Seismic Attenuation, Time Delays And Raypath Bending Of Teleseisms Beneath Uturuncu Volcano, Bolivia,
2021
University of South Florida
Seismic Attenuation, Time Delays And Raypath Bending Of Teleseisms Beneath Uturuncu Volcano, Bolivia, Alexandra K. Farrell
USF Tampa Graduate Theses and Dissertations
A set of 14 teleseismic earthquakes was studied to determine how wave propagation was affected by a presumed magma body beneath Uturuncu volcano, Bolivia. Teleseisms are suitable for study because they are relatively long period, contain purely P waves, and have near-vertical incidence angles. The number of events is small but the events have good signal-to-noise ratios and very similar waveforms for each event so that reliable measurements could be made of arrival times and amplitudes. Attenuation of amplitudes occurs in a NW-SE trend beneath the volcano, 14 by 34 km (long axis NW-SE). Calculated values of the quality factor …
The Importance Of The Study Of Igneous Rocks And Compositions To Constrain The Martian Planetary Evolution,
2021
University of Nevada, Las Vegas
The Importance Of The Study Of Igneous Rocks And Compositions To Constrain The Martian Planetary Evolution, Arya Udry University Of Nevada, Las Vegas, Justin Filiberto, Juliane Gross, Mariek Schmidt, Deanne Rogers, Libby Hausrath, Roger Wiens, Nina Lanza
Geoscience Faculty Research
This white paper summarizes the scientific importance of studying igneous compositions in meteorites, surface samples, and through orbital analyses to better constrain the geology of Mars as a whole and better understand the geological processes that have shaped Mars in the past and present.
Bayesian Seismic Refraction Inversion For Critical Zone Science And Near-Surface Applications,
2021
Department of Geology, University of Maryland, College Park, MD
Bayesian Seismic Refraction Inversion For Critical Zone Science And Near-Surface Applications, Mong-Han Huang, Berit Hudson-Rasmussen, Scott Burdick, Vedran Lekić, Mariel D. Nelson, Kristen E. Fauria, Nicholas Schmerr
Environmental Science and Geology Faculty Research Publications
The critical zone (CZ) is the region of the Earth’s surface that extends from the bottom of the weathered bedrock to the tree canopy and is important because of its ability to store water and support ecosystems. A growing number of studies use active source shallow seismic refraction to explore and define the size and structure of the CZ across landscapes. However, measurement uncertainty and model resolution at depth are generally not evaluated, which makes the identification and interpretation of CZ features inconclusive. To reliably resolve seismic velocity with depth, we implement a Transdimensional Hierarchical Bayesian (THB) framework with reversible-jump …
Distribution And Trends Of Endemic Hawaiian Waterbirds,
2021
U.S. Geological Survey Pacific Island Ecosystems Research Center
Distribution And Trends Of Endemic Hawaiian Waterbirds, Eben H. Paxton, Kevin Brinck, Adonia Henry, Afsheen Siddiqi, Rachel Rounds, Jennifer Chutz
United States Geological Survey: Staff Publications
Four endemic species of wetland-dependent waterbirds occur on the main Hawaiian Islands, all of which have experienced sharp population declines and are listed as endangered species. Twice per year, state-wide surveys are conducted to count waterbirds, but these surveys are evaluated only infrequently. We used a state-space approach to evaluate long-term (1986–2016) and short-term (2006–2016) trends and current distribution and abundance of endemic Hawaiian waterbirds. The most numerous species was the Ae‘o, or Hawaiian Stilt (Himantopus mexicanus knudseni), with a 5-year estimated average abundance of 1,932 individuals, followed by ‘Alae Ke‘oke‘o, or Hawaiian Coot (Fulica alai), …
Deriving Melt Rates At A Complex Ice Shelf Base Using In Situ Radar: Application To Totten Ice Shelf,
2021
British Antarctic Survey, Natural Environment Research Council
Deriving Melt Rates At A Complex Ice Shelf Base Using In Situ Radar: Application To Totten Ice Shelf, Irena Vaňková, Sue Cook, J. Paul Winberry, Keith W. Nicholls, Benjamin K. Galton-Fenzi
Geological Sciences Faculty Scholarship
A phase-sensitive radar (ApRES) was deployed on Totten Ice Shelf to provide the first in situ basal melt estimate at this dynamic East Antarctic ice shelf. Observations of internal ice dynamics at tidal time scales showed that early arrivals from off-nadir reflectors obscure the true depth of the ice shelf base. Using the observed tidal deformation, the true base was found to lie at 1,910–1,950-m depth, at 350–400 m greater range than the first reflection from an ice-ocean interface. The robustness of the basal melt rate estimate was increased by using multiple basal reflections over the radar footprint, yielding a …
Rock Glen Wildlife Area: A Landscape History,
2021
University of Nebraska-Lincoln
Rock Glen Wildlife Area: A Landscape History, Gerry Steinauer, Robert Diffendal Jr.
Robert F. Diffendal, Jr., Publications
Nestled in the hills of southern Jefferson County, Rock Glen Wildlife Management Area, as its name implies, is a rocky land shaped by ancient geological forces, among them, meandering tropical rivers and grinding glacial ice. Euro-American settlers in the region arrived to a picturesque scene: rolling hills cloaked in tallgrass prairie fingered by glens, narrow valleys and canyons, filled with sprawling bur oaks. Too rocky to plow, southern Jefferson County has survived as an island of prairie amidst a sea of cropland. Settlement was not kind to the land. Fire suppression allowed eastern red cedars and other trees to spread, …
Seismic Anisotropy And Mantle Deformation Beneath The Central Sunda Plate,
2021
Missouri University of Science and Technology
Seismic Anisotropy And Mantle Deformation Beneath The Central Sunda Plate, Wenkai Song, Youqiang Yu, Stephen S. Gao, Kelly H. Liu, Yifang Fu
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
The central Sunda plate, which forms the core of Southeast Asia, has been extensively studied based on analyses of data mainly from surface geological observations. In contrast, largely due to the limited coverage by seismic stations in the area, a number of key issues associated with mantle structure and dynamics remain enigmatic. These can possibly be constrained by investigating seismic azimuthal anisotropy in the upper mantle. Here we employ the shear wave splitting technique on three P-to-S converted phases from the core-mantle boundary (PKS, SKKS, and SKS) recorded by 11 stations to systematically explore the spatial variation of azimuthal anisotropy …
Inferring The Subsurface Geometry And Strength Of Slow-Moving Landslides Using 3-D Velocity Measurements From The Nasa/Jpl Uavsar,
2021
University of California, Los Angeles
Inferring The Subsurface Geometry And Strength Of Slow-Moving Landslides Using 3-D Velocity Measurements From The Nasa/Jpl Uavsar, Alexander L. Handwerger, Adam M. Booth, Mong-Han Huang, Eric J. Fielding
Geology Faculty Publications and Presentations
The hazardous impact and erosive potential of slow‐moving landslides depends on landslide properties including velocity, size, and frequency of occurrence. However, constraints on size, in particular, subsurface geometry, are lacking because these types of landslides rarely fully evacuate material to create measurable hillslope scars. Here, we use pixel offset tracking with data from the NASA/JPL Uninhabited Aerial Vehicle Synthetic Aperture Radar to measure the three‐dimensional surface deformation of 134 slow‐moving landslides in the northern California Coast Ranges. We apply volume conservation to infer the actively deforming thickness, volume, geometric scaling, and frictional strength of each landslide. These landslides move at …
Geology Study – Drilling Down At Red Trail Energy,
2021
University of North Dakota
Geology Study – Drilling Down At Red Trail Energy, University Of North Dakota. Energy And Environmental Research Center
EERC Brochures and Fact Sheets
Fact sheet about a 2019–2020 geophysical survey near Richardton, North Dakota. The survey investigated the area’s feasibility as a CO2 storage site, as part of the Red Trail Energy carbon capture and storage (CCS) research effort. Summarizes survey process and results. [This item is an outdated or superseded version and retained for historical purposes only. It may no longer reflect current information, policies, or practices.]
Pacific Northwest Littoral Data,
2021
Portland State University
Pacific Northwest Littoral Data, Curt D. Peterson, Kara E. P. Kingen
Geology Faculty Datasets
This document contains five data tables in PDF file formats, that are used to characterize littoral subcell (beach, river mouth, and inner-shelf) conditions in the Pacific Northwest (PNW) region (Washington, Oregon, and Northern California). These data have been compiled from pre-existing data sets (see citations in Table notes and References, below) for the purposes of predicting possible beach erosion from potential future sea level rise (SLR), as introduced in Kingen (2018) and Peterson et al. (2019, 2020a,b). The five data tables include Heavy-mineral tracers (Table 1), Heavy-mineral data (normalized) (Table 2), Subcell beach profile settings (Table 3), Subcell beach profile …
Extensive Frost Weathering Across Unglaciated North America During The Last Glacial Maximum,
2021
University of Arkansas, Fayetteville
Extensive Frost Weathering Across Unglaciated North America During The Last Glacial Maximum, J. A. Marshall, J. J. Roering, A. W. Rempel, S. L. Shafer, P. J. Bartlein
Geosciences Faculty Publications and Presentations
In unglaciated terrain, the imprint of past glacial periods is difficult to discern. The topographic signature of periglacial processes, such as solifluction lobes, may be erased or hidden by time and vegetation, and thus their import diminished. Belowground, periglacial weathering, particularly frost cracking, may have imparted a profound influence on weathering and erosion rates during past climate regimes. By combining a mechanical frost-weathering model with the full suite of Last Glacial Maximum climate simulations, we elucidate the meters-deep magnitude and continent-spanning expanse of frost weathering across unglaciated North America at ∼21 ka. The surprising extent of modeled frost weathering suggests, …
Boulders As A Lithologic Control On River And Landscape Response To Tectonic Forcing At The Mendocino Triple Junction,
2021
West Virginia University
Boulders As A Lithologic Control On River And Landscape Response To Tectonic Forcing At The Mendocino Triple Junction, Charles Shobe, Georgina Bennett, Gregory Tucker, Kevin Roback, Scott Miller, Joshua Roering
Faculty & Staff Scholarship
Constraining Earth’s sediment mass balance over geologic time requires a quantitative understanding of how landscapes respond to transient tectonic perturbations. However, the mechanisms by which bedrock lithology governs landscape response remain poorly understood. Rock type influences the size of sediment delivered to river channels, which controls how efficiently rivers respond to tectonic forcing. The Mendocino triple junction region of northern California, USA, is one landscape in which large boulders, delivered by hillslope failures to channels, may alter the pace of landscape response to a pulse of rock uplift. Boulders frequently delivered by earthflows in one lithology, the Franciscan mélange, have …
Application Of Compound-Specific Stable Isotopes And Molecular Biomarkers To Paleoclimatic And Paleoecological Reconstructions,
2021
Louisiana State University and Agricultural and Mechanical College
Application Of Compound-Specific Stable Isotopes And Molecular Biomarkers To Paleoclimatic And Paleoecological Reconstructions, Mingqiu Hou
LSU Doctoral Dissertations
Compound-specific stable isotope analysis and biomarker-based paleothermometry have been increasingly applied to for paleoclimate and paleoecology studies. The first project aims to reconstruct the paleoclimate in the Qaidam Basin during the last glacial period. Qaidam Basin in the Northern Tibetan Plateau is a critical eolian factory located at a unique geographic location that links the Westerlies and the Asian summer monsoons. However, how the interactions of two climatic systems influence the paleohydrology that in turn impacts the eolian production in the Qaidam Basin has been seldom explored. Our compound-specific hydrogen isotope and UK 37 temperature data found that the …
Redefining The Age Of The Lower Colorado River, Southwestern United States,
2021
U.S. Geological Survey
Redefining The Age Of The Lower Colorado River, Southwestern United States, R. S. Crow, J. Schwing, K. E. Karlstrom, M. Heizler, P. A. Pearthree, P. K. House, S. Dulin, Susanne U. Jänecke, M. Stelten, L. J. Crossey
Geosciences Faculty Publications
Sanidine dating and magnetostratigraphy constrain the timing of integration of the lower Colorado River (southwestern United States and northern Mexico) with the evolving Gulf of California. The Colorado River arrived at Cottonwood valley (Nevada and Arizona) after 5.24 Ma (during or after the Thvera subchron). The river reached the proto–Gulf of California once between 4.80 and 4.63 Ma (during the C3n.2r subchron), not at 5.3 Ma and 5.0 Ma as previously proposed. Duplication of section across newly identified strands of the Earthquake Valley fault zone (California) probably explains the discrepancy. The data also imply the start of focused plate motion …
Early Mesoproterozoic Evolution Of Midcontinental Laurentia: Defining The Geon 14 Baraboo Orogeny,
2021
Illinois State University
Early Mesoproterozoic Evolution Of Midcontinental Laurentia: Defining The Geon 14 Baraboo Orogeny, L. Gordon Medaris Jr, Brad S. Singer, Brian R. Jicha, David H. Malone, Joshua J. Schwartz, Esther K. Stewart, Amanda Van Lankvelt, Michael L. Williams, Peter W. Reiners
Faculty Publications - Geography, Geology, and the Environment
New geochronologic data from midcontinental Laurentia demonstrate that emplacement of the 1476–1470 Ma Wolf River granitic batholith was not an isolated igneous event, but was accompanied by regional metamorphism, deformation, and sedimentation. Evidence for such metamorphism and deformation is best seen in siliciclastic sedimentary rocks of the Baraboo Interval, which were deposited closely following the 1.65–1.63 Ga Mazatzal orogeny. In Baraboo Interval strata, muscovite parallel to slatey cleavage, in hydrothermal veins, in quartzite breccia, and in metamorphosed paleosol yielded 40Ar/39Ar plateau ages of 1493–1465 Ma. In addition, U–Th–total Pb dating of neoblastic overgrowths on detrital monazite gave an age of …
Geology And Fossils Of North Central Texas (Fort Worth To Mineral Wells): Texas Academy Of Science February 28 2021,
2021
Stephen F Austin State University
Geology And Fossils Of North Central Texas (Fort Worth To Mineral Wells): Texas Academy Of Science February 28 2021, R. Larell Nielson
Faculty Publications
The 2021 Texas Academy of Science Geology field trip will be a virtual field trip that you may run at any time. It will have two parts;Part 1 consists of a video discussion of each stop( https://www.youtube.com/watch?v=EJKSgqtLvw0)and Part 2 consists of this field trip guidebook (for use when visiting each of the locations). The field trip will start at Holiday Park,near Benbrook,southwest of Fort Worth,Texas, and will end at the Mineral Wells Fossil Park, west of Minerals Wells, Texas. T
Investigating The Recent History Of A Changing Planet With Innovative Isotopic Techniques And New Geologic Archives,
2021
University of South Florida
Investigating The Recent History Of A Changing Planet With Innovative Isotopic Techniques And New Geologic Archives, Ryan A. Venturelli
USF Tampa Graduate Theses and Dissertations
Globally averaged Earth surface temperatures indicate a 0.8°C warming since 1880. Though this warming is a result of anthropogenic influence that has exceeded natural forcings, a thorough understanding of Earth's climate system requires a knowledge of changes in global temperatures beyond the instrumental record. To achieve this, we must supplement the temporally limited observational record with proxy records of environmental conditions in the geologic past. Though the foundational questions underlying interrogations of the geologic past are seemingly simple (What happened? When?), the accuracy of their answers depend upon accessibility and availability of geologic materials as well as the capabilities of …
Forest Structure And Climate Change Mitigation Potential: A Case Of Wilolesi And Ikonongo Forested Hills In Iringa Municipality, Tanzania, Evarist Fundisha, Hamidu Seki, Anasia Saria
Tanzania Journal of Science
Vegetation plays major roles in carbon storage and ecosystem functioning by modifying the rate of carbon fluxes thereby mitigating climate change. However, the focus of assessing the potentials for different vegetation on climate change mitigation has for so long been conducted outside cities, towns and municipalities. This study was conducted in Wilolesi and Ikonongo hills located in Iringa as representative of the Municipality forested hills in Tanzania to assess vegetation structure and their potential for climate change mitigation. Random sampling technique was employed to establish 20 rectangular plots of 20 m x 40 m (0.08 ha) in each hill to …
Seismic Attributes Analysis As A Precursor To Hydrocarbon Indicators: A Case Study Of “Ok” Field, Niger Delta,
2021
University of Dar es Salaam
Seismic Attributes Analysis As A Precursor To Hydrocarbon Indicators: A Case Study Of “Ok” Field, Niger Delta, Oluwatoyin Ologe, Mary Olowokere
Tanzania Journal of Science
Seismic data volume was employed to gain more insights into the complexities of the hydrocarbon hosting units within and outside the vicinity of well control in the OK-field Niger Delta to overcome wrong deductions from complexly faulted subsurface configuration for the oilfield exploration programme. The methodology involved integration of well log with seismic data, seismic structural analysis and seismic attributes analysis. Horizons and fault interpretations were carried out to produce subsurface attribute maps. Lithologic panels derived from well log data showed that the study area is characterized by sand-shale interbedding. Two hydrocarbon bearing reservoirs were delineated within the study interval, …
Analyzing The Electricity Consumption And Costs Of Electrical-Powered Machines When There Is Orepass Failure In Underground Mine,
2021
University of Dar es Salaam
Analyzing The Electricity Consumption And Costs Of Electrical-Powered Machines When There Is Orepass Failure In Underground Mine, Bartłomiej Skawina, Abubakary Salama
Tanzania Journal of Science
In underground mining environment where the loss of orepasses is a dominant factor, the mine may face a challenge of improving the loading and hauling operations. Some of the options will be to rehabilitate the lost orepasses, or developing the new ones. When the rehabilitation cost is high, alternative strategies should be applied to compensate for the orepasses failure. One of the possible options is to use diesel or electric Load-Haul-Dumps (LHDs). The use of diesel-powered LHDs will increase heat and gas emissions which increase environmental concerns and ventilation costs, while adoption of electric-powered vehicles needs to be analysed. Therefore, …
