Temporal And Spatial Scales Of Correlation In Marine Phytoplankton Communities,
2019
Old Dominion University
Temporal And Spatial Scales Of Correlation In Marine Phytoplankton Communities, A. M. Kuhn, S. Dutkiewicz, O. Jahn, Sophie Clayton, T. A. Rynearson, M. R. Mazloff, A. D. Barton
OES Faculty Publications
Ocean circulation shapes marine phytoplankton communities by setting environmental conditions and dispersing organisms. In addition, processes acting on the water column (e.g., heat fluxes and mixing) affect the community structure by modulating environmental variables that determine in situ growth and loss rates. Understanding the scales over which phytoplankton communities vary in time and space is key to elucidate the relative contributions of local processes and ocean circulation on phytoplankton distributions. Using a global ocean ecosystem model, we quantify temporal and spatial correlation scales for phytoplankton phenotypes with diverse functional traits and cell sizes. Through this analysis, we address these questions: …
2d Electrical Resistivity And Hydrological Study Of A Solute Plume’S Migration Pathway Through Sandy Loam Within Nacogdoches County, Texas, Usa,
2019
Stephen F Austin State University
2d Electrical Resistivity And Hydrological Study Of A Solute Plume’S Migration Pathway Through Sandy Loam Within Nacogdoches County, Texas, Usa, Tyler Tandy, Wesley Brown, Kevin Stafford
Electronic Theses and Dissertations
combined geophysical and hydrological study was conducted in a sandy loam near the campus of Stephen F. Austin State University in Nacogdoches, Texas. The study area contained three preinstalled piezometers which are located in the Sparta Sand of the Eocene Claiborne Group, a regressive tract of the Eocene sea. Electrical DC resistivity surveys were conducted across one fifty-six-meter-long traverse using AGI’s multi-electrode SuperSting R8 WIFI RES/IP/SP system, which allowed for rapid and reliable data collection. The resistivity line was surveyed using the dipole-dipole array configuration, which has been proven to produce high-quality horizontal resolution. Over the duration of fourteen days, …
Improving Earthquake Disaster Models With Post-Event Data: Insights From The 2015 Gorkha, Nepal Earthquake,
2019
University of Arkansas, Fayetteville
Improving Earthquake Disaster Models With Post-Event Data: Insights From The 2015 Gorkha, Nepal Earthquake, Bradley Steven Wilson
Graduate Theses and Dissertations
Immense amounts of data are collected following earthquake disasters. Yet, it remains unclear how researchers’ might take full advantage of diverse post-disaster datasets. Using data from the 2015 Gorkha Nepal earthquake, this dissertation explores three ways in which post- disaster survey and assessment datasets can be used to inform models of seismic risk, vulnerability, and recovery processes. The first article presents an empirical analysis of scale issues in disaster vulnerability indices using a novel dataset of 750,000 households. This study finds that using aggregated household data to create social vulnerability indices can produce results that are meaningfully different from equivalent …
The Shelf To Basin Transition And Tectonostratigraphy Of The Atoka Formation (Lower Pennsylvanian) In The Arkoma Basin, Northwest Arkansas,
2019
University of Arkansas, Fayetteville
The Shelf To Basin Transition And Tectonostratigraphy Of The Atoka Formation (Lower Pennsylvanian) In The Arkoma Basin, Northwest Arkansas, Travis Gibson White
Graduate Theses and Dissertations
The east-to-west oriented Arkoma Basin is a peripheral foreland basin or depositional trough that developed during the Carboniferous Period. This formation covers an aerial extent of approximately 33,800 square miles and spans from west-central Arkansas into southeastern Oklahoma (McGilvery, Manger, and Zachry, 2016; Perry, 1995). The Atoka Formation, deposited during the early Pennsylvanian, is the largest Paleozoic formation by aerial extent in the state of Arkansas and is located within and comprises the bulk of Arkoma Basin sediments (McFarland, 2004; Nance, 2018). This formation has been informally divided into three divisions, the lower, middle, and upper, based on their stratigraphic …
Crustal Density Variation Of The Eastern U.S.,
2019
University of Kentucky
Crustal Density Variation Of The Eastern U.S., Henglei Zhang, Dhananjay Ravat, Anthony R. Lowry
Earth and Environmental Sciences Research Data
EarthScope’s USArray Transportable Array (TA) has shortcomings for the purpose of interpreting geologic features of wavelengths less than the 70 km TA station spacing, but these can be overcome by using higher spatial resolution gravity data. In this study, we exploit USArray receiver functions to reduce non-uniqueness in the interpretation of gravity anomalies. We model gravity anomalies from previously-derived density variations of sedimentary basins, crustal Vp/Vs variation, Moho variation, and upper mantle density variation derived from body-wave imaging informed by surface wave tomography to estimate Vp/Vs. Although average densities and density contrasts for these seismic variations can be derived, …
Developing And Optimizing Shrub Parameters Representing Sagebrush (Artemisia Spp.) Ecosystems In The Northern Great Basin Using The Ecosystem Demography (Edv2.2) Model,
2019
Boise State University
Developing And Optimizing Shrub Parameters Representing Sagebrush (Artemisia Spp.) Ecosystems In The Northern Great Basin Using The Ecosystem Demography (Edv2.2) Model, Karun Pandit, Hamid Dashti, Nancy F. Glenn, Alejandro N. Flores
Geosciences Faculty Publications and Presentations
Ecosystem dynamic models are useful for understanding ecosystem characteristics over time and space because of their efficiency over direct field measurements and applicability to broad spatial extents. Their application, however, is challenging due to internal model uncertainties and complexities arising from distinct qualities of the ecosystems being analyzed. The sagebrush-steppe ecosystem in western North America, for example, has substantial spatial and temporal heterogeneity as well as variability due to anthropogenic disturbance, invasive species, climate change, and altered fire regimes, which collectively make modeling dynamic ecosystem processes difficult. Ecosystem Demography (EDv2.2) is a robust ecosystem dynamic model, initially developed for tropical …
Recent Precipitation Decrease Across The Western Greenland Ice Sheet Percolation Zone,
2019
Boise State University
Recent Precipitation Decrease Across The Western Greenland Ice Sheet Percolation Zone, Hans-Peter Marshall, Tate Meehan
Geosciences Faculty Publications and Presentations
The mass balance of the Greenland Ice Sheet (GrIS) in a warming climate is of critical interest in the context of future sea level rise. Increased melting in the GrIS percolation zone due to atmospheric warming over the past several decades has led to increased mass loss at lower elevations. Previous studies have hypothesized that this warming is accompanied by a precipitation increase, as would be expected from the Clausius–Clapeyron relationship, compensating for some of the melt-induced mass loss throughout the western GrIS. This study tests that hypothesis by calculating snow accumulation rates and trends across the western GrIS percolation …
Exploring The Law Of Detrital Zircon: La-Icp-Ms And Ca-Tims Geochronology Of Jurassic Forearc Strata, Cook Inlet, Alaska, Usa,
2019
Alaska Division of Geological & Geophysical Surveys
Exploring The Law Of Detrital Zircon: La-Icp-Ms And Ca-Tims Geochronology Of Jurassic Forearc Strata, Cook Inlet, Alaska, Usa, Trystan M. Herriott, James L. Crowley, Mark D. Schmitz, Marwan A. Wartes, Robert J. Gillis
Geosciences Faculty Publications and Presentations
Uranium-lead (U-Pb) geochronology studies commonly employ the law of detrital zircon: A sedimentary rock cannot be older than its youngest zircon. This premise permits maximum depositional ages (MDAs) to be applied in chronostratigraphy, but geochronologic dates are complicated by uncertainty. We conducted laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) and chemical abrasion-thermal ionization mass spectrometry (CA-TIMS) of detrital zircon in forearc strata of southern Alaska (USA) to assess the accuracy of several MDA approaches. Six samples from Middle–Upper Jurassic units are generally replete with youthful zircon and underwent three rounds of analysis: (1) LA-ICP-MS of ∼115 grains, with one date per …
Spatially Extensive Ground‐Penetrating Radar Snow Depth Observations During Nasa's 2017 Snowex Campaign: Comparison With In Situ, Airborne, And Satellite Observations,
2019
Boise State University
Spatially Extensive Ground‐Penetrating Radar Snow Depth Observations During Nasa's 2017 Snowex Campaign: Comparison With In Situ, Airborne, And Satellite Observations, Hans-Peter Marshall
Geosciences Faculty Publications and Presentations
Seasonal snow is an important component of Earth's hydrologic cycle and climate system, yet it remains challenging to consistently and accurately measure snow depth and snow water equivalent (SWE) across the range of diverse snowpack conditions that exist on Earth. The NASA SnowEx campaign is focused on addressing the primary gaps in snow remote sensing in order to gain an improved spatiotemporal understanding of this important resource and to further efforts toward a future satellite‐based snow remote sensing mission. Ground‐penetrating radar (GPR) is an efficient and mature approach for measuring snow depth and SWE. We collected ~1.3 million GPR snow …
Integrating Geochronologic And Instrumental Approaches Across The Bengal Basin,
2019
Old Dominion University
Integrating Geochronologic And Instrumental Approaches Across The Bengal Basin, Elizabeth L. Chamberlain, Steven L. Goodbred, Richard Hale, Michael S. Steckler, Jakob Willinga, Carol Wilson
OES Faculty Publications
Constraining time is of critical importance to evaluating the rates and relative contributions of processes driving landscape change in sedimentary basins. The geomorphic character of the field setting guides the application of geochronologic or instrumental tools to this problem, because the viability of methods can be highly influenced by geomorphic attributes. For example, sediment yield and the linked potential for organic preservation may govern the usefulness of radiocarbon dating. Similarly, the rate of sediment transport from source to sink may determine the maturity and/or light exposure of mineral grains arriving in the delta and thus the feasibility of luminescence dating. …
Extraction And Visualization Of Orientation Data From Virtual Geologic Surfaces With Matlab®,
2019
Missouri University of Science and Technology
Extraction And Visualization Of Orientation Data From Virtual Geologic Surfaces With Matlab®, Avery J. Welker, John Patrick Hogan, Andreas Eckert
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
High-resolution visualization of surfaces of geologic interest, at a multitude of scales, using 3D point cloud technologies provides an opportunity to analyze spatial relationships of surfaces using orientation data. We present a MATLAB® script that produces planar geologic attitude data (e.g., strike, dip, and dip-direction data) from 3D datasets (e.g., point clouds, 3D scanning). The method utilizes Cartesian coordinates of triangular planar surfaces and converts them into matrices of conventional geologic attitude data. Spatial relationships among data points can be investigated, using polar tangent diagrams, stereographic analysis, or geologic curvature analysis. We utilize this script to create "synthetic" graphical plots …
Snow Depth Variability In The Northern Hemisphere Mountains Observed From Space,
2019
Boise State University
Snow Depth Variability In The Northern Hemisphere Mountains Observed From Space, Hans-Peter Marshall
Geosciences Faculty Publications and Presentations
Accurate snow depth observations are critical to assess water resources. More than a billion people rely on water from snow, most of which originates in the Northern Hemisphere mountain ranges. Yet, remote sensing observations of mountain snow depth are still lacking at the large scale. Here, we show the ability of Sentinel-1 to map snow depth in the Northern Hemisphere mountains at 1 km² resolution using an empirical change detection approach. An evaluation with measurements from ~4000 sites and reanalysis data demonstrates that the Sentinel-1 retrievals capture the spatial variability between and within mountain ranges, as well as their inter-annual …
Application Of 3d Salt Modeling: An Example From The Northeastern Gulf Of Mexico,
2019
Western Kentucky University
Application Of 3d Salt Modeling: An Example From The Northeastern Gulf Of Mexico, Adam Mattson
Masters Theses & Specialist Projects
Salt tectonics has important implications for hydrocarbon exploration in saltbearing basins since salt deformation can directly or indirectly form hydrocarbon traps, influence hydrocarbon migration, and can control deepwater depositional systems. In various basins around the globe, extensive research has been conducted on initiation of salt mobilization, subsequent deformation, and eventual cessation, mostly from subsurface two-dimensional (2D) sections. However, 3D seismic data has dominated the petroleum industry for the last 30 years. Despite the plethora of 3D seismic data acquired in salt-bearing basins, there has been hardly any published work on the 3D geometries of complex salt bodies. 3D salt mapping …
The Alleghanian Isthmus As The Trigger Of The Onset Of The Bashkirian Glaciation: Constraints From Warm-Water Benthic Foraminifera,
2019
Boise State University
The Alleghanian Isthmus As The Trigger Of The Onset Of The Bashkirian Glaciation: Constraints From Warm-Water Benthic Foraminifera, Vladimir I. Davydov, Pedro Cózar
Geosciences Faculty Publications and Presentations
The timing of the final collision and particularly the disappearance of the gateway between the Rheic and Tethyan oceans is quite controversial and poorly established. The accurate timing on the gateway closure is vitally important for the understanding of global sea-level fluctuations, ocean circulation, regional and global environments, salinity and reorganization of the thermohaline circulation, enhanced deep water organic carbon production in the western Tethys and the overall decline of atmospheric CO2 concentrations. Here we present a new approach by applying warm-water benthic foraminifera (WWBF) data to precisely constraint the Rheic-Tethys gateway (RTG) closure, utilizing taxonomic and statistical methods. …
Melpf Version 1: Modeling Error Learning Based Post-Processor Framework For Hydrologic Models Accuracy Improvement,
2019
East Carolina University
Melpf Version 1: Modeling Error Learning Based Post-Processor Framework For Hydrologic Models Accuracy Improvement, Rui Wu, Lei Yang, Chao Chen, Sajjad Ahmad, Sergiu M. Dascalu, Frederick C. Harris Jr.
Geosciences Faculty Publications and Presentations
This paper studies how to improve the accuracy of hydrologic models using machine-learning models as post-processors and presents possibilities to reduce the workload to create an accurate hydrologic model by removing the calibration step. It is often challenging to develop an accurate hydrologic model due to the time-consuming model calibration procedure and the nonstationarity of hydrologic data. Our findings show that the errors of hydrologic models are correlated with model inputs. Thus motivated, we propose a modeling-error-learning-based post-processor framework by leveraging this correlation to improve the accuracy of a hydrologic model. The key idea is to predict the differences (errors) …
Earthquake-Rotated Headstones As A Means Of Re-Evaluating Epicentral Location Of The 1944 Massena-Cornwall Earthquake: New York, United States And Ontario, Canada,
2019
St. Lawrence University
Earthquake-Rotated Headstones As A Means Of Re-Evaluating Epicentral Location Of The 1944 Massena-Cornwall Earthquake: New York, United States And Ontario, Canada, Sandra L. Walser, Alexander K. Stewart
The Compass: Earth Science Journal of Sigma Gamma Epsilon
The Massena-Cornwall earthquake (September 5th, 1944) is the largest earthquake in New York state history. Two epicenters have been previously proposed (Milne, 1949; Dewey and Gordon, 1984); however, they are separated by 15 km, an error that could associate each proposed epicenter with two different local faults. Due to the lack of standardized seismic-array data, there is value in approaching this event using an unconventional data set. The methodology of MacDonald and Wentworth (1952) was executed through ArcMap 10.5.1 to yield an area most likely to contain the epicenter. One-hundred fifty-four earthquake-rotated headstones from 15 cemeteries within ~35 km of …
Orientation Of Paleostress Of Raplee Ridge Anticline,
2019
Southern Utah University
Orientation Of Paleostress Of Raplee Ridge Anticline, Loren Randall Holyoak, John S. Maclean
The Compass: Earth Science Journal of Sigma Gamma Epsilon
During the Laramide Orogeny several major folds were formed in Southern Utah, one of those being the Raplee Ridge anticline. Raplee Ridge is approximately eight miles from Mexican Hat, Utah. The San Juan River cuts through the anticline, exposing the Honaker Trail Formation’s beds of shale and limestone with chert nodules. Accompanying the mountain-scale ductile deformation of the Raplee Ridge anticline are decimeter-scale brittle conjugate fractures in the limestone’s chert nodules. The objective of this study is to compare the orientation of paleostress that formed the Raplee Ridge anticline with the conjugate fractures within the chert nodules to see if …
Regional Scale Dryland Vegetation Classification With An Integrated Lidar-Hyperspectral Approach,
2019
Boise State University
Regional Scale Dryland Vegetation Classification With An Integrated Lidar-Hyperspectral Approach, Hamid Dashti, Nancy F. Glenn, Nayani Ilangakoon, Josh Enterkine, Alejandro N. Flores
Geosciences Faculty Publications and Presentations
The sparse canopy cover and large contribution of bright background soil, along with the heterogeneous vegetation types in close proximity, are common challenges for mapping dryland vegetation with remote sensing. Consequently, the results of a single classification algorithm or one type of sensor to characterize dryland vegetation typically show low accuracy and lack robustness. In our study, we improved classification accuracy in a semi-arid ecosystem based on the use of vegetation optical (hyperspectral) and structural (lidar) information combined with the environmental characteristics of the landscape. To accomplish this goal, we used both spectral angle mapper (SAM) and multiple endmember spectral …
Effects Of Electro-Osmotic Consolidation Of Clays And Its Improvement Using Ion Exchange Membranes,
2019
New Jersey Institute of Technology
Effects Of Electro-Osmotic Consolidation Of Clays And Its Improvement Using Ion Exchange Membranes, Lucas Martin
Dissertations
Electro-osmosis is an established method of expediting consolidation of soft, saturated clayey soils compared to commonly used methods, such as preloading with wick drains. In electro-osmotic consolidation a direct current (DC) is applied via inserted electrodes. This causes hydrated ions in the interstitial fluid to migrate to oppositely charged electrodes. Because the clay particles have a negative surface charge, the majority of ions in the interstitial fluid are positively charged. Therefore, the net flow will be towards the negatively charged electrode (cathode), where the water can be removed and thus consolidation is achieved. Certain problems, such as pH changes in …
Machine Learning Predicts Aperiodic Laboratory Earthquakes,
2019
Southern Methodist University
Machine Learning Predicts Aperiodic Laboratory Earthquakes, Olha Tanyuk, Daniel Davieau, Charles South, Daniel W. Engels
SMU Data Science Review
In this paper we find a pattern of aperiodic seismic signals that precede earthquakes at any time in a laboratory earthquake’s cycle using a small window of time. We use a data set that comes from a classic laboratory experiment having several stick-slip displacements (earthquakes), a type of experiment which has been studied as a simulation of seismologic faults for decades. This data exhibits similar behavior to natural earthquakes, so the same approach may work in predicting the timing of them. Here we show that by applying random forest machine learning technique to the acoustic signal emitted by a laboratory …
