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TROTTER, BENNETTPore Pressure Prediction in the Point Pleasant Formation in the Appalachian Basin, in parts of Ohio, Pennsylvania, and West Virginia, United States of America
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

Ramanayaka Mudiyanselage, AsangaAnalyzing vertical crustal deformation induced by hydrological loadings in the US using integrated Hadoop/GIS framework
Master of Science in Applied Geospatial Science, Bowling Green State University, 2018, Geology
Vertical crustal deformation for the contiguous US was assessed using continuous GPS stations for a total of 54 months. The study analyzed the correlation of vertical crustal deformation and hydrological loadings. Precipitation data were used as a measure of surface hydrological loadings. The relationship of GPS and precipitation data was studied by deriving Pearson correlation coefficients (r) for four different levels of watersheds (HUCs). To process the data for the temporal analysis, this study presents a prototype Hadoop/GIS framework which supports integrating distinct types of data. GPS data and precipitation data were analyzed by Hadoop and Hive which runs on the configured multi-node cluster. The spatial analysis used GIS tools to produce correlation maps. GRACE data which measure the terrestrial water storage were used to validate results. The generated correlation coefficients suggest that in the Northwestern US, the GPS deformation is negatively correlated with precipitation data. For instance, many watersheds in Washington and Oregon states produced high negative correlations (r) (between -0.55 and -0.75) which indicates the driving factor for vertical crustal deformation in the North-Western US is hydrological loadings which may have resulted from elastic loading processes. At the same time, GPS-GRACE correlation coefficients show a reasonable agreement with GPS-precipitation correlations for the North-Western US (r = - 0.67, r = - 0.69). However, the observed correlation coefficients for some of the watersheds in the Central Valley of California, Pennsylvania, and Maryland states had moderate positive values (r = 0.52, r = 0.42) which may have resulted from other factors such as climatic conditions, geological and geophysical effects.

Committee:

Peter Gorsevski, Ph.D. (Advisor); Yuning Fu, Ph.D. (Committee Member); Jeffrey Snyder, Ph.D. (Committee Member)

Subjects:

Geographic Information Science; Geography; Geophysics; Information Science; Information Technology

Keywords:

Geoinformatics; Crustal Deformation; Hydrological Loadings; Geospatial Analysis; GPS; Precipitation; GRACE; GIS; Hadoop; Hive; Bigdata Analytics

Green, Michael RayGeophysical Exploration of the Upper Crust Underlying North-Central Indiana: New Insight into the Eastern Granite-Rhyolite Province
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

Keywords:

geophysical; Eastern Granite-Rhyolite Province; seismic profiles; seismic lines; Precambrian Unconformity

Munk, JensAn equivalent source inversion method for imaging complex structures /
Doctor of Philosophy, The Ohio State University, 1999, Graduate School

Committee:

Not Provided (Other)

Subjects:

Geophysics

van Cleef, Garrett WarrenZonal winds between 25 and 120 km retrieved from solar occultation spectra /
Doctor of Philosophy, The Ohio State University, 1989, Graduate School

Committee:

Not Provided (Other)

Subjects:

Geophysics

Valizadeh-Alavi, HedayatollahPattern analysis of benthic boundary layer momentum and sediment transport /
Doctor of Philosophy, The Ohio State University, 1983, Graduate School

Committee:

Not Provided (Other)

Subjects:

Geophysics

Keywords:

Benthos;Sediment transport

Dewart, GilbertSeismic investigation of ice properties and bedrock topography at the confluence of two glaciers, Kaskawulsh Glacier, Yukon Territory, Canada /
Doctor of Philosophy, The Ohio State University, 1968, Graduate School

Committee:

Not Provided (Other)

Subjects:

Geophysics

Keywords:

Glaciers;Glaciology;Ice;Kaskawulsh Glacier ;Seismology

Cronk, CasparGlaciological investigations near the ice sheet margin, Wilkes Station, Antarctica /
Doctor of Philosophy, The Ohio State University, 1968, Graduate School

Committee:

Not Provided (Other)

Subjects:

Geophysics

Keywords:

Ice

Maike, Christopher AA Flood-Tidal Delta Complex, The Holocene/Pleistocene Boundary, and Seismic Stratigraphy in the Quaternary Section off the Southern Assateague Island Coast, Virginia, USA
Master of Science, University of Toledo, 2014, College of Natural Sciences and Mathematics
The Atlantic inner-shelf off the coast of Assateague Island preserves a complex stratigraphy in the Quaternary Section. Holocene highstands have been transgressing the island, yielding the current state. Seismic Reflection data off the Assateague Island coast reveal flood-tidal delta facies, tidal inlet channels, tidal creeks, and Holocene sand sheets. These facies indicate a former back-barrier environment off the Assateague Island coast, revealing a former offshore position of Assateague Island. The defining characteristic of the back-barrier environment is a flood-tidal delta complex approximately 4.5 km by 3.5 km. An isopach map of the flood-tidal delta reveals a ramp and facies thinning away from the ramp. Two main reflections are interpreted to be shoreface ravinements in the study area, which are time-transgressive subaqueous erosional surfaces produced during the landward movement of the transgressive systems tract. A third reflection is interpreted to be the pre-transgressive surface, marking the Holocene/Pleistocene Boundary. The depth of the pre-transgressive surface was interpreted throughout the entire study area. It resulted in a clean surface with a channel-like depression near seismic line 18. This depression is interpreted as being part of a lowstand drainage system.

Committee:

David Krantz (Advisor); Richard Becker (Committee Member); Alison Spongberg (Committee Member)

Subjects:

Geology; Geophysics

Keywords:

geology coastal stratigraphy maryland assateague holocene pleistocene

Kabbes, Jason E.Diamond Formation under Lower Mantle Redox Conditions: Experimental Constraints on the Mineralogical Host of Carbon in Earth’s Mantle
Master of Science, The Ohio State University, 2010, Geological Sciences

The oxidation state of the Earth is an area of great interest in petrology and mineral physics, as it plays a key role in governing mantle mineralogy and determining mineralogical host of elements with multiple valence states, such as iron and carbon. The amount of oxygen available to drive reactions in a system, as measured by oxygen fugacity, dictates a system’s mineralogy, as controlled by reactions with oxygen, including the oxidation of iron to form wüstite: Fe + 1/2O2 = FeO (iron wüstite buffer, IW), or the simultaneous oxidation of iron and diamond to form siderite: Fe + C + 3/2O2 = FeCO3 (siderite diamond iron buffer, SDI). The degree of oxidation of the lower mantle has been the subject of recent interest, particularly in light of the recently reported crystal-chemically controlled, pressure-induced auto-oxidation-reduction reaction in iron (Frost et al., 2004) and debates on the oxidation state of carbon in the mantle (Brenker et al., 2007; McCammon et al., 2004). In that pressure-induced iron self-reduction is independent of oxygen fugacity, it is likely that the coexistence of metallic iron and wüstite buffers mantle redox state at or near IW, as well as determines whether the host of carbon is either diamond or a carbonate. Therefore, knowledge of the relationship between the buffer assemblage containing both reduced and oxidized carbon (SDI buffer) and that containing both reduced and oxidized iron (IW buffer) is critical to knowing the mineralogical host of carbon throughout the mantle as a function of redox state.

Thermodynamic modeling of iron, carbon, wüstite, and siderite suggests the IW buffer lies between 1.5 and 2.5 log units above the SDI buffer across the pressure and temperature range of Earth’s mantle, suggesting that FeCO3 (siderite) will reduce to diamond. This model is supported by high-pressure, high-temperature experiments carried out in the laser-heated diamond anvil cell from 21-62 GPa and 2100-2300K, with starting material: Fe metal, FeCO3, and FeO. Diamond was detected by x-ray diffraction and Raman spectroscopy, as well as STEM-EDX on a thin foil prepared by focused ion beam milling (FIB). These findings suggest that in the more reducing regions of a laterally and axially heterogeneous mantle, carbonates will be reduced to diamond and/or iron carbide(s), with the greatest reduction potential occurring just before the siderite spin transition. In the more oxidizing regions, such as those near subduction zones and below D”, carbonate will be the stable host of carbon. If carbon is a major light element of the core, it is likely that it would have to have been sequestered prior to the formation of the post-perovskite phase and the D” region.

Committee:

Wendy Panero (Committee Chair); Michael Barton (Committee Member); Yu-Ping Chin (Committee Member)

Subjects:

Geology; Geophysics

Keywords:

carbon; carbonate; diemond; mantle; oxygen fugacity; redox

Leftwich, Timothy E.Geopotential investigations of the crustal structure and evolution of Mars
Doctor of Philosophy, The Ohio State University, 2006, Geological Sciences
A fundamental question in martian geology is whether bolide impact(s) or mantle convection caused the hemispheric dichotomy. Cross-cutting and superposed crustal features interpreted from the MGS topography, magnetic observations, gravity anomalies, and crustal thickness estimates strongly favor the impact origin of the hemispheric dichotomy. Chryse is possibly the earliest giant basin-forming impact recorded in the martian crust. It was followed respectively by the Borealis, Utopia, Arcadia, Hellas, Isidis, and Argyre impacts, whereas the volcanic provinces of the Tharsis Rise and Elysium Planitia formed more recently. The long-lived martian volcanism and magmatism is consistent with substantial contributions of energy transmitted by strong shock and seismic waves from the giant impacts to the underlying mantle and their antipodal axes. Other possible major impacts occurred in the Tharsis province at Sinai-Solis Planum, Syria Planum, and Thaumasia Planum. The giant impacts are superposed on ancient magnetic crust that forms an important temporal marker on the early crustal development of Mars. The radial banding in these magnetic anomalies may suggest they were formed in the expanding plasma-ejecta cloud of a giant northern impact that compressed and amplified the early ambient martian core field and imbued the surface materials with strong magnetic remanence. Impacts predominantly excavated the northern lowlands and covered the southern highlands with ejecta. Subsequent impact gardening, volcanism, and weathering by wind and fluids produced the current martian surface.

Committee:

Ralph von Frese (Advisor)

Subjects:

Geophysics

Keywords:

Mars; gravity; magnetism; crust; tectonics; impacts

Wang, JianModeling Accelerating Trands of Displacement in Geodetic Time Series
Master of Science, The Ohio State University, 2010, Geological Sciences

Geodesists and geophysicists engaged in crustal motion geodesy monitor the position (or displacement) time series associated with thousands of GPS stations worldwide. These time series are useful for studying a wide range of geodynamic phenomena including plate motion, mountain building, the earthquake deformation cycle, postglacial rebound, and environmental loading.

Station coordinate time series are expressed in a spatial reference frame which is typically a global, earth-centered, earth-fixed (ECEF) reference frame. The motion of a station in a given reference frame can be referred to as the trajectory of that station. The great majority of station trajectory models in use within the geodetic community are linear models, which consist of three component or sub-models characterizing: (i) the trend of displacement over time, (ii) jumps or discontinuities in the time series, and (iii) annual oscillations.

In this thesis, we use a constant velocity model for most trends, but a polynomial function for trends with time-varying velocity, Heavyside function to implement jumps if and when jumps are required, and a truncated Fourier series, typically composed of just annual and semi-annual terms to compose our standard linear trajectory model. We first illustrate the use of a polynomial trend model with reference to a GPS station of our GNET project which is well known to have a time-varying velocity, particularly in the vertical component. We then consider an original problem: quantifying time-changes in the velocity of a station COYQ near Coyhaique in southern Chile from CAP project which manifests postseismic transient deformation in the aftermath of the great 1960 Chile earthquake.

We have shown that station trajectory models in which the secular trend of displacement can be represented as a polynomial function of time can be very useful for modeling GPS time series obtained in areas undergoing accelerating ice loss, and in areas undergoing postseismic transient deformation a decade or more after a great earthquake. Of course the great majority of GPS stations can be characterized perfectly adequately using a constant velocity trend model. But the areas in which this is not true are areas of considerable geodynamic interest. This thesis presents a new tool for studying those areas.

Committee:

Michael Bevis, PhD (Advisor); C.K. Shum, PhD (Committee Member); Michael Barton, PhD (Committee Member)

Subjects:

Geophysics

Keywords:

GPS; time series; Geodetic; accelerating trend; trajectory model; GNET; CAP

Brandeberry, Jessica L.A Passive Seismic Investigation of the Crustal Structure under Ohio
Master of Science, University of Toledo, 2007, College of Arts and Sciences
Although gravity and magnetic field data have been used to infer variations in the crustal structure of Ohio, seismic evidence regarding the depth to the Mohoroviĉic discontinuity is sparse. First arrivals from 13 regional earthquakes recorded by the Ohio Seismic Network between 2001 and 2006 were examined to investigate variations in crustal composition and thickness in Ohio and attempt to calculate the depth to the mantle. The average crustal structure consists of two layers: Paleozoic sedimentary rock over granitic crust (phase Pg) overlying the mantle (phase Pn). The average apparent P-wave velocities for the Paleozoic sedimentary rock and granitic crust are 4.8 km/s and 5.5 km/s respectively. Reduced travel time curves of first arrivals show nodirect evidence of a higher (~ 6.8 km/s) velocity lower crust (crustal phase Pb). Paleozoic sedimentary rock thickness, determined from well data, ranges from 700 m in western Ohio to over 4 km in southeastern Ohio. Calculated thicknesses of the Paleozoic sedimentary rock (-5.8 ± 8.8 km in western Ohio, 26.9 ± 25.8 km in southeastern Ohio) and granitic crust (20.1 ± 10.1 km in western Ohio, 57.6 ± 29.6 km in southeastern Ohio) beneath each station, determined from regional earthquake residuals (1.8 ±1.8 seconds early in western Ohio, 5.0 ± 5.4 seconds late in southeastern Ohio), have a mean value higher than thicknesses derived from well data and gravity and magnetic field interpretations. However, these results involve large standard deviations that span crustal models previously proposed. Comparing these thicknesses determined from regional earthquakes with thicknesses determined from teleseismic earthquakes and Earthscope Automated Receiver Survey (EARS) seismic data show small variations beneath most stations. Those stations with large variations between regionally, teleseismically, and EARS determined thicknesses also have a small number of regional earthquake observations.

Committee:

Donald Stierman (Advisor)

Subjects:

Geology; Geophysics

Keywords:

Seismic refraction; crustal structure; Ohio; Mohorovi&265;ic discontinuity

Blake, Daniel R.Surface layer thickness and velocity determined using the Multi Channel Analysis of Surface Waves (MASW) method compared with microtremor resonance analysis-Federal Road, Greene County, Ohio
Master of Science (MS), Wright State University, 2012, Earth and Environmental Sciences
Multi-Channel Analysis of Surface Waves (MASW) was performed on data collected at four locations previously occupied by 3-component broadband seismometers. The goal was to use MASW to define the velocity structure and depth to bedrock locally, and to examine how well the calculated surface layer resonance derived from this velocity structure compares with the surface layer resonance observed in the passive seismic data at that site. At the test site east of Xenia, Ohio, a clear change in lithology (glacial drift to limestone bedrock) on each of the 1-D MASW profiles is indicated by a substantial change in shear-wave velocity (Vs) at depth and is consistent with the depth to bedrock from water wells in the area. Both water wells and the MASW results indicate that depth to bedrock increases significantly to the east along Federal Rd toward a pre-glacial buried valley. The calculated resonant frequency of the glacial drift surface layer, using the fundamental mode equation, compares very well to the peak frequency expressed in the horizontal to vertical ratio (H/V) of passive seismometer data at the same locations. A clear and distinct surface layer resonance is evident in most passive seismic data of this study, although one seismometer station expressed a double peak suggesting very local distinct variations in drift thickness such as expected at a bedrock ledge or a buried ravine or small valley. One practical conclusion of this study is that in settings of high velocity contrast between a surface layer and bedrock, where glacial drift overlies limestone bedrock, by determining the Vs of the drift using MASW, one can use the H/V peak frequency of 3-component seismic data to calculate the regional depth to bedrock values in locations where Vs is consistent.

Committee:

Ernest Hauser, PhD (Advisor); Doyle Watts, PhD (Committee Member); David Dominic, PhD (Committee Member)

Subjects:

Geophysics

Groshong, Kimberly AnnModeling the Effect of Calcium Concentration and Volumetric Flow Rate Changes on the Growth of Rimstone Dam Formations Due to Calcium Carbonate Precipitation
Master of Science, University of Akron, 2008, Applied Mathematics
Rimstone dams, formed in cave environments and composed primarily of calcium carbonate, are constructed through both chemical and mechanical processes. As calcium rich water flows over a sloped limestone cave floor, calcium carbonate precipitates from the solution. Standard fluid mechanics equations govern the hydrodynamics. Chemical kinetics describe movement through the boundaries and explain the bulk and surface reactions that influence precipitation. The free boundaries, gas-fluid and solid-fluid interfaces, couple the hydrodynamic and reactive transport equations. The chemical kinetics of bulk and surface reactions that result in precipitation are determined. This research focuses on the effect of changing the volumetric flow rate and altering the concentrations of calcium on the growth of the mineral-fluid boundary by developing and solving, through thin-film fluid flow approximations, appropriate hydrodynamic and reactive transport equations. Three general volumetric flow conditions are explored in this paper. The effect of slow, moderate, and fast flow rates under conditions of constant flow; exponentially decreasing flow, modeling drought conditions; and seasonal flow fluctuations about a base rate are investigated. The greatest growth was observed during seasonal fluctuations with a moderate volumetric flow rate. Greatest deposition, near the initial position, was with high concentrations of calcium flowing with a fast flow rate. Further downstream, the largest growth required small concentrations of calcium, which maintained a high pH condition in the system. From the developed equation for the mineral boundary, growth was affected by pH conditions driven from bulk reactions and influenced by degassing of carbon dioxide and surface reactions from the alterations in calcium concentration, ultimately driving the system pH.

Committee:

Gerald Young (Advisor); Curtis Clemons (Advisor)

Subjects:

Geochemistry; Geology; Geophysics; Mathematics

Keywords:

Rimstone Dams; calcium precipitation; cave formations;asymptotic expansion;volumetric flow rate;coupled differential equations

Atef, Ali HadiANALYSES OF URSEIS MOHO REFLECTIONS BENEATH THE PREURALIAN FOREDEEP OF THE URAL MOUNTAINS, RUSSIA
Master of Science, University of Akron, 2007, Geology-Geophysics
Reprocessing of the western-most portion of the Urals Seismic Experiment and Integrated Studies (URSEIS) survey across the southern Urals in Russia provided enhanced images of the crust and crust-mantle boundary (Moho). Shallow (less than 6 km deep), continuous subhorizontal reflections were associated with the base of the foreland basin. Those reflections appeared to shallow to the east. The middle and lower crust were generally reflective across the study area. The crust-mantle boundary (Moho) was imaged as high amplitude, continuous, subhorizontal reflections across the entire profile in the stacked section. The Moho reflections were dominated by low frequency arrivals that appeared as single and multi-cycle wavelets. Amplitude, frequency content and velocity analyses of those Moho reflections revealed that the Moho varied laterally on the kilometer-scale and vertically at the 100-meter scale. Power spectrum analyses appeared to indicate that the Moho represented a change from granulite to eclogite in a layer located at 43.8 km depth that varied in thickness from 125-200 m. Other reflections observed below Moho depths were determined to be crustal shear wave reflections based on their low stacking velocities.

Committee:

David Steer (Advisor)

Subjects:

Geology; Geophysics

Keywords:

Amplitude Versus Offset (AVO); Frequency Versus Offset (FVO); Amplitude Versus Shot Point (AVSP); Frequency versus Shot Point (FVSP); Model of Moho boundary; Frequency-Wave number analyses

Treiber, Katie MDeepwater Channel Systems in the Orca and Choctaw Basins, Northern Gulf of Mexico
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

Keywords:

Seismic interpretation; Turbidite channels; Deepwater channels; Orca Basin; Choctaw Basin; geomorphology; Gulf of Mexico; Salt-withdrawal mini-basins

Millard, Joseph WilliamPressure Dependence Of The Strength Of Magnesite Deforming By Low Temperature Plasticity, Diffusion Creep, Or Dislocation Creep
Master of Science, University of Akron, 2018, Geology
Recent experiments by Holyoke et al. [2014] indicate that magnesite is weak compared to olivine possibly, leading to strain localization into magnesite-bearing horizons of downgoing subducting slabs, and causing intermediate depth (200 – 400 km) deep focus earthquakes (DFE). However, they did not determine the pressure dependence of the strength of magnesite. In order to determine the pressure dependence of magnesite deforming by low temperature plasticity (LTP) mechanisms (kinking and dislocation glide), diffusion creep, and dislocation creep, I deformed two natural magnesite aggregates (d ~ 3 and 80 µm) over a wide range of pressures (Peff = 0.76 – 7.5 GPa) at strain-rates of ~ 10-5/s and at temperatures T = 500, 750, and 900 °C, respectively. Triaxial deformation experiments were conducted in the D-DIA at Beamline 6-BMB at the Advanced Photon source at Argonne National Lab and in the Griggs apparatus at the University of Akron. Differential stresses in all sets of experiments increase with increasing pressure. Microstructures in experiments performed on fine-grained magnesite at 500 °C include flattened, angular grains, which were slightly reduced in size; microstructures in experiments performed on fine-grained magnesite at 750 °C include rounded grains, increased porosity and four-grain junctions; and microstructures in experiments performed on coarse-grained magnesite at 900 °C include elongated grains, patchy undulatory extinction, and recrystallized grains at grain boundaries. Based on these results and results obtained by Holyoke et al. [2014], the pressure dependence or activation volume, (V*) = 33.8 (±1), 2.2 (±0.7), and 10.3 (±2)*10-6 m3/mol, for LTP, diffusion creep, and dislocation creep, respectively. With the addition of the influence of pressure to the flow laws of Holyoke et al. [2014], the strength contrast between magnesite and olivine decreases. However, magnesite remains orders of magnitude weaker than olivine at all subduction zone depths which may lead to strain localization and generation of DFE.

Committee:

Caleb Holyoke, Dr. (Advisor); John Peck, Dr. (Committee Member); James Thomka, Dr. (Committee Member)

Subjects:

Geology; Geophysics; Mechanics; Mineralogy

Keywords:

magnesite; diffusion creep; dislocation creep; low temperature plasticity; pressure dependence; deep-focus earthquakes; deformation mechanisms; rheology

Vasko, Erik S.Power Scaling of the Mainland Shoreline of the Contiguous United States
Master of Science (MS), Wright State University, 2018, Earth and Environmental Sciences
Previous fractal analyses of shoreline roughness have measured the fractal dimension of long segments of shoreline, e.g. Mandelbrot (1983) quantified the shoreline of the west coast of Britain and Feder (1988) quantified the shoreline of Norway. Consequently, changes in roughness along short segments are not captured by the analysis. In this study, the fractal dimension of the mainland shoreline of the contiguous United States has been measured in 125, 250, and 375 km segments using the box-counting method. The box counting method is based on the equation N = c x b where N is number of occupied boxes, C is a constant, x is box side length, and b is the fractal dimension (scaling exponent). A MATLAB code was written to measure the fractal dimension using the box-counting method. The fractal dimension measures the scaling property of a pattern not at any one length but over a range of lengths. In this study, the box-counting method counts occupied boxes over a range of box sizes along a segment of shoreline to measure the fractal dimension as it changes at different scales along the shoreline. The result is that the fractal dimension of the shoreline will continue to change as the segment length decreases. Thus, the single value of the fractal dimension reported by Richardson (1961) and Mandelbrot (1983) for the shoreline of the west coast of Britain or by Feder (1988) for the shoreline of Norway are each an approximation of the average fractal dimensions at smaller segment lengths. The shoreline analyzed in this study is the NOAA Medium Resolution Shoreline. Source map scales range from 1:10,000 to 1:600,000 with an average of 1:70,000. In the current study, sequentially numbered X-Y coordinate points in UTM Zone 18N, spaced 50 meters apart, as measured continuously along the shoreline comprised the shoreline. Fractal scaling was found on every section of the contiguous United States shoreline for each segment length (125, 250, 375 km) sampled. The range of fractal dimensions is 1.0 - 1.5. Fractal dimensions from 1.1 to 1.4 are consistently found in bays and rias. River banks have fractal dimensions ranging between 1.0-1.2, and never higher. Long stretches of smooth shoreline outside of bays that face towards open water have consistently low fractal dimensions of 1.0 to 1.1. Shorelines that double back on themselves, such as those of the Chesapeake Bay and Seattle Bay, Washington, have high fractal dimensions of 1.3 to 1.4. Low fractal dimensions were found along the Pacific shoreline, which is an emergent shoreline on a tectonically active plate margin. Low fractal dimensions are consistently measured on the Great Lakes shorelines. The high fractal dimensions observed along the Atlantic and Gulf shorelines may in part be due to high storm activity and the annual hurricane season. The Atlantic and Gulf of Mexico shorelines are both on tectonically passive margins.

Committee:

Chris Barton, Ph.D. (Committee Chair); Sarah Tebbens, Ph.D. (Committee Member); Mateen Rizki, Ph.D. (Committee Member)

Subjects:

Earth; Geology; Geophysics

Keywords:

fractal dimension; shoreline; US; MATLAB; Gulf of Mexico; Atlantic; Pacific; Great Lakes; scaling exponent

Hall, Tricia LPaleogene-Neogene seismic stratigraphy of McMurdo Sound, Antarctica: tectonic and climate controls on erosion, sediment delivery and preservation
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. Up until the Middle Miocene, variable climate and ice sheet conditions dictated the basal thermal regime of ice sheets. To test the view that cold based ice sheets in arid, polar deserts minimally erode the landscape, sediment volumes and mass accumulation rates were calculated for critical climatic intervals. From ~22 Ma to ~13 Ma the overall trend of mass accumulation rates declined, with a noticeable decline following the onset of cold-based glaciation during a global cooling trend following the Mid Miocene Climate Optimum ~15 Ma.

Committee:

Terry Wilson (Advisor); Lawrence Krissek (Committee Member); Derek Sawyer (Committee Member)

Subjects:

Geological; Geology; Geophysical; Geophysics

Keywords:

McMurdo Sound; Ross Sea; seismic stratigraphy; seismic facies; seismic reflection; geophysics; AND-2A core; mass accumulation rates; cold-based glaciation; Miocene; isopach; West Antarctic Rift System; Terror Rift

Nassar, Elias M.Numerical and experimental studies of electromagnetic scattering from sea ice/
Doctor of Philosophy, The Ohio State University, 1997, Graduate School

Committee:

Not Provided (Other)

Subjects:

Geophysics

Kong, Consuelo MargaritaDiscrete element analysis of powder processing : fill and compaction /
Doctor of Philosophy, The Ohio State University, 2000, Graduate School

Committee:

Not Provided (Other)

Subjects:

Geophysics

Weissman, SimhaHorizon-controlled analytical strip triangulation /
Doctor of Philosophy, The Ohio State University, 1967, Graduate School

Committee:

Not Provided (Other)

Subjects:

Geophysics

Keywords:

Photogrammetry

Radzevicius, Stanley JudeDipole antenna properties and their effects on ground penetrating radar data /
Doctor of Philosophy, The Ohio State University, 2001, Graduate School

Committee:

Not Provided (Other)

Subjects:

Geophysics

Gonsiewski, James P.Bedrock Mapping Using Shear Wave Velocity Characterization and H/V Analysis
Master of Science (MS), Wright State University, 2015, Earth and Environmental Sciences
An experiment was conducted to constrain the HVSR (Horizontal to Vertical Spectral Ratio) or H/V spectral ratio method at a glaciated site in northeast Ohio. Multiple methods were used to determine the shear wave velocity (Vs) and depth (h) to bedrock in relation to the fundamental resonant frequency (fo) determined from 3-component seismic data, as defined by the relationship f0=Vs/4h. The shear wave velocity structure was determined at three sites using MASW (Multi-channel Analysis of Surface Waves) and shear wave refraction methods, and the fundamental resonant frequency was passively observed using 3-component Guralp broadband seismometers. The Vs and bedrock depth results from both refraction and MASW produced comparable calculated theoretical f0 to that observed by the 3-component broadband seismometers. However, the bedrock depth and glacial drift Vs results were consistently lower for refraction than for MASW. Part of the calculations used with the generalized reciprocal method (GRM) method could yield bedrock depths that are underestimated proportionally with the Vs. Notably, the MASW results appear to be improved by combining overtones of multiple source offsets. The average Vs from the MASW and refraction surveys of this study were each used to calculate bedrock depth using the f0 observed for a suite of 73 seismometers previously deployed across the surrounding area as part of another study. Maps of these calculated bedrock depths correlate with the major dipping trends indicated by the water and gas wells in the area. At the site where the closest comparison could be made, the MASW determined Vs yielded a depth to bedrock that was significantly closer to the measured bedrock depth than the refraction determined Vs. This study suggests that an average shear wave velocity for glacial drift determined from a few MASW surveys in a region is sufficient to determine a viable average Vs to convert an array of 3-component f0 observations to produce a map of bedrock topography.

Committee:

Ernest Hauser, Ph.D. (Advisor); Doyle Watts, Ph.D. (Committee Member); David Dominic, Ph.D. (Committee Member)

Subjects:

Geophysical; Geophysics

Keywords:

MASW; shear wave refraction; HVSR; bedrock mapping; fundamental resonance; shear wave velocity; geophysics; seismology

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