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Articles 61 - 90 of 123
Full-Text Articles in Geophysics and Seismology
Impacts Of Basin-Scale Climate Modes On Coastal Sea Level: A Review, Weiqing Han, Detlef Stammer, Philip Thompson, Tal Ezer, Hindu Palanisamy, Xuebin Zhang, Catia M. Domingues, Lei Zhang, Dongliang Yuan
Impacts Of Basin-Scale Climate Modes On Coastal Sea Level: A Review, Weiqing Han, Detlef Stammer, Philip Thompson, Tal Ezer, Hindu Palanisamy, Xuebin Zhang, Catia M. Domingues, Lei Zhang, Dongliang Yuan
CCPO Publications
Global sea level rise (SLR) associated with a warming climate exerts significant stress on coastal societies and low-lying island regions. The rates of coastal SLR observed in the past few decades, however, have large spatial and temporal differences from the global mean, which to a large part have been attributed to basin-scale climate modes. In this paper, we review our current state of knowledge about climate modes’ impacts on coastal sea level variability from interannual-to-multidecadal timescales. Relevant climate modes, their impacts and associated driving mechanisms through both remote and local processes are elaborated separately for the Pacific, Indian and Atlantic …
Use Of Seismic Refraction In Determining Rock Mass Anisotropy, Mohammad Najmush Sakib Oyan
Use Of Seismic Refraction In Determining Rock Mass Anisotropy, Mohammad Najmush Sakib Oyan
Electronic Theses and Dissertations
Seismic refraction is a popular method used by geological/geotechnical engineers to understand subsurface conditions. This method along with information collected from borings produce a realistic image of the ground beneath us. The goal of this study is to define and test a set of procedures to use seismic refraction alone to create high quality images of subsurface conditions. The focus is on areas with several meters of soil overlain by bedrock. The application of these procedures will minimize construction costs by eliminating the need for multiple boreholes. The results show that two important criteria must be met for successful application …
Integrated Seismic-Reflection And Microgravity Imaging Across The Southern Boundary Of The Charleston Uplift, New Madrid Seismic Zone, Usa, Drew D. Burford Jr.
Integrated Seismic-Reflection And Microgravity Imaging Across The Southern Boundary Of The Charleston Uplift, New Madrid Seismic Zone, Usa, Drew D. Burford Jr.
Theses and Dissertations--Earth and Environmental Sciences
The Charleston Uplift (CU), a 30-km-long by 7-km-wide, N46°E-oriented subsurface geologic anomaly in the northern Mississippi embayment near Charleston, Missouri, exhibits up to 36 m of vertical relief across the Paleogene/Quaternary unconformity. Subsurface structural relief, along with the CU’s coincident boundary alignment with contemporary microseismicity and the New Madrid North Fault (NMNF), suggest a structural origin. Subsequent seismic soundings indicate vertical structural relief is present in Cretaceous and Paleozoic horizons, supporting the fault-controlled origin. The southern boundary (CU-s) had not been investigated, nor had any direct fault images been acquired. Integrated microgravity and seismic-reflection methods across the inferred CU-s establish …
Electrical Conductivity And Resistivity Study Of Heterogeneous Sediment In Inwood Hill Park, Manhattan, Ny, Rea A. Khaleda
Electrical Conductivity And Resistivity Study Of Heterogeneous Sediment In Inwood Hill Park, Manhattan, Ny, Rea A. Khaleda
Dissertations and Theses
The area near the inlet of Spuyten Duyvil Creek in Inwood Hill Park in New York City exhibits complex hydrological processes. The inlet is a tidal flat, which contains brackish water; a mixture of saltwater and freshwater. The area was modified by man, built on a shell bed and contains heterogeneous sediment. One field adjacent to the inlet contains several small sinkholes. Electrical resistivity and ground conductivity techniques were used in order to get an understanding of the hydrological processes of this field. It was hypothesized that the formation of the sinkholes is due to the tidal forcing of the …
Archaeological Investigation Using Geophysical Methods To Locate Historic Byram's Ford Road, Marshall Seth Foster
Archaeological Investigation Using Geophysical Methods To Locate Historic Byram's Ford Road, Marshall Seth Foster
Masters Theses
"Ground penetrating radar, a time domain electromagnetic metal detector and a frequency domain electromagnetic metal detector were used with the goal of locating a section of the Byram's Ford Road believed to be intersecting the historic Big Blue Battlefield in the Westport area of Kansas City, Missouri.
Ground penetrating data were acquired at three sites, Site A, Site B, and Site C. The time domain EM metal detector was used to acquire data at Site A, where subsequent ground truthing was conducted using the frequency domain EM metal detector and an excavation tool. Significant anomalies were visible on both the …
Phosgene In The Upper Troposphere And Lower Stratosphere: A Marker For Product Gas Injection Due To Chlorine-Containing Very Short Lived Substances, Jeremy J. Harrison, Martyn P. Chipperfield, Ryan Hossaini, Christopher D. Boone, Sandip Dhomse, Wuhu Feng, Peter F. Bernath
Phosgene In The Upper Troposphere And Lower Stratosphere: A Marker For Product Gas Injection Due To Chlorine-Containing Very Short Lived Substances, Jeremy J. Harrison, Martyn P. Chipperfield, Ryan Hossaini, Christopher D. Boone, Sandip Dhomse, Wuhu Feng, Peter F. Bernath
Chemistry & Biochemistry Faculty Publications
Abstract: Phosgene in the atmosphere is produced via the degradation of carbon tetrachloride, methyl chloroform, and a number of chlorine‐containing very short lived substances (VSLS). These VSLS are not regulated by the Montreal Protocol even though they contribute to stratospheric ozone depletion. While observations of VSLS can quantify direct stratospheric source gas injection, observations of phosgene in the upper troposphere/lower stratosphere can be used as a marker of product gas injection of chlorine‐containing VSLS. In this work we report upper troposphere/lower stratosphere measurements of phosgene made by the ACE‐FTS (Atmospheric Chemistry Experiment Fourier Transform Spectrometer) instrument and compare with results …
Seismic Analysis Of The 30 July 1972 Sitka Earthquake Aftershocks, Stress Drop Of Aftershocks In Cook Strait, New Zealand Following The 2013 Cook Strait And Lake Grassmere And 2016 Kaikoura Earthquakes, And 2d Seismic Tomography In The Brady Hot Springs Geothermal Site, Nevada, Juan Alejandro Ochoa Chavez
Open Access Theses & Dissertations
The 1972 Mw 7.6 Sitka earthquake is the largest earthquake to have occurred along the Alaska portion of the Queen Charlotte fault (QCF) in historic time. The QCF system forms the plate boundary between the Pacific and North American plates within southeastern Alaska and has accumulated enough slip since 1972 to produce a comparable sized event in the near future. Thus, it is important to better understand the controls on the rupture process of the 1972 mainshock and its aftershocks. Following the mainshock the U.S. Geological Survey installed a network of 11 portable seismographs that recorded over 200 aftershocks of …
Probing Earth Deformation In Response To Localized Hydrologic Mass Loading, Susitna River Basin, Alaska, Andrew Parker Keene
Probing Earth Deformation In Response To Localized Hydrologic Mass Loading, Susitna River Basin, Alaska, Andrew Parker Keene
Graduate Student Theses, Dissertations, & Professional Papers
Surface mass loading contributes a ubiquitous signal to GPS time series that can be modeled and removed for individual sources. We utilize nine GPS stations in the Susitna River watershed, Alaska, to investigate surface displacements from surface mass loading. We find that modeling atmospheric surface pressure and regional hydrologic mass reduces root mean square (RMS) error by 27-39% for all GPS time series. We observe moderate correlation between residual time series pairs and distance, with elevation differences influencing the strength of this correlation. Seasonal horizontal and vertical displacements are observed after removal of all loading models; stations displace downward and …
A Machine-Aided Seismic Signal Analysis Workflow For Subsurface Faults And Facies Visualization And Interpretation, South Central Anadarko Basin, Oklahoma, Wade Martin
Graduate Theses, Dissertations, and Problem Reports (ETD)
Seismic attribute analysis enhances the understanding of subsurface geology and has continually gained traction in the oil and gas industry since the 1970’s. Many seismic attributes are available for petroleum geoscientists. This research intends to provide insight to an analytical attribute workflow for rock property estimation in the Anadarko basin of Oklahoma that is prolific in oil and gas exploration, with a particular focus on seismic texture. 3-D volumes processed for seismic texture facies and structure enhance geophysical investigation and interpretation of amplitude data. This study will contribute valuable insight to reservoir studies and the potential for texture attribute well …
Utilizing The Hvsr Second Peak For Surface Wave Inversions In The Mississippi Embayment, Ashraf Kamal Himel
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
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 …
Sh-Mode Seismic-Reflection Imaging Of Earthfill Dams, Edward W. Woolery
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
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 …
Detection Of Bedrock Fractures And Joints Beneath Cover: Geophysical Approaches To An Engineering Geology Problem, Muthanna Yousif Yaqoob Aldiney
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
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 …
Geologic Mapping Of The Bronson North And Bronson South 7.5-Minute Quadrangles, Branch County, Michigan, Karl John Backhaus
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 …
Mapping Bedrock Topography Of The Portage And Schoolcraft Nw 7.5’ Quadrangles, Kalamazoo Co. Mi, Using The Hvsr Passive Seismic Method, Benjamin B. Seiderman
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. …
Application Of Hydrogeophysical Imaging In The Reynolds Creek Critical Zone Observatory, Travis Nielson
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
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 …
How Dredge Pits Evolve Over Time: A Look At Their Geomorphologic Evolution And Infilling Processes, Patrick Robichaux
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
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
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
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
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 …
Integrated Approach For Sinkhole Evaluation And Evolution Prediction In The Central Ebro Basin (Ne Spain), Oscar Pueyo Anchuela, Andrés Pocoví Juan, Antonio M. Casas Sainz, Javier Gracia Abadias, Carlos L. Liesa Carrera
Integrated Approach For Sinkhole Evaluation And Evolution Prediction In The Central Ebro Basin (Ne Spain), Oscar Pueyo Anchuela, Andrés Pocoví Juan, Antonio M. Casas Sainz, Javier Gracia Abadias, Carlos L. Liesa Carrera
International Journal of Speleology
Evaluation of karst hazards benefits from the integration of different techniques, methodologies and approaches. Each one presents a different signature and is sensitive to certain indicators related to karst hazards. In some cases, detailed analysis permits the evaluation of representativeness either from isolated approaches or by means of integrated analyses. In this study, we present the evaluation of an area with high density of karstic collapses at different evolutionary stages through the integration of surficial, historical, geomorphological and geophysical data in order to finally define the evolutionary model for karst activity development. The obtained dataset permits to identify different steps …
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
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, …
Constraining Boundaries And Extent Of The Charleston Uplift, Northeast New Madrid Seismic Zone, Using Shallow Seismic Reflection Methods, Clara Rose Rucker
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 …
Potential Field Modeling Across The Neodymium Line Defining The Paleoproterozoic-Mesoproterozoic Boundary Of The Southeastern Margin Of Laurentia, Rachel Lauren Durham
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 (TDM) 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 …
Improved 2d And 3d Resistivity Surveys Using Buried Electrodes And Optimized Arrays: The Multi-Electrode Resistivity Implant Technique (Merit), Henok Gidey Kiflu
Improved 2d And 3d Resistivity Surveys Using Buried Electrodes And Optimized Arrays: The Multi-Electrode Resistivity Implant Technique (Merit), Henok Gidey Kiflu
USF Tampa Graduate Theses and Dissertations
This thesis presents a novel resistivity method called Multi-Electrode resistivity technique (MERIT) that is used for high resolution imaging of complex geologic features at depth and near the edges of survey lines. The MERIT electrodes are especially shaped and designed to be self-driven using a robust-direct push technique. Measurements are taken using optimized arrays that are generated using a modified version of the “Compare-R” optimization algorithm. This work focused on both two-dimensional (MERIT2D) and three-dimensional (MERIT3D) applications of the buried array and show the relevance of the additional information gained by the addition of deep electrodes especially in sites with …
Basal Characteristics Of The Main Sticky Spot On The Ice Plain Of Whillans Ice Stream, Antarctica, Tarun Luthra, Sridhar Anandakrishnan, J. Paul Winberry, Richard B. Alley, Nicholas Holschuh
Basal Characteristics Of The Main Sticky Spot On The Ice Plain Of Whillans Ice Stream, Antarctica, Tarun Luthra, Sridhar Anandakrishnan, J. Paul Winberry, Richard B. Alley, Nicholas Holschuh
Geological Sciences Faculty Scholarship
Understanding the processes that affect streaming ice flow and the mass balance of glaciers and ice sheets requires sound knowledge of their subglacial environments. Previous studies have shown that an extensive deformable subglacial sediment layer favors fast ice-stream flow. However, areas of high basal drag, termed sticky spots, are of particular interest because they inhibit the fast flow of the overriding ice. The stick-slip behavior of Whillans Ice Stream (WIS) is perhaps the most conspicuous manifestation of a subglacial sticky spot. We present new ice-thickness and seismic-reflection measurements collected over the main sticky spot in the ice plain of WIS, …