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Full-Text Articles in Physical Sciences and Mathematics

Utilizing The Hvsr Second Peak For Surface Wave Inversions In The Mississippi Embayment, Ashraf Kamal Himel Dec 2018

Utilizing The Hvsr Second Peak For Surface Wave Inversions In The Mississippi Embayment, Ashraf Kamal Himel

Graduate Theses and Dissertations

Ambient noise data from 24 sites within the Mississippi Embayment were analyzed to estimate the fundamental frequency using the horizontal to vertical spectral ratio (HVSR) method. The fundamental frequency ranged from 0.17 to 3.43 Hz for the tested sites. At seventeen of the sites, a second higher frequency HVSR peak, which ranged from 0.617 Hz to 2.154 Hz, was observed in addition to the fundamental HVSR peak. The second peak frequency in the HVSR curve has been attributed by previous researchers as either an odd harmonic of the fundamental peak or a shallow impedance contrast from the Memphis sand layer …


Holocene Formation And Evolution Of Horn Island, Mississippi, Usa, Nina Gal Dec 2018

Holocene Formation And Evolution Of Horn Island, Mississippi, Usa, Nina Gal

Master's Theses

Horn Island, one of the most stable barriers along the Mississippi-Alabama chain, provides critical habitat, helps regulate estuarine conditions in the Mississippi Sound, and reduces wave energy and storm surge for the mainland. This study integrates 2,200 km of high-resolution geophysics, 35 sediment cores, and 15 radiocarbon ages to better understand the formation and evolution of the island in response to sea-level rise, storms, and antecedent geology. The Biloxi and Pascagoula incised valleys converge at Horn Island and have played a profound role in the evolution of the system. Within the incised valleys, numerous shallow paleochannels between 4 and 9 …


Groundwater Recharge Response To Reduced Irrigation Pumping In Western Nebraska, Justin Philip Gibson Nov 2018

Groundwater Recharge Response To Reduced Irrigation Pumping In Western Nebraska, Justin Philip Gibson

School of Natural Resources: Dissertations, Theses, and Student Research

Given current and continued investment in irrigation scheduling technologies, a need exists to better estimate the longevity and magnitude of water savings at watershed level to avoid the paradox of irrigation efficiency. This paradox occurs within a watershed as not all irrigation inefficiencies lead to the system losing water. For example, irrigation pumping rates in excess of crop water demand may lead to enhanced groundwater recharge or surface runoff that migrates to a stream. Thus, increases in efficiency may not lead to similar magnitudes of water savings. I hypothesize that water savings longevities are short given previous work demonstrating rapid …


Sh-Mode Seismic-Reflection Imaging Of Earthfill Dams, Edward W. Woolery Oct 2018

Sh-Mode Seismic-Reflection Imaging Of Earthfill Dams, Edward W. Woolery

Earth and Environmental Sciences Faculty Publications

Assessing subsurface characteristics and imaging geologic features (e.g., faults, cavities, low-velocity layers, etc.) are typical problems in near-surface geophysics. These questions often have adverse geotechnical engineering implications, and can be especially acute when associated with high-hazard structures such as large earthen flood-control dams. Dam-related issues are becoming more frequent in the United States, because a large part of this major infrastructure was designed and constructed in the early- to mid-twentieth century; these dams are thus passing into the latter stages of their design life, where minute flaws that were overlooked or thought to be insignificant in design/construction are now …


Integrated Geophysical Analysis In The Northeastern Gulf Of Mexico, Mei Liu Jul 2018

Integrated Geophysical Analysis In The Northeastern Gulf Of Mexico, Mei Liu

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

The formation of the Gulf of Mexico (GoM) relates to the breakup of Pangea and opening of the central Atlantic Ocean. The tectonic history of the basin is still being debated due to lack of geological constraints. This project addresses the crustal architecture in the northeastern GoM from integrative analysis of multiple geophysical datasets to provide constraints for the tectonic reconstruction.

The objectives of this study are: 1) to delineate various tectonic zones (continental and oceanic domains) and map the boundary between them, 2) to derive physical properties of the subsurface rocks, 3) to map the major tectonic structures in …


The Effect Of Microbial Growth On The Spectral Induced Polarization Response In Hanford Vadose Zone Sediment In The Presence Of Autunite, Alejandro Garcia Jun 2018

The Effect Of Microbial Growth On The Spectral Induced Polarization Response In Hanford Vadose Zone Sediment In The Presence Of Autunite, Alejandro Garcia

FIU Electronic Theses and Dissertations

Uranium contamination of the subsurface remains a significant problem at the Department of Energy Hanford site. A series of column experiments were conducted on Hanford sediment saturated with simulated groundwater to study the effects of aqueous bicarbonate and microbial growth on the mobility of Uranium. Spectral induced polarization (SIP) measurements in the columns were conducted concurrently with pore water sampling in order to monitor changes occurring inside the sediment after the initiation of microbial growth induced by glucose injection. The microbial growth caused significant increases in the real component of the complex conductivity and is the result of ion release …


Detection Of Bedrock Fractures And Joints Beneath Cover: Geophysical Approaches To An Engineering Geology Problem, Muthanna Yousif Yaqoob Aldiney Jun 2018

Detection Of Bedrock Fractures And Joints Beneath Cover: Geophysical Approaches To An Engineering Geology Problem, Muthanna Yousif Yaqoob Aldiney

Dissertations

This research used geophysical methods to detect the presence of sub-vertical failure planes, their direction(s), and their frequency in bedrock beneath soil or glacial drift overburden. Azimuthal measurements using the seismic, electrical resistivity (ER), and electromagnetic conductivity were made to evaluate which techniques might provide the best indication of the bedrock joints, faults, or shear zones. Measurements were made at multiple sites near each of three locations: Jackson, Alpena, and Grand Ledge, Michigan. The first two are former limestone quarries and the third is underlain by sandstone. Seismic measurements began with one or two linear refraction spreads, used to establish …


A Geophysical Delineation Of A Normal Fault Within The Gulf Coastal Plain, Montgomery County, Texas, Danielle Minteer May 2018

A Geophysical Delineation Of A Normal Fault Within The Gulf Coastal Plain, Montgomery County, Texas, Danielle Minteer

Electronic Theses and Dissertations

The Gulf Coast of Texas has been a known hydrocarbon basin for many years with various structural trapping mechanisms such as anticlines, faults and salt domes. While most large salt domes have been extensively studied in the Gulf Coastal Plain, many smaller normal faults have not been studied in detail. This research study employs an integrated geophysical approach to mapping the Big Barn fault in Montgomery County, Texas. This fault is located on the Gulf Coastal Plain and is approximately 20 miles north of Houston, Texas. Most normal faults in the Gulf Coastal Plain formed as a result of the …


Mapping Bedrock Topography Of The Portage And Schoolcraft Nw 7.5’ Quadrangles, Kalamazoo Co. Mi, Using The Hvsr Passive Seismic Method, Benjamin B. Seiderman Apr 2018

Mapping Bedrock Topography Of The Portage And Schoolcraft Nw 7.5’ Quadrangles, Kalamazoo Co. Mi, Using The Hvsr Passive Seismic Method, Benjamin B. Seiderman

Masters Theses

This study utilizes the Horizontal to Vertical Spectral Ratio (HVSR) technique to map bedrock topography in the Portage and Schoolcraft NW quadrangles, Kalamazoo Co., MI, looking for buried bedrock valleys. Glacial sediment-landform assemblages dominate the study area, due to multiple advances of the Laurentide Ice Sheet (LIS). Tunnel valleys, which are one type of buried valley, are eroded by subglacial meltwater and commonly filled with the coarser varieties of glacial outwash, making them potential aquifers. The HVSR technique measures the ratio of horizontal to vertical ground motion, excited by ambient seismic noise, resulting in a peak at the resonance frequency. …


Geologic Mapping Of The Bronson North And Bronson South 7.5-Minute Quadrangles, Branch County, Michigan, Karl John Backhaus Apr 2018

Geologic Mapping Of The Bronson North And Bronson South 7.5-Minute Quadrangles, Branch County, Michigan, Karl John Backhaus

Masters Theses

This study contributes to a better understanding of the glacial history of southwest Michigan through detailed surficial geologic and bedrock topography mapping within the Bronson North and Bronson South Quadrangles in Branch County, Michigan. This project was supported during the summer of 2017 by the USGS EDMAP program in conjunction with the Michigan Geological Survey. Hand-auger borings, grain size analysis tests, passive seismic depth-to-bedrock measurements, and ground penetrating radar transects were collected for this study. There are 350 feet of bedrock relief from west to east across the quadrangles, including a bedrock cuesta of Mississippian Coldwater Shale. This cuesta underlies …


Combining Hydraulic Head Analysis With Airborne Electromagnetics To Detect And Map Impermeable Aquifer Boundaries, Jesse T. Korus Jan 2018

Combining Hydraulic Head Analysis With Airborne Electromagnetics To Detect And Map Impermeable Aquifer Boundaries, Jesse T. Korus

Conservation and Survey Division

Impermeable aquifer boundaries affect the flow of groundwater, transport of contaminants, and the drawdown of water levels in response to pumping. Hydraulic methods can detect the presence of such boundaries, but these methods are not suited for mapping complex, 3D geological bodies. Airborne electromagnetic (AEM) methods produce 3D geophysical images of the subsurface at depths relevant to most groundwater investigations. Interpreting a geophysical model requires supporting information, and hydraulic heads offer the most direct means of assessing the hydrostratigraphic function of interpreted geological units. This paper presents three examples of combined hydraulic and AEM analysis of impermeable boundaries in glacial …