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Investigation Of Wing Crack Formation With A Combined Phase-Field And Experimental Approach, Sanghyun Lee, Jacqueline E. Reber, Nicholas W. Hayman, Mary F. Wheeler 2017 University of Texas at Austin

Investigation Of Wing Crack Formation With A Combined Phase-Field And Experimental Approach, Sanghyun Lee, Jacqueline E. Reber, Nicholas W. Hayman, Mary F. Wheeler

Jacqueline Reber

Fractures that propagate off of weak slip planes are known as wing cracks and often play important roles in both tectonic deformation and fluid flow across reservoir seals. Previous numerical models have produced the basic kinematics of wing crack openings but generally have not been able to capture fracture geometries seen in nature. Here we present both a phase-field modeling approach and a physical experiment using gelatin for a wing crack formation. By treating the fracture surfaces as diffusive zones instead of as discontinuities, the phase-field model does not require consideration of unpredictable rock properties or stress inhomogeneities around crack ...


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 2017 Universidad de Zaragoza

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 ...


Identifying Irrigated Areas In The Snake River Plain, Idaho: Evaluating Performance Across Composting Algorithms, Spectral Indices, And Sensors, Eric W. Chance, Kelly M. Cobourn, Valerie A. Thomas, Blaine C. Dawson, Alejandro N. Flores 2017 Virginia Polytechnic Institute and State University

Identifying Irrigated Areas In The Snake River Plain, Idaho: Evaluating Performance Across Composting Algorithms, Spectral Indices, And Sensors, Eric W. Chance, Kelly M. Cobourn, Valerie A. Thomas, Blaine C. Dawson, Alejandro N. Flores

Geosciences Faculty Publications and Presentations

There are pressing concerns about the interplay between agricultural productivity, water demand, and water availability in semi-arid to arid regions of the world. Currently, irrigated agriculture is the dominant water user in these regions and is estimated to consume approximately 80% of the world’s diverted freshwater resources. We develop an improved irrigated land-use mapping algorithm that uses the seasonal maximum value of a spectral index to distinguish between irrigated and non-irrigated parcels in Idaho’s Snake River Plain. We compare this approach to two alternative algorithms that differentiate between irrigated and non-irrigated parcels using spectral index values at a ...


Aerodynamic Roughness Length Estimation With Lidar And Imaging Spectroscopy In A Shrub-Dominated Dryland, Aihua Li, Wenguang Zhao, Jessica J. Mitchell, Nancy F. Glenn, Matthew J. Germino, Joel B. Sankey, Richard G. Allen 2017 Boise State University

Aerodynamic Roughness Length Estimation With Lidar And Imaging Spectroscopy In A Shrub-Dominated Dryland, Aihua Li, Wenguang Zhao, Jessica J. Mitchell, Nancy F. Glenn, Matthew J. Germino, Joel B. Sankey, Richard G. Allen

Geosciences Faculty Publications and Presentations

The aerodynamic roughness length (Z0m) serves an important role in the flux exchange between the land surface and atmosphere. In this study, airborne lidar (ALS), terrestrial lidar (TLS), and imaging spectroscopy data were integrated to develop and test two approaches to estimate Z0m over a shrub dominated dryland study area in south-central Idaho, USA. Sensitivity of the two parameterization methods to estimate Z0m was analyzed. The comparison of eddy covariance-derived Z0m and remote sensing-derived Z0m showed that the accuracy of the estimated Z0m heavily depends on the estimation model and the representation of shrub ...


Structural And Stratigraphic Reconstruction Of The Whiting Dome Salt Structure In Viosca Knoll-Mississippi Canyon, Gom, Using 3d Seismic Data, Matthew R. Worrell 2017 Stephen F Austin State University

Structural And Stratigraphic Reconstruction Of The Whiting Dome Salt Structure In Viosca Knoll-Mississippi Canyon, Gom, Using 3d Seismic Data, Matthew R. Worrell

Electronic Theses and Dissertations

Understanding the complexities of salt tectonics is one of the most important factors regarding seismic interpretation of stratigraphy, structure, and geomorphology in the Gulf of Mexico. Evaluating the processes affecting recent mobilization of salt in the shallow, well-imaged section can help provide analogues for older, similar occurrences in the deeper section, thereby providing structural models for the autochthonous salt and its effect on stratigraphy and even potential timing and migration issues of hydrocarbons.

Progradation of delta front and shelf to slope transitional sediments has expulsed and emplaced an allochthonous salt structure (Whiting Dome) in the Viosca Knoll and Mississippi Canyon ...


Gravitational Study Of The Hastings Salt Dome And Associated Faults In Brazoria And Galveston Counties,Texas, Francis C. Okocha 2017 Stephen F. Austin State University

Gravitational Study Of The Hastings Salt Dome And Associated Faults In Brazoria And Galveston Counties,Texas, Francis C. Okocha

Electronic Theses and Dissertations

Salt domes are important geological structures because they are potential major hydrocarbon traps and have a profound effect on overlying strata in the subsurface. Over five hundred salt domes have been located on the United States Gulf Coast region, including the Hastings Salt Dome. Hastings Oil Field is located about 40.2 km (25 miles) southeast of Houston, Texas. The Hasting oil field was discovered in 1934 and it was considered the largest oil reserve on the Gulf Coast. Its peak production of 75,000 BOPD (barrels of oil per day) was recorded in 1977 and it had a cumulative ...


Spatio-Temporal History Of Fluid-Rock Interaction In The Hurricane Fault Zone, Jace Koger 2017 Utah State University

Spatio-Temporal History Of Fluid-Rock Interaction In The Hurricane Fault Zone, Jace Koger

All Graduate Theses and Dissertations

The Hurricane Fault is a 250-km long, west dipping, Basin and Range-bounding normal fault in SW Utah and NW Arizona that initiated in the mid-Miocene to Pliocene. It has been primarily active in the Quaternary, with slip rates of 0.2 – 0.6 mm/yr. There are multiple hot springs along its 250-km length and multiple late Tertiary-Quaternary basaltic centers broadly parallel the fault. Possible sources of hot spring fluids include deeply-circulated meteoric water that experienced water-rock exchange at high temperatures (>100 °C) and deep-seated crustal fluids. Aside from the source of modern hot spring fluids and heat, questions about ...


Developing And Testing A Model Of Site Amplification For Southern Ontario, Sebastian Braganza 2017 Western University

Developing And Testing A Model Of Site Amplification For Southern Ontario, Sebastian Braganza

Electronic Thesis and Dissertation Repository

Commonly-applied methods to estimate ground-motion amplification for earthquake hazard applications in southern Ontario are highly generalized. Site amplification effects have typically been estimated by a parameter that is not well-known in the region, the time-averaged shear-wave velocity in the top 30 metres of soil; VS30. Moreover, VS30 is not well correlated with site amplification in this region. This study develops a model that can better estimate ground motions and shaking intensities in southern Ontario based on readily-available information. The model is based on a site’s peak response frequency (fpeak), which can be estimated from depth-to-bedrock. This ...


Assessing Seasonal And Spatial Variability In The Hydrogeochemistry Of Glacial Meltwater In Iceland, Anisha Tuladhar 2017 Western Kentucky University

Assessing Seasonal And Spatial Variability In The Hydrogeochemistry Of Glacial Meltwater In Iceland, Anisha Tuladhar

Masters Theses & Specialist Projects

A detailed comparative geochemical characterization of three different types of Iceland glacial systems was conducted during June, August, and October, 2016. The study was carried out at a total of 11 outlet glacier rivers flowing from the icecaps Vatnajökull, Eyjafjallajökull, and Mýrdalsjökull. A total of 75 grab samples were collected (25 for each sampling period). The hydrogeochemical variations of Icelandic glacial meltwater are influenced by volcanic activity, temporal changes, and geographical location, which differed between the sampling sites within the glaciers and icecaps. Lower pH range, and comparatively higher and variable specific conductivity, SO4, S and F is linked to ...


Synoptic Atmospheric Conditions, Land Cover, And Equivalent Temperature Variations In Kentucky, Dorothy Yemaa Na-Yemeh 2017 Western Kentucky University

Synoptic Atmospheric Conditions, Land Cover, And Equivalent Temperature Variations In Kentucky, Dorothy Yemaa Na-Yemeh

Masters Theses & Specialist Projects

Research has demonstrated that equivalent temperature (TE), which incorporates both the surface air temperature (T) and moist heat content associated with atmospheric moisture, is a better indicator of overall heat content. This thesis follows up on a study that used TE to determine the impacts of land use/land cover and air masses on the atmospheric heat content over Kentucky during the growing season (April-September). The study, which used data from the Kentucky Mesonet, reveals that moist weather types dominate the growing season and, as expected, differences between T and TE are smaller under dry atmospheric conditions ...


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 2017 Western Michigan University

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

Master's 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 ...


Regional Greenland Accumulation Variability From Operation Icebridge Airborne Accumulation Radar, Gabriel Lewis, Erich Osterberg, Robert Hawley, Brian Whitmore, Hans Peter Marshall, Jason Box 2017 Dartmouth College

Regional Greenland Accumulation Variability From Operation Icebridge Airborne Accumulation Radar, Gabriel Lewis, Erich Osterberg, Robert Hawley, Brian Whitmore, Hans Peter Marshall, Jason Box

CGISS Publications and Presentations

The mass balance of the Greenland Ice Sheet (GrIS) in a warming climate is of critical interest to scientists and the general public in the context of future sea-level rise. An improved understanding of temporal and spatial variability of snow accumulation will reduce uncertainties in GrIS mass balance models and improve projections of Greenland's contribution to sea-level rise, currently estimated at 0.089 ± 0.03 m by 2100. Here we analyze 25 NASA Operation IceBridge accumulation radar flights totaling > 17 700 km from 2013 to 2014 to determine snow accumulation in the GrIS dry snow and percolation zones over ...


Ground-Rupturing Earthquakes On The Northern Big Bend Of The San Andreas Fault, California, 800a.D. To Present, Katherine Scharer, Ray J. Weldon II, Glenn Biasi, Ashley Strieg, Thomas Fumal 2017 U.S. Geological Survey

Ground-Rupturing Earthquakes On The Northern Big Bend Of The San Andreas Fault, California, 800a.D. To Present, Katherine Scharer, Ray J. Weldon Ii, Glenn Biasi, Ashley Strieg, Thomas Fumal

Geology Faculty Publications and Presentations

Paleoseismic data on the timing of ground-rupturing earthquakes constrain the recurrence behavior of active faults and can provide insight on the rupture history of a fault if earthquakes dated at neighboring sites overlap in age and are considered correlative. This study presents the evidence and ages for 11 earthquakes that occurred along the Big Bend section of the southern San Andreas Fault at the Frazier Mountain paleoseismic site. The most recent earthquake to rupture the site was the Mw7.7–7.9 Fort Tejon earthquake of 1857. We use over 30 trench excavations to document the structural and sedimentological evolution ...


Delineation Of Karst Geohazards Along Rm 652 Through The Use Of Ground Penetrating Radar: Culberson County, Texas, Aaron A. Eaves 2017 Stephen F Austin State University

Delineation Of Karst Geohazards Along Rm 652 Through The Use Of Ground Penetrating Radar: Culberson County, Texas, Aaron A. Eaves

Electronic Theses and Dissertations

The Delaware Basin is the western member of the larger Permian Basin, and is located in the Trans-Pecos region of Texas and New Mexico. The Delaware Basin hosts significant evaporite karst geohazards throughout the Gypsum Plain of the Castile Formation, where geohazards of all scales form beneath and immediately adjacent to major infrastructure throughout the region, especially Ranch-to-Market 652, including geohazards ranging from small scale dissolution of road base, to large scale cave and sinkhole development. Gypsum sourced from the Castile and Rustler formations was used to create the road base of this RM652 , which meteoric waters have easily dissolved ...


Particle Dynamics In The Rising Plume At Piccard Hydrothermal Field, Mid-Cayman Rise, Meg Estapa, J. A. Breier, C R. German 2017 Skidmore College

Particle Dynamics In The Rising Plume At Piccard Hydrothermal Field, Mid-Cayman Rise, Meg Estapa, J. A. Breier, C R. German

Meg Estapa

Processes active in rising hydrothermal plumes, such as precipitation, particle aggregation, and biological growth, affect particle size distributions and can exert important influences on the biogeochemical impact of submarine venting of iron to the oceans and their sediments. However, observations to date of particle size distribution within these systems are both limited and conflicting. In a novel buoyant hydrothermal plume study at the recently discovered high-temperature (398°C) Piccard Hydrothermal Field, Mid-Cayman Rise, we report optical measurements of particle size distributions (PSDs). We describe the plume PSD in terms of a simple, power-law model commonly used in studies of upper ...


Observations Of Carbon Export By Small Sinking Particles In The Upper Mesopelagic, Colleen A. Durkin, Meg Estapa, Ken O. Buesseler 2017 Skidmore College

Observations Of Carbon Export By Small Sinking Particles In The Upper Mesopelagic, Colleen A. Durkin, Meg Estapa, Ken O. Buesseler

Meg Estapa

Carbon and nutrients are transported out of the surface ocean and sequestered at depth by sinking particles. Sinking particle sizes span many orders of magnitude and the relative influence of small particles on carbon export compared to large particles has not been resolved. To determine the influence of particle size on carbon export, the flux of both small (11–64 μm) and large (> 64 μm) particles in the upper mesopelagic was examined during 5 cruises of the Bermuda Atlantic Time Series (BATS) in the Sargasso Sea using neutrally buoyant sediment traps mounted with tubes containing polyacrylamide gel layers and tubes ...


Rain Or Snow: Hydrologic Processes, Observations, Prediction, And Research Needs, James P. McNamara 2017 Boise State University

Rain Or Snow: Hydrologic Processes, Observations, Prediction, And Research Needs, James P. Mcnamara

Geosciences Faculty Publications and Presentations

The phase of precipitation when it reaches the ground is a first-order driver of hydrologic processes in a watershed. The presence of snow, rain, or mixed-phase precipitation affects the initial and boundary conditions that drive hydrological models. Despite their foundational importance to terrestrial hydrology, typical phase partitioning methods (PPMs) specify the phase based on near-surface air temperature only. Our review conveys the diversity of tools available for PPMs in hydrological modeling and the advancements needed to improve predictions in complex terrain with large spatiotemporal variations in precipitation phase. Initially, we review the processes and physics that control precipitation phase as ...


Detecting Overpressure Zones By Using Model Based Inversion In Kupe Field, New Zealand, Timucin Cakir 2017 Michigan Technological University

Detecting Overpressure Zones By Using Model Based Inversion In Kupe Field, New Zealand, Timucin Cakir

Dissertations, Master's Theses and Master's Reports

Overpressure is a significant parameter during a drilling process in oil exploration. This phenomenon happens when pore pressure exceeds the limit of hydrostatic pressure in a formation and causes drastic hazards such as blow outs while drilling. This thesis focuses on the determination of possible overpressure areas and studies at three wells in Kupe Field, which is considered to be a natural-gas field in Taranaki Basin. In an effort to identify potential overpressure zones at the Kupe Field, acoustic impedance responses of 3D seismic data for three wells, along with their well log responses were evaluated.

Seismic inversion plays an ...


Time Domain Sar Processing With Gpus For Airborne Platforms, Dustin Lagoy 2017 University of Massachusetts Amherst

Time Domain Sar Processing With Gpus For Airborne Platforms, Dustin Lagoy

Masters Theses May 2014 - current

A time-domain backprojection processor for airborne synthetic aperture radar (SAR) has been developed at the University of Massachusetts’ Microwave Remote Sensing Lab (MIRSL). The aim of this work is to produce a SAR processor capable of addressing the motion compensation issues faced by frequency-domain processing algorithms, in order to create well focused SAR imagery suitable for interferometry. The time-domain backprojection algorithm inherently compensates for non-linear platform motion, dependent on the availability of accurate measurements of the motion. The implementation must manage the relatively high computational burden of the backprojection algorithm, which is done using modern graphics processing units (GPUs), programmed ...


In-Situ Assessment Of Concrete Bridge Decks And Pavements Using Stress-Wave Based Methods, Mengxing Li 2017 Missouri University of Science and Technology

In-Situ Assessment Of Concrete Bridge Decks And Pavements Using Stress-Wave Based Methods, Mengxing Li

Doctoral Dissertations

"Concrete infrastructure of United States is aging and deteriorating. Accurate assessment the condition of concrete infrastructure is critical for its maintenance and rehabilitation. Stress-wave based methods, including ultrasonic surface wave (USW) and impact echo (IE), are becoming popular for characterizing defects and mechanical properties of concrete infrastructures. In this dissertation, a comprehensive literature review of seismic wave theory and common types of defects identified in concrete infrastructures, as well as stress-wave based methods used for concrete infrastructure monitoring and characterizing on a selected concrete bridge deck and two concrete pavement segments are present. The utility and reliability of both methods ...


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