Physical Sciences and Mathematics Commons^™

Application Of Hydrogeophysical Imaging In The Reynolds Creek Critical Zone Observatory, Travis Nielson

Boise State University Theses and Dissertations

The critical zone is defined as the upper most portion of the crust extending from the top of unweathered bedrock to the top of the vegetation canopy. It is the zone in which inorganic rock is transformed into biologically useful soils and saprolites in a process termed weathering. Because the critical zone is the connection between the subsurface and surface it plays a role in a wide variety of biological, hydrologic, and climatic processes. Understanding the critical zone though is inherently difficult because its scale and heterogeneity often means direct sampling methods, e.g. soil pits and cores, under represent the …

A Geophysical Investigation Of Stratigraphy And Structure On St. Catherines Island, Georgia, Anne M. Delua

Honors College Theses

Geophysical tools were used to investigate potential structural and stratigraphic pathways of the salt water intrusion that is affecting the surficial aquifer on St. Catherines Island, Georgia. Ground penetrating radar (GPR) is a geophysical tool that uses electromagnetic waves to view the subsurface. GPR is used for a variety of applications stratigraphically, biologically, and anthropogenically. GPR electromagnetic waves react to changes in density and composition and type and percentage of pore fluids in sediment and rock. GPR waves also react to interfaces including fractures and faults. GPR waves exhibit attenuation and decreased return signal in materials such as clay. Fresh …

Geophysical Study Of Complex Meteorite Impact Structures, William Zylberman

Electronic Thesis and Dissertation Repository

Hypervelocity impact craters are the most abundant morphologic features on rocky planetary bodies of the Solar System, except on Earth where they have mostly been erased by plate tectonics, erosion, or are buried under sediments. The internal structure of complex impact craters can only be studied on Earth by using ground-truth geophysical and geological studies. Such approaches - combined with modeling - can reveal how impact cratering, target geological composition, erosion and other post-impact processes can lead to the observed geophysical anomalies, which could also be detected by remote geophysical data on other planetary surfaces. In this work, a multidisciplinary …

How Dredge Pits Evolve Over Time: A Look At Their Geomorphologic Evolution And Infilling Processes, Patrick Robichaux

LSU Master's Theses

As coastal environments become more susceptible to land loss through accelerating sea level rise and subsidence, new restoration methods harnessing borrowed sediment are more valuable than ever. Mud-capped dredge pits (MCDPs) are a relatively new source of restoration-quality sediment that has only recently been utilized for beach and barrier island restorations in Louisiana. Because MCDPs have been in use for less than two decades in only a handful sites, little is understood about their evolution over decadal timescales. To improve our understanding of MCDPs after they are dredged, we have conducted a suite of geophysical surveys including bathymetry, sidescan sonar, …

Laboratory Resistivity Measurements For Soil Characterization, Behdad Mofarraj Kouchaki

Graduate Theses and Dissertations

Field based electrical resistivity measurements, such as electrical resistivity tomography (ERT) and capacitively coupled resistivity (CCR), are geophysical methods that offer a non-destructive and rapid means to collect continuous data. As such, ERT and CCR are becoming increasingly popular tools for geotechnical engineers; however, it is challenging to derive geotechnical information such as soil type, density, and water content from the data. A laboratory geophysical investigation was carried out to gain a better understanding of the parameters that affect the electrical resistivity of soils and devise a relationship between resistivity and soil type or classification. In this study, a soil …

Geophysical Assessment Of Kinion Lake Dam, Tim Allen Moody

Graduate Theses and Dissertations

Geophysical methods including Capacitively-Coupled Resistivity (CCR), Electrical Resistivity Tomography/Imaging (ERT/ERI), Multichannel Analysis of Surface Waves (MASW) with Love and Rayleigh waves and a Full-Waveform Inversion (FWI) were performed on Kinion Lake Dam, an earth-filled embankment dam that has historically experienced significant seepage and internal erosion issues. Surveys were completed along the crest and downstream toe of the dam. Results from the surveys indicate that each method is capable of resolving the bedrock depth within 1-2 m of locations shown on previous drilling logs, though some discrepancies between the methods exist. A weathered bedrock layer is believed to have led to …

Earthquake Segment Boundaries And Tsunamigenic Faults Of The Kodiak Segment, Alaska-Aleutian Subduction Zone, Marlon D. Ramos

Boise State University Theses and Dissertations

The most recent megathrust earthquake to impact the Alaska subduction zone was the M9.2 Great Alaska earthquake of 1964. This multi-segment rupture spanned over 700 km of the plate boundary and engendered both local and trans-Pacific tsunamis. The Kodiak Islands region served as the southwestern limit to rupture. The nature of past megathrust segmentation for the Alaska subduction zone has been largely hypothesized through paleoseismological methods and the Kodiak region in particular has not received a comprehensive geophysical characterization of its inferred segment boundaries.

I analyze multiple geophysical datasets (e.g. seismic reflection, earthquake, potential fields) to understand the spatiotemporal relationships …

Near Surface Geophysics For Lithostratigraphic Interpretation At Pedro, Benton County, Arkansas, Matthew David Ruggeri

Graduate Theses and Dissertations

The roadcut on highway 412 near Pedro, Benton County, Arkansas (MArkUP site L15), has been of geological interest since its excavation in the 1980s. The roadcut is located within the Springfield Plateau and displays formations of Lower Mississippian age. The roadcut contains three mound-like features believed to be olistoliths. This thesis research work adds geophysical evidence to the geological exposure at the site. The purpose of this research is to answer the question of whether near surface seismic methods can be used to extend information at the Pedro outcrop below the ground surface. Specifically, can the top of the Middle …

Gravity And Passive Seismic Methods Used Jointly For Understanding The Subsurface In A Glaciated Terrain: Dowling And Maple Grove Quadrangles, Barry County, Michigan, Scott A. Feldpausch

Masters Theses

The Horizontal to Vertical Spectral Ratio (HVSR) passive, single sensor seismic technique has been used together with gravimetry to study the topography hidden below the glacial drift of two 7.5’ quadrangles in Barry Co., MI. 265 stations were observed with both instruments along roads at nominal spacings of about 0.4 to 0.8 km. Occasional water wells and oil wells with documented penetrations of the base of glacial were used to calibrate the local power law regression calibration. This was also compared with the statewide calibration curve previously established. Results are presented as maps of Simple Bouguer Anomaly, Residual Bouguer Anomaly, …

Searching For The Unmarked Henry Kinsey Family Graves At The Va Hospital Grounds In Dayton, Ohio, Using Magnetic, Electromagnetic, And Radar Methods, Andrew William Bergman

Browse all Theses and Dissertations

The Henry Kinsey family was among the first to settle in the Dayton, Ohio, region in the early 19th century. Henry, and his wife Eva, were buried near what is known as the deer keeper’s lodge, a small building where the deer keeper lived, on the modern-day Dayton Veterans Affairs hospital grounds. In the time since they have been buried, the location of their gravesites has been lost. The main purpose of this thesis is to locate and map their graves using multiple geophysical methods. A secondary purpose is to compare the effectiveness of each geophysical method. Three geophysical methods …

Constraining Boundaries And Extent Of The Charleston Uplift, Northeast New Madrid Seismic Zone, Using Shallow Seismic Reflection Methods, Clara Rose Rucker

Theses and Dissertations--Earth and Environmental Sciences

A recently identified 30 km by 7.2 km subsurface stratigraphic uplift, called the Charleston uplift, exhibits 36 m offset of Paleogene-Quaternary unconformity based on shallow borehole data. Two seismic soundings demonstrated relief in Paleozoic and Cretaceous reflectors across the northern boundary of the uplift, suggesting a structural origin rather than an erosional origin. This study collected and analyzed 18 additional shallow seismic soundings to confirm Paleozoic and Cretaceous offset across the boundaries of the uplift, to better constrain the surface trace of the uplift, and to examine potential extension into western Kentucky. One ground penetrating radar profile was taken in …

Spatial Variability Of The Depth To The Magma Reservoir Beneath The Yellowstone Caldera Inferred From Observations Of Seiche Loading Induced Strain, Kevin James Gryger

LSU Master's Theses

Seiche waves in Yellowstone Lake at ~78, ~51, and ~25 minute periods and heights <10 cm can cause measurable strain (< 40 ns) as observed on borehole strainmeters both near (<300 m) and far (~20 km) from the lake. Observations of the correlation between the seiche waves and the associated strain response can be used to constrain the rigidity of the upper crust, the depth to magma bodies in the subsurface, and the viscosity (related to melt percentage) of the magma bodies in place. Lake level was directly measured with campaign absolute pressure gauges deployed in the West Thumb basin, Breeze Channel, and central basin of Yellowstone Lake, and 13 large seiche events (¡Ý7 cm) were identified from these observations. Periodic strain transients were measured on borehole strainmeters in the caldera during the 13 large seiche events. The peak-to-trough amplitude and phase of the seiche wave and strain response were estimated by fitting a multi-frequency sinusoid to the time series over a 4-hour window during each seiche event. It was found that the relationship between an applied seiche load and the associated strain response is self-consistent and linearly proportional at each borehole strainmeter in the caldera. Over multiple seiche events the observed strain response is consistent with a modeled strain-field produced by a seiche load on a two-layered viscoelastic model defined by free parameters Young¡¯s modulus (E1), plate thickness (H), and shear modulus ratio (¦Ì2/¦Ì1). The two-layered viscoelastic model represents a solid upper crust overlying a partially molten body which may be small pockets of melt (<1 km thickness) or a larger magma reservoir. Results suggest crystallizing melt beneath Yellowstone caldera at depths (H) of ~4¨C8 km in the south-southeast and ~3-5 km in the north-northwest sections of the caldera. Temporal observations between strain meters, coupled with constraints of Young¡¯s and shear moduli suggest that melt in the shallow crust has a viscosity ¡Ü1013 Pa s.

Pre-Mt. Simon Seismic Sequences Below West-Central Indiana: Local Interpretation And Regional Significance, Andrew Michael Parent

Browse all Theses and Dissertations

Constraining the composition, structure, and origin of basement provinces, deep assemblages of Precambrian rocks, is largely dependent on deep boreholes and geophysical techniques. This is especially true for the eastern U.S. midcontinent. Here, I employ regional 2-D seismic reflection, Bouguer gravity, and aeromagnetic data to interpret the upper crust below west-central Indiana. Seismic reflection data were donated to Wright State University in 2015. Geopotential data are available through the USGS and affiliates. These geophysical data, together, are analyzed in a regional geologic context. Three distinct seismic stratigraphic sequences are observed on 2-D sections. The first, uppermost sequence, typified by continuous, …

Potential Field Modeling Across The Neodymium Line Defining The Paleoproterozoic-Mesoproterozoic Boundary Of The Southeastern Margin Of Laurentia, Rachel Lauren Durham

Theses and Dissertations--Earth and Environmental Sciences

A zone of high magnetization along the SE margin of Paleoproterozoic Laurentia in the United States is indicated by magnetic anomaly data. The SE edge corresponds to the geochemical Neodymium mantle derivation model age (T_DM) boundary and the entire anomaly overlies the Paleoproterozoic Mazatzal Province. Two-dimensional gravity and magnetic models across the Nd boundary are created with Moho constrained from receiver functions with gravity, sedimentary thickness and the base of the crustal magnetization. Upper crustal magnetization does not show strong variation across this boundary and much of the strong magnetization appears to lie in the middle crust. Using …