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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

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

Ahammod, ShamimDetermination of Vp, Vs, Glacial Drift Thickness and Poisson’s Ratio at a Site in Jay County, Indiana, Using Seismic Refraction and Multichannel Analysis of Surface Wave (MASW) Analysis on a Common Data Set
Master of Science (MS), Wright State University, 2015, Earth and Environmental Sciences
In July 2013, an industry-scale seismic reflection survey was conducted at a site in northern Jay County, Indiana, by geophysics students and faculty of Wright State University. As a part of that effort, a separate near-surface seismic dataset was collected to examine the Vp, Vs, and Poisson’s Ratio of the glacial drift and upper bedrock. This near-surface study successfully used a common dataset that was separately analyzed for both Vp (seismic refraction) and Vs (MASW) to calculate the Poisson’s Ratio of the glacial drift and underlying bedrock. The driller’s log for a water well near the east end of this near-surface survey indicates glacial drift (unconsolidated clay and sand) overlies limestone bedrock at a depth of 110 feet. Water wells in the broader area show bedrock depth varying from 110 to 122 feet, but locally as much as 140 feet. The near-surface seismic data were acquired using a Bison EWG (Elastic Wave Generator) assisted weight drop source that shot every station through a stationary spread of 48 channels using a pair of 24-channel Geode seismographs. Each channel recorded a a single vertical 4.5 Hz geophone at a station spacing of 10 feet. Four weight drop records at each source point were summed to enhance the S/N ratio. The same data volume was processed both for Vs using SurfSeis3 MASW (Multichannel Analysis of Surface Wave) software and for Vp using IXRefrax3 refraction software. The MASW results suggest that the depth to bedrock at the survey location ranges from 115-120 feet (~35 m) with Vs of 1,200-2,000 ft/sec (366-610 m/s) for glacial drift and 2,400-2,700 ft/sec (730-823 m/s) for bedrock. The P-wave refraction results suggest the depth to bedrock ranges from 118-122 feet (36-37 m) with average Vp of ~5,000 ft/sec (1,524 m/s) for glacial drift and ~17,000 ft/sec (5180 m/s) for limestone bedrock. The Poisson’s Ratio for the glacial drift calculated using the Vp and Vs at common locations in this study is 0.470-0.473, which is consistent with published results elsewhere. This study suggests that Poisson’s ratio can be determined using velocities from different analysis methods on the same dataset with good results.

Committee:

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

Subjects:

Energy; Geophysical; Geophysics

Keywords:

Seismic Reflection Survey; Seismic Refraction; Multichannel Analysis of Surface Wave Analysis; Poissons Ratio; Drillers Log; Geode Seismographs; Geophone; Elastic Wave Generator

Wan, JunkunJoint Estimation of Vertical Land Motion and Global Sea-Level Rise over the Past Six Decades Using Satellite Altimetry and Tide Gauge Records
Doctor of Philosophy, The Ohio State University, 2015, Geodetic Science and Surveying
Determination of the 20th and early 21st century sea level rise and understanding the geophysical causes leading to sea level rise is a significant scientific topic. Satellite radar altimeter has been providing continuous and near-global sea level measurements since 1992. Despite of the fact that multiple satellite altimeter measurements have reached a 23-year data record, it is still too short to isolate the definitive sea level rise signal from the contamination of interannual or longer oceanic variability. In contrast, global tide gauges measure the relative sea level and have data records as long as 200 years, but the measurements are susceptive to or contaminated by the vertical motion of the solid Earth. Despite the availability of geophysical models or collocated GPS stations at the tide gauge benchmarks, the separation of vertical land motions from long-term sea level signal in tide gauge records remains to be a challenge to be practically applicable to improve sea level rise projections. To improve the accuracy of altimeter estimated geocentric sea level over the last 23 years, we process altimeter data from different satellite missions. Least-squares collocation technique has been applied in the generation of multi-satellite altimeter gridded data products, 1992–2015, with updated estimates of reference frame offsets. Furthermore, we improved the sea level data record quality, based on comparisons with available in situ tide gauges and increased data points, over seasonally sea-ice covered Arctic Ocean from our reprocessed ERS-1 and ERS-2 altimeter measurements. Finally, our composite altimeter data set yielded a global sea level trend estimate of 2.8±0.6 mm/yr, and the regional trend estimate of 2.3±1.3 mm/yr for the Arctic Ocean, 1992–2015, respectively. To improve vertical land motion estimates at world’s tide gauge locations for the improved recovery of sea level rise signal, we proposed a new method, based on adjustment algorithm and sea level reconstruction, to combine radar altimeter and tide gauge data. First, we validated our multi-satellite altimeter sea level are consistent with in situ sea level from the global tide gauge network. Results comparing 559 globally distributed tide gauges show that our multi-satellite sea level data has an average correlation with tide gauge sea level at 0.85±0.09, and standard deviation of difference of 4.4±1.6 cm. Application of regional adjustment algorithms results in globally selected 158 tide gauge vertical motion estimates with the difference of –0.19±1.67 mm/yr against independent GPS@Tide gauge vertical motion solutions. The result is a significant improvement over the priori vertical motion estimates with an average difference of –0.11±3.15 mm/yr against the independent GPS rates. Finally, we further improved the algorithm with an iterative procedure to separate the vertical motion at 417 world’s tide gauges and sea level rise, by combining altimetry and tide gauge data to simultaneously estimate vertical motion at the tide gauge locations, and to reconstruct the global sea level variations, 1950–2012. The resulting vertical motion solution yields a discrepancy at 0.01±1.67 mm/yr against 210 independent GPS rates, and an average rate of global sea level rise at 1.70 mm/yr.

Committee:

C.K. Shum (Advisor); Christopher Jekeli (Committee Member); Alan Saalfeld (Committee Member)

Subjects:

Earth; Geophysics

Wei, LiProcessing and Interpretation of Three-Component Borehole/Surface Seismic Data over Gabor Gas Storage Field
Master of Science (MS), Wright State University, 2015, Earth and Environmental Sciences
Analysis of a seismic dataset recorded as part of a collaborative project between Wright State University, Spectraseis, Precision Geophysical, and Dominion East Ohio over the Gabor gas storage field, Canton, Ohio, is the topic of this study. Two types of sources (vibroseis and small seismic shot-holes) as well as three types of recording systems (passive 3C broadband on the surface, experimental 3C borehole sondes, and conventional 2D surface geophone profiles) were employed with different purposes. The shot hole explosives were calibration check-shots for the 3C borehole array repeatedly deployed at multiple levels. The vibrators of the conventional 2D seismic profiles were also recorded with the borehole array, a series of 3C surface seismometers along the 2D seismic lines and a spiral array of 3C seismometers centered at the wellhead. Processed and migrated seismic data from the pair of 2D surface seismic lines crossing directly over the well location were provided by Tom McGovern of Seismic Earth Resources Technology. The particular aims of this project are to determine wave velocities from first breaks, to apply VSP processing procedures on the borehole data, and to analyze spectral attributes in the low frequency range from a beat-sweep test. This VSP study was attempted despite the fact that the data were not collected for that purpose, and unfortunately the analysis of the borehole data failed to show expected subsurface reflectors. The raw borehole records have many characteristics unique to the borehole environment, which include effects of poor geophone clamping, bad cementation and tube waves. A frequency filter combined with trace mutes was very effective in enhancing wanted events as well as improving wave shapes. Time shifts between successive traces were obtained through cross-correlation. The true wave velocities were determined based on a single layer model, and were compared to the stacking velocities obtained from surface-recorded seismic data. Several VSP processing procedures were applied attempting to track up-going reflections from the borehole records, including static time shifting, FK filtering, NMO correction, and trace stacking. The stacked VSP trace was tied to surface seismic section, however, showed poor correlation in terms of subsurface horizons. Data from a beat-sweep test was also analyzed with the hope of verifying a low frequency spectral anomaly over the gas field. During the beat sweep tests and for minutes afterward the phenomenon of distinctly increased amplitude at 3Hz was present in both surface and borehole measurements. This beat-sweep test survey provided a tantalizing first look at a way of generating low frequency seismic energy to examine the low frequency anomaly over hydrocarbon reservoirs, and in this case successfully verified the production of a 3Hz anomaly.

Committee:

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

Subjects:

Geophysics

Keywords:

borehole seismic, VSP, spectral attributes, low frequency anomaly

Zhu, KefengApplication of Satellite Remote Sensing on Mountain Glacier and Coastal Zone Classification And Monitoring in South Asia
Doctor of Philosophy, The Ohio State University, 2015, Geodetic Science and Surveying
Observations from Earth’s remote sensing satellites have been a promising tool for studies on land cover and its changes, and related environmental phenomena. In this study, we demonstrate two environmental related land cover classification applications using integrated methods that involve multiple passive and active remote sensing sensors onboard different satellites, including Landsat Thematic Mapper (TM) and other optical/infrared imageries, synthetic aperture radar (SAR) system such as the Phased Array type L-band Synthetic Aperture Radar (PALSAR) onboard of the Advanced Land Observing Satellite (ALOS), and radar altimeters such as the Environmental Satellite (ENVISAT), etc. Firstly, we did a case study in Geladandong glacier of classifying and obtaining the rock/glacier boundary using Landsat data as well as integrated SAR methods, including polarimetric SAR classification and repeat pass SAR correlation coefficients technique. Over 40 years, the shrinkage of the glacier was observed from the results of analyzing and classifying Landsat series data. The estimated retreating rates are 0.148 km2/year and 0.134 km2/year in region B and C of Geladandong glacier during 1973~2014. The Randolph Glacier Inventory (RGI) 4.0 does not provide this dynamic changing of the glacier extent. Moreover, considerable biases have also been observed in several regions. To further strengthen the finding, we employed SAR and polarimetric SAR data by applying correlation coefficient calculation and polarimetric SAR decomposition and segmentation. The results were consistent with those from Landsat classification in every particular small glacier region. Secondly, data from multiple satellite sensors, including Landsat series, ALOS-1 PALSAR Synthetic Aperture Radar and ENVISAT altimeter are employed for the purpose of analyzing the water extent in polder regions and its changing trend in last 40 years and of surveying the impact on polder embankments caused by erosion and sedimentation. In Polder 14, the surface elevation was approximately 30 centimeters higher in May than in August, given by ENVISAT surface elevation data. River channel boundary change in Arpangasia is also investigated. The river channel shape has been changed with approximately 1.4km2 on both sides of the river segment in the past 40 years. In the estuary region Polder 50~57, delta displacement in delta boundaries is observed in the water/land classification results based on Landsat data from 1972 and 2011. Moreover, the results from applying H/A/Alpha Wishart classification algorithm with full polarization SAR data provided more detailed surface types that can help monitoring and estimate the potential flooding risk of the region.

Committee:

C.K. Shum (Advisor); Alan Saalfeld (Committee Member); Michael Durand (Committee Member)

Subjects:

Climate Change; Environmental Science; Geography; Geophysics

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