating the linearized model for multiple-day-long arcs, it is revealed (through simulated GRACE-like orbits) to be at least as accurate as (or in some cases better than) the GRACE K-band range-rate nominal precision of 0.1 μm/s. Further application of the model to simulated recovery of spherical harmonic coefficients is shown to achieve accuracies commensurate to other models in practice today.

Committee: Michael Durand (Advisor); Christopher Jekeli (Advisor); Steven Lower (Committee Member) Subjects: Applied Mathematics; Earth; Geophysical; Geophysics; Statistics

Master of Science, Miami University, 2019, Geology and Environmental Earth Science

Induced seismicity has become a major issue with the increase in both hydraulic fracturing and disposal of leftover wastewater. Regulatory methods such as traffic light systems mitigate the impact of induced events, but do not predict when and where they will occur. Previous methods to identify induced seismicity (e.g. Caffagni et al., 2016; Yoon et al., 2015; Beauce et al. 2017) are effective, but require heavy computational requirements and/or multiple sensors to produce viable results. A computationally efficient Repeating Signal Detector (RSD) was recently developed to identify similar waveforms in continuous seismic data using a single seismometer. Instead of relying on a priori templates, RSD identifies repeating signals of interest (SoI) and then performs agglomerative clustering, resulting in a significantly faster processing time than other approaches. However, as RSD detects any repeating signal, not limited to earthquakes, the current study focuses on distinguishing repetitive seismicity from repetitive noise. In Central-eastern Ohio, the most effective approach has been to apply discriminants to resulting families post-cross-correlational routine, while in Southeastern Ohio, culling the SoI prior to clustering has been most effective. The successful methods for discrimination we constructed were based on signal characteristics such as relative amplitudes and correlation coefficients between components.

Committee: Michael Brudzinski (Advisor); Brian Currie (Committee Member); Carrie Tyler (Committee Member) Subjects: Geological; Geology; Geophysical; Geophysics

Master of Science in Engineering, University of Akron, 2019, Civil Engineering

Evaluation of subsurface conditions in Northeastern Ohio generally consists of geotechnical investigations resulting in information about the soil conditions and NSPT values to describe the subsurface. While it is recognized that shear wave velocity is the most accurate parameter for determining site response during seismic activity, determining the Vs of a site is generally too significant of a cost with respect to average project budgets. Engineers often draw conclusions about the expected geophysical behavior of a site based upon the geotechnical data, the NSPT value. Correlation equations have been developed in many different regions of the globe to aid engineers in understanding the expected seismic response of a site without requiring a geophysical survey be performed. The purpose of this study is to develop an equation between shear wave velocity (Vs) and N-value (NSPT), which would allow local engineers to determine a site's seismic response and allow for seismic site classification. Geological conditions in the region consist of glacial features and loamy soils composed of mostly clays, silts and then sands. Geotechnical data was collected for this research using a drill rig and standard penetrating testing method. Geophysical data was collected using single station surface wave refraction method. The data collection established a set of 275 data pairs that were used in a simple linear regression to determine the relationship between the two parameters Vs and NSPT. The data set was considered as a whole for all soil types, as well as being separated into subsets to allow the derivation of equations based upon soil type. The coefficients from the regression analysis were fitted to the established power model used in similar research, and three equations were determined. The resulting equations in (m/s) are: Vs=334.7NSPT0.024 for all soil types (R2=0.863), Vs=319.2NSPT0.029 for sandy soils (R2=0.840), Vs=328.8NSPT0.030 for clayey soils (R2 = (open full item for complete abstract)

Committee: Teresa J. Cutright PhD (Advisor); William H. Schneider PhD (Committee Member); Ala R. Abbas PhD (Committee Member) Subjects: Civil Engineering; Engineering; Geophysical; Geotechnology

Master of Science (MS), Wright State University, 2019, Earth and Environmental Sciences

This study focuses on northern Terre Haute, Indiana, where seven 2D seismic reflection time sections were collected by CountryMark and donated to Wright State University. Geologically, the area is on the eastern margin of the Illinois Basin. Two of these seismic lines display significant relief along a continuous, high-amplitude horizon approximately 180 milliseconds in two-way traveltime depth. This horizon was previously interpreted by CountryMark to be a Silurian reef core of the type common in this region of the Illinois Basin; however, other seismic lines within the data set display no relief. Furthermore, borehole logs within the area show no such relief at the equivalent depth of around 1700 feet. Therefore, the apparent structural high is an artifact within the two seismic lines, and can be called velocity pull-up. Various analyses were conducted to examine the causes of this velocity pull-up. The near-surface, within this region, contains many surfaces that may give rise to a velocity pull-up, including (1) the layer of weathered Pennsylvanian bedrock; (2) the Mississippian-Pennsylvanian Unconformity; and (3) an unconformity within Pennsylvanian section. It is possible that each of these surfaces could have enough relief to induce the observed velocity pull-up, and these possibilities were evaluated utilizing a combined analysis of Bouguer gravity, first-arrival traveltime tomography, passive seismic, and well log correlation. These multiple analyses show there is no Silurian reef core but a more complex velocity-inducing feature from a combination of the Mississippian-Pennsylvanian Unconformity and a shallower paleovalley fill.

Committee: Ernest C. Hauser Ph.D. (Committee Chair); Doyle R. Watts Ph.D. (Committee Member); David F. Dominic Ph.D. (Committee Member) Subjects: Geographic Information Science; Geology; Geophysical; Geophysics

Master of Science, The Ohio State University, 2019, Earth Sciences

The 182Hf-182W isotope system is ubiquitously employed for core chronometry in planets and planetesimals. However, interpretations of experimental 182W measurements rely on vast assumptions about the metal-silicate W partitioning history with the body in question, as well as the initial concentration of 182Hf. Therefore, the simple models that couple with these assumptions may produce erroneous interpretations of the ages of cores. Here, I produce core formation models within the asteroid 4-Vesta to test existing assumptions around the ϵ^182 W of bulk Vesta and the Vestian core. I find that a eucritic ϵ^182 W in the Vestian mantle in not reconcilable with a chondritic ϵ^182 W within bulk Vesta across existing fO2 models for the Vestian magma ocean. My models predict a Vestian core with a strongly negative ϵ^182 W, implying that the Vestian core is enriched in 184W relative to 182W. The resulting bulk Vesta ϵ^182 W is >1400 units below the chondritic value. To test assumptions around W equilibrium and implications for Earth's iron rain, I also produce 99% chemical equilibrium models for a Vestian and Earth magma ocean. I find that Vesta's iron rain reaches 99% chemical equilibrium with the Vestian magma ocean in <613 m and Earth's iron rain reaches 99% chemical equilibrium with Earth's magma ocean in <62 m. However, given a reverse in partitioning behavior >80 km below the surface of Earth's magma ocean, removal of W from Earth's magma ocean may be inhibited if impactor cores do not efficiently disperse their iron cores into droplets of stable size. Such a scenario could provide a solution to the Earth's mantle excess siderophile problem as it pertains to W.

Committee: Wendy Panero (Advisor); Steven Lower (Committee Member); W. Ashely Griffith (Committee Member) Subjects: Earth; Geochemistry; Geology; Geophysical; Geophysics

Doctor of Philosophy, The Ohio State University, 2019, Earth Sciences

Tide gauges record relative sea level (RSL), i.e. the vertical position of the sea surface relative to the adjacent land mass or relative to the seafloor under the gauge. A tide gauge cannot distinguish between a rise in sea level or subsidence of the land or seawall or pier that supports the gauge. Absolute sea level (ASL) refers to the level or height of the sea surface stated in some standard geodetic reference frame, e.g. ITRF2008. Since satellite altimeters make a geometrical measurement of sea level, this constitutes a determination of ASL. Satellite altimeters suffer from instrumental drift and thus need to be calibrated using tide gauges. This requires us to estimate the rate of RSL change at each tide gauge and convert this into an estimate of the rate of ASL change. This is done using a GPS station located at or near the tide gauge, since it can measure the vertical velocity of the lithosphere – often referred to as vertical land motion, VLM – which allows us to exploit the relationship ASL = RSL + VLM. This goal has motivated geodesists to build dozens of continuous GPS (or CGPS) stations near tide gauges – an agenda sometimes referred to as the CGPS@TG agenda. Unfortunately, a significant fraction of all long-lived tide gauges – especially those in the Pacific - have also recorded non-steady land motion caused by earthquakes. Rather than simply delete such datasets from the agenda, this thesis explores a new analytical method, based on the concept of a geodetic station trajectory model, that allows us to compute RSL and ASL rates even at tide gauges affected by regional earthquakes. We illustrate this method using two tide gauges (PAGO and UPOL) and three GPS stations (ASPA, SAMO and FALE) located in the Samoan islands of the Southwest Pacific. In addition to managing the impact of large regional earthquakes, we also seek new approaches to reducing noise in RSL rate estimates by suppressing the higher frequency sea level changes associated with ocean (open full item for complete abstract)

Committee: Michael Bevis (Committee Chair); C.K. Shum (Committee Member); Loren Babcock (Committee Member); Michael Barton (Committee Member) Subjects: Earth; Geological; Geophysical; Geophysics; Geotechnology; Ocean Engineering; Oceanography

Master of Science (MS), Wright State University, 2018, Earth and Environmental Sciences

This study analyzes ten 2D seismic lines donated by CountryMark together with potential field data to examine the upper crustal structure near Wabash, Indiana. These seismic profiles reveal significant relief of the Precambrian Unconformity and prominent upper crustal reflections. The Precambrian Unconformity interpreted from the unmigrated stacked seismic sections is characterized by undulations and bowtie artifacts. Zero offset seismic models constructed using profiles of the exposed Precambrian Unconformity across the Eastern Granite-Rhyolite Province outcrops of the St. Francois Mountains feature the same seismic expression. The upper crust below the Precambrian Unconformity on the Countrymark seismic sections is also characterized by discontinuous high-amplitude reflections that occur ~0.5s two-way time below the Precambrian Unconformity. The distribution of these upper crustal reflections on a time structure map correlates with positive magnetic and gravity anomalies suggesting the reflectors are likely mafic. These geophysical observations are consistent with a scenario like that interpreted for the evolution of the Precambrian rocks of the St. Francois Mountains and also the findings of McBride et al. (2016) for patterns of reflections on seismic lines in central Illinois.

Committee: Ernest Hauser Ph.D. (Committee Chair); Doyle Watts Ph.D. (Committee Member); David Dominic Ph.D. (Committee Member) Subjects: Earth; Geology; Geophysical; Geophysics

Master of Science, The Ohio State University, 2018, Earth Sciences

The Ordovician-aged Point Pleasant Formation is an economically important unconventional oil and gas play in the Appalachian Basin, in particular Ohio, western Pennsylvanian and West Virginia. The Point Pleasant Formation is known to have overpressured pore fluids, that is, pore pressure above hydrostatic conditions. Overpressure is an important rock property to constrain because it exerts a strong control on the mechanical stability of boreholes, the response of the formation to hydraulic fracture stimulation, and volumetric flow rates of produced fluids. However, what is not well known is the spatial distribution, magnitude, and controls on the overpressure within the Point Pleasant Formation. In this study, pore pressure in the Point Pleasant Formation is estimated based on sonic velocity geophysical logs measured in 33 wells as well as mudweight data from 23 wells. From this analysis, a map of overpressure in the Point Pleasant identifies a large area of overpressure centered in southeastern Ohio primarily within the counties of Noble, Monroe, and Washington . This overpressure map may facilitate target selection, safer drilling, and more successful well completions. Areas of significant overpressure have also been linked to enhanced risks of induced seismic events, thus the overpressure map may also indicate areas that have higher probability to trigger induced seismic events during hydraulic fracturing or waste water disposal.

Committee: Derek Sawyer (Advisor); Cook Ann (Advisor) Subjects: Geological; Geology; Geophysical; Geophysics

Doctor of Philosophy, The Ohio State University, 2017, Geodetic Science and Surveying

As the largest low-lying river delta in the world, located at the confluence of the mighty Ganges-Brahmaputra-Meghna rivers, and as one of the most densely populated countries with more than 163 million people, Bangladesh already faces tremendous vulnerability. Accelerated sea-level rise, along with tectonic, sediment load and groundwater extraction induced land uplift/subsidence, have exacerbated Bangladesh's coastal vulnerability. Climate change has further intensified these risks with increasing temperatures, greater rainfall volatility, and increased incidence of intensified cyclones and cyclone-induced storm surges, in addition to its seasonal transboundary monsoonal flooding, tides, large seasonal river discharges along with the associated sediment transport causing load/compaction of the coastal regions. As a result, Bangladesh coastal region has become the most dynamic region with the highest erosion and accretion rate in the world. For decades, the shape of the shoreline has changed greatly affecting millions of people living in the region. Our objective is to quantify the long-term or multi-decadal, seasonal shoreline changes for coastal Bangladesh to assess the impacts of the complex geophysical and climatic processes. In this study, the shoreline from 1970's to the year 2017 are extracted from a four-decade time-series of Landsat imagery. An automated shoreline extraction method based on Google Earth Engine (GEE) Application Programming Interface (API) is developed and applied to quantify Bangladesh coastal shoreline changes. This method involves Normalized Difference Water Index/Modified Normalized Water Index (NDWI/MNDWI) and the Otsu Threshold Method to enhance the accuracy of the digital imagery processing. The extracted Landsat imagery shorelines in three example regions are validated by comparing with independent DigitalGlobe and with CNES/Airbus higher resolution imagery at several m using Google Earth (GE). We concluded that the extracted Land (open full item for complete abstract)

Committee: Che-Kwan Shum (Advisor); Michael Thomas Durand (Committee Member); Alan John Saalfeld (Committee Member) Subjects: Earth; Geophysical

Master of Science (MS), Wright State University, 2017, Earth and Environmental Sciences

During the summer of 2015 a 2D seismic line (WSU-2015), ~2.3km long, was collected by Wright State University along Watson Road, south of London, Ohio. This seismic line is parallel to and approximately ¼ km south of `Line 6' of Mayhew (1969), which is one of six analog, single-fold seismic lines within the area that he studied. The focus of this research is to interpret the stratigraphy revealed by the new seismic line, especially to evaluate the existence or otherwise of a fault that Mayhew (1969) inferred in his interpretation. An important step in this new interpretation was to construct a synthetic seismogram using sonic and density logs from nearby boreholes. Mayhew's (1969) interpretation of a fault was based largely upon an abrupt change of regional dip and an interpreted diffraction near the top of what he interpreted as the Conasauga Formation. However, my interpretation is that the Conasauga Formation is unfaulted but does exhibit significant lateral facies changes. The way these changes were expressed on the older, single-fold, analog seismic data may have contributed to Mayhew's (1969) interpretation of a fault. This result raises questions about four other faults that were interpreted by Mayhew (1969) and have been included on the geological map of Ohio.

Committee: Ernest Hauser Ph.D. (Committee Chair); Doyle Watts Ph.D. (Committee Member); David Dominic Ph.D. (Committee Member) Subjects: Geophysical

Master of Science, The Ohio State University, 2017, Earth Sciences

The interplay of tectonics and climate is recorded in the sedimentary strata within the Victoria Land Basin, McMurdo Sound, Antarctica. Patterns of Cenozoic sedimentation are documented from interpretation of seismic reflection profiles calibrated by drillhole data in McMurdo Sound. These patterns provide enhanced constraints on the evolution of the coupled Transantarctic Mountains-West Antarctic Rift System and on ice sheet advance/retreat through multiple climate cycles. Revised seismic mapping through McMurdo Sound has been completed, utilizing the seismic stratigraphic framework first established by Fielding et al. (2006) and new reflectors marking unconformities identified from the AND-2A core (Levy et al., 2016). Correlations between the two frameworks update age constraints for the initiation of the Terror Rift, which was previously interpreted to have begun ~13 Ma based on age assignments made by Wilson et al. (2012) in the AND-1B core. New observations indicate the Terror Rift could have initiated as early as ~20 Ma, and was well underway by ~18 Ma, taking into account interval thickness patterns and new age assignments for reflector surfaces. The new age framework for seismic reflectors also raises the possibility of down-to-the-east normal faults underneath Hut Point Peninsula, in order to reconcile ~13 Ma and younger ages in the AND-1B core with McMurdo Sound seismic stratigraphy. Seismic facies correlated to the AND-2A core were mapped throughout McMurdo Sound. The strongest control on these facies was Miocene water depth. Facies patterns suggest that the shelf-slope-basin geometry within McMurdo Sound did not shift laterally throughout the Miocene, and was very similar to the present morphology. The mapped extent of erosion features indicates that grounded ice did not extend from the south throughout McMurdo Sound until ~14.4 Ma. Prior to that point, erosion was limited to the western shelf as ice extended eastward from TAM outlet glaciers. U (open full item for complete abstract)

Committee: Terry Wilson (Advisor); Lawrence Krissek (Committee Member); Derek Sawyer (Committee Member) Subjects: Geological; Geology; Geophysical; Geophysics

Master of Science, The Ohio State University, 2017, Earth Sciences

Turbidite channels are important conduits of clastic sediments into the deep ocean, with coarser-grained deposits creating potential reservoirs for hydrocarbons. In this study, three-dimensional seismic data and borehole logs from three industry wells were used to interpret channel systems, lithology, and overall depositional trends in the Orca and Choctaw mini-basins, located on the outer continental slope in the Gulf of Mexico in ~1645-2470 m (5400-8400 ft) of water. These mini-basins have previously been shown to have strong indications of gas hydrate in core samples and geophysical data, and the primary goal of this study was to identify coarse-grained sediments within channel systems that could serve as potential hydrocarbon reservoirs. To accomplish this, thirty-five channels were mapped in the ~2900 m (9500 ft) of sediment between the seafloor and top of salt. Channels were grouped into two broad morphological types to predict where coarse-grained sediments within each system were likely to occur. Basin depositional trends were also assessed to show how progressive salt withdrawal impacts channel occurrence by shifting topographic lows, in turn influencing where coarse-grained sediments are ultimately deposited. This research provides a detailed assessment of the turbidite channel systems in the Orca and Choctaw basins, and serves as model for future studies using seismic and well log analysis to interpret turbidite channel systems in deepwater basins.

Committee: Derek Sawyer (Advisor); Ann Cook (Committee Member); Mike Wilkins (Committee Member) Subjects: Earth; Geological; Geology; Geomorphology; Geophysical; Geophysics

Master of Science, University of Akron, 2017, Geology

A Griggs rig apparatus was used to perform a number of strain rate stepping and pressure stepping experiments of O+ oriented synthetic quartz crystals. These samples were annealed at 1 atm and 900°C for 24 hours to convert the gel type water inclusions to free water inclusions similar to those that are found in natural milky quartz. Strain rate stepping experiments were performed at temperatures from 1000°C to 750°C, and strain rates from 1.6 X 10-4 s-1 to 1.6 X 10-6s-1, while confining pressure was held constant at 1.5 GPa. These samples were observed to yield over a range of <10 to ~300 MPa in many cases, though under some of the conditions tested samples did not yield. Two pressure stepping experiments were performed, one at 800°C and one at 750°C, with a strain rate of 1.6 X 10-6s-1 and confining pressures between 0.6 GPa and 1.5 GPa. The sample strengths measured in the pressure stepping experiments were between ~30 MPa and ~60 MPa. Microstructures observed within deformed samples include undulatory extinction and deformation lamellae. The mechanical data from those experiments that were consistent with dislocation creep fit the flow law: ε′=0.00177*CH2O1.9*fH2O* ςdiff3.29* e(-268.6/(R*T)) Under natural conditions, this suggests plastic yielding of quartz occurs at ~9 km (~225°C) deep in the crust.

Committee: Caleb Holyoke III (Advisor); LaVerne Friberg (Committee Member); John Peck (Committee Member) Subjects: Geology; Geophysical; Geophysics

Master of Science (MS), Wright State University, 2016, Earth and Environmental Sciences

The reprocessing of four vibroseis seismic reflection lines at the AK Steel facility in Middletown, Ohio, provides new insight on the age, deposition, and structural deformation of the pre-Mount Simon sedimentary sequence below Butler and Warren Counties. Processing was focused on the pre-Mt. Simon reflections to reveal gently west-southwest dipping reflectors that make a slight angular unconformity with the overlying Paleozoic sedimentary strata. This pre-Mount Simon sedimentary sequence has been encountered in several wells from western Ohio, Indiana, and northern Kentucky and has been identified as the Middle Run Formation. Examination of the weak and discontinuous seismic character of the reflections from the Middle Run Formation on these AK Steel lines suggests that the Middle Run Basin here is apparently deep and sits above strong, continuous reflectors that are parallel to the overlying reflections from within the Middle Run. However, the gentle dip of the Middle Run exhibited at the AK Steel location contrasts greatly with the Middle Run Formation and deeper rocks to the east, as observed in the Warren County Line ODNR-1-88. There the Middle Run Formation exhibits a moderate apparent east-dip below an angular unconformity with the overlying Mt. Simon Sandstone, and the Middle Run Formation has been erosionally removed at the western end of the Warren County seismic line. The structures exhibited by these seismic lines suggest the likely presence of a fault between the AK Steel lines and the ODNR-1-88 line, with the thicker Middle Run sequence and gently dipping reflections on the AK Steel lines being best explained by preservation in a downthrown block, followed by subsequent erosion. The structural pattern of these lines suggest this fault is a Grenville reverse fault. The age and setting of the Middle Run Formation has been a subject of controversy. However, recent workers have provided new evidence that suggests that the Middle Run Formation fro (open full item for complete abstract)

Committee: Ernest Hauser Ph.D. (Advisor); Doyle Watts Ph.D. (Advisor); David Dominic Ph.D. (Committee Member) Subjects: Geological; Geology; Geophysical; Geophysics