Open Access. Powered by Scholars. Published by Universities.®
- Institution
-
- Western Michigan University (19480)
- University of Kentucky (10978)
- University of Nebraska - Lincoln (4538)
- University of South Florida (1880)
- China Coal Technology and Engineering Group (CCTEG) (1799)
-
- Department of Primary Industries and Regional Development, Western Australia (1669)
- Utah State University (1564)
- TÜBİTAK (917)
- Missouri University of Science and Technology (776)
- University of Arkansas, Fayetteville (763)
- Boise State University (667)
- Portland State University (667)
- Old Dominion University (663)
- University of Nevada, Las Vegas (521)
- University of Texas Rio Grande Valley (519)
- Montana Tech Library (496)
- Western Kentucky University (496)
- University of Colorado Law School (481)
- University of North Dakota (448)
- Louisiana State University (423)
- University of New Mexico (402)
- Montclair State University (383)
- Central Washington University (368)
- City University of New York (CUNY) (315)
- University of Texas at El Paso (315)
- University of South Carolina (275)
- Michigan Technological University (253)
- Brigham Young University (240)
- University of Texas at Arlington (237)
- University of New Hampshire (230)
- Keyword
-
- Western Australia (1183)
- Geology (900)
- Grains and field crops (625)
- Groundwater (620)
- Nebraska (589)
-
- Climate change (461)
- Grazing (407)
- Geochemistry (403)
- Soil (372)
- Hydrology (358)
- Montana (326)
- Nitrogen (323)
- Kentucky (302)
- Remote sensing (282)
- Salinity (282)
- Water quality (280)
- Drought (277)
- Utah (272)
- Water (240)
- Karst (233)
- Alfalfa (223)
- Geophysics (221)
- Climate (219)
- Hydrogeology (214)
- Phosphorus (213)
- Agriculture (203)
- Geomorphology (203)
- Stratigraphy (203)
- Irrigation (202)
- United States (191)
- Publication Year
- Publication
-
- Legacy Scout Tickets from Pure Oil Company (11044)
- IGC Proceedings (1977-2023) (9261)
- Thin Sections (6677)
- Coal Geology & Exploration (1799)
- Legacy Color Lithology Strip Logs (1152)
-
- United States Geological Survey: Staff Publications (1026)
- Turkish Journal of Earth Sciences (917)
- Conservation and Survey Division: Faculty and Staff Publications (901)
- International Journal of Speleology (889)
- Theses and Dissertations (826)
- Department of Earth and Atmospheric Sciences: Faculty Publications (670)
- Experimental Summaries - Plant Research (668)
- Masters Theses (591)
- All Graduate Theses and Dissertations, Spring 1920 to Summer 2023 (454)
- School of Earth, Environmental, & Marine Sciences Faculty Publications (428)
- Bachelors Theses and Reports, 1928 - 1970 (423)
- Faculty Publications (407)
- Geosciences Faculty Publications and Presentations (393)
- Kentucky Alfalfa and Stored Forage Conference (382)
- School of Geosciences Faculty and Staff Publications (355)
- Dissertations and Theses (343)
- Earth and Planetary Sciences ETDs (343)
- Graduate Theses and Dissertations (339)
- Electronic Theses and Dissertations (326)
- Memorandum (316)
- Resource management technical reports (315)
- Open Access Theses & Dissertations (294)
- Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works (280)
- USF Tampa Graduate Theses and Dissertations (272)
- Department of Earth and Environmental Studies Faculty Scholarship and Creative Works (262)
- Publication Type
Articles 49861 - 49890 of 59446
Full-Text Articles in Entire DC Network
Defining Archaeological Stratigraphy: Evaluating Microartifact Sampling, David N. Holycross
Defining Archaeological Stratigraphy: Evaluating Microartifact Sampling, David N. Holycross
All-Inclusive List of Electronic Theses and Dissertations
A variety of subsurface methods have been used to discover and evaluate buried archaeological occupations. Researchers such as Stafford (1993,1995) have proposed that micro artifacts are an effective means of defining the archaeological stratigraphy of deposits, but only limited evaluation of this approach has been undertaken. This study tested the utility of microartifacts within a range of sample size and site density characteristics at three Ohio Valley archaeological sites buried within early and late Holocene age landforms. Occupations were typically detected in unit-to-core comparisons, within acceptable margins of error, and microartifacts often revealed a more complex stratigraphy than reflected by …
Quantitative Analysis Of Movement Along An Earthquake Thrust Scarp: A Case Study Of A Vertical Exposure Of The 1999 Surface Rupture Of The Chelungpu Fault At Wufeng, Western Taiwan, Jian-Cheng Lee, Charles Rubin, Karl Mueller, Yue-Gau Chen, Yu-Chang Chan, Kerry Sieh, Hao-Tsu Chu, Wen-Shan Chen
Quantitative Analysis Of Movement Along An Earthquake Thrust Scarp: A Case Study Of A Vertical Exposure Of The 1999 Surface Rupture Of The Chelungpu Fault At Wufeng, Western Taiwan, Jian-Cheng Lee, Charles Rubin, Karl Mueller, Yue-Gau Chen, Yu-Chang Chan, Kerry Sieh, Hao-Tsu Chu, Wen-Shan Chen
All Faculty Scholarship for the College of the Sciences
A vertical exposure across the principal thrust scarp of the 1999 Mw 7.6 earthquake allows quantification of fault slip. The exposure is located on the active Chelungpu fault near Wufeng, along the range front of the fold-and-thrust belt in western Taiwan. The 1999 surface ruptures at the Wufeng site are characterized by a west-facing 2 to 3 m high principal thrust scarp and an east-facing lesser backthrust scarp. We mapped a 15 m-long, 5 m-deep exposure across the principal thrust scarp and characterized complex deformation structures, which include a main basal thrust fault, a wedge thrust, and a pop-up anticlinal …
Terrestrial Movements And Habitat Use Of Gopher Frogs (Rana Capito) At Fort Benning, Georgia, Jonathan H. Neufeldt
Terrestrial Movements And Habitat Use Of Gopher Frogs (Rana Capito) At Fort Benning, Georgia, Jonathan H. Neufeldt
Theses and Dissertations
Gopher frogs (Rana capito) were radio-tracked between the 2000 and 2001 breeding seasons to study their terrestrial movements and habitat use in a longleaf pine- sandhill area on the Fort Benning Military Reservation, Georgia. The telemetry research was conducted in response to the need for biological data concerning gopher frog terrestrial habits. Ultimately the data could aid biologists and land managers in describing critical habitat and the development of a management or recovery plan. Twelve gopher frogs were caught at a herpetofaunal array surrounding two neighboring breeding ponds during a post breeding migration, implanted with miniature transmitters, released and radio-tracked …
Sulfide Sulfur Concentration And Sulfur Isotopic Composition Of Methane Seep Sediments, V. Lynn Means, Walter S. Borowski
Sulfide Sulfur Concentration And Sulfur Isotopic Composition Of Methane Seep Sediments, V. Lynn Means, Walter S. Borowski
EKU Faculty and Staff Scholarship
No abstract provided.
Structural Geology And Aquifer Characterization Of Glassy Mountain, South Carolina Piedmont, Cameron M. Warlick
Structural Geology And Aquifer Characterization Of Glassy Mountain, South Carolina Piedmont, Cameron M. Warlick
All Dissertations
Lithologies and structures of the Inner Piedmont geological province were mapped in detail in the vicinity of a major, new residential development on Glassy Mountain, which is located north of Greenville, South Carolina, within the Saluda 7.5-minute quadrangle. Three principal lithostratigraphic units are recognized within the study area: the Henderson Gneiss, Upper Mill Spring unit, and Poor Mountain Formation. The contact between the Henderson Gneiss and the overlying Upper Mill Spring-Poor Mountain sequence is the Seneca Thrust. The contact between the Upper Mill Spring unit and the overlying Poor Mountain Formation is also a thrust fault. Fold vergence and thrust …
“Coupling” Semantics And Science In Earthquake Research, Kelin Wang, Timothy H. Dixon
“Coupling” Semantics And Science In Earthquake Research, Kelin Wang, Timothy H. Dixon
School of Geosciences Faculty and Staff Publications
Coupling is a convenient word that describes a wide variety of interactions or feedback processes, including those that we do not fully understand. Examples in Earth science include ocean-atmosphere coupling, climate-tectonics coupling, and core-mantle coupling. The word is also very popular in discussions of plate boundary earthquake processes.
As a vague expression, fault coupling is a perfectly adequate term, describing some kind of mechanical interaction between rocks of each side of a fault. For those of us who try to infer fault processes from geodetic measurements, coupling usually indicates a state of no or low current slip. If a fault …
Hydraulic Testing Of The Big Hole Fault, Northern San Rafael Swell, Utah, William M. Schieb
Hydraulic Testing Of The Big Hole Fault, Northern San Rafael Swell, Utah, William M. Schieb
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Six cross-hole packer tests were conducted at the Big Hole fault, a dip-slip normal fault in the northern San Rafael Swell of east-central Utah. Three tests were conducted at each of two locations along the fault, each location having a different total displacement. Water was injected in the footwall, hanging wall, and fault core and pressure changes were monitored in isolated intervals in the adjoining wells. Response curves were analyzed using the type curves developed by Hsieh and Neuman, and Theis, in order to evaluate the hydraulic properties of the fault and its associated damage zone.
The tests were not …
Structural Analysis Of Co2 Leakage Through The Salt Wash And Little Grand Wash Faults From Natural Reservoirs In The Colorado Plateau, Southeastern Utah, Anthony P. Williams
Structural Analysis Of Co2 Leakage Through The Salt Wash And Little Grand Wash Faults From Natural Reservoirs In The Colorado Plateau, Southeastern Utah, Anthony P. Williams
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
The Little Grand Wash fault and the Salt Wash Graben in the Colorado Plateau of southeastern Utah emit CO2 gas from abandoned drillholes, springs, and a hydrocarbon seep. Similar CO2-charged water has also been emitted in the past, as shown by large localized travertine deposits and veins along and near the fault traces. The faults cut natural CO2 reservoirs and provide an excellent analog for geologic CO2 sequestration. The faults cut a north-plunging anticline of rocks consisting of siltstones, shales, and sandstones from the Permian Cutler Formation through the Cretaceous Mancos Shale. The Little Grand …
Geochemistry Of Ground Water - Surface Water Interactions And Metals Loading Rates In The North Fork Of The American Fork River, Utah, From An Abandoned Silver/Lead Mine, Neil I. Burk
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
The aqueous geochemistry and hydrology of the North Fork of the American Fork River, its tributaries, and the ground water in the vicinity of the Pacific Mine site were investigated in order to determine what impact ground water entering the North Fork has on toxic metal loads in the river. Toxic metal contamination in the North Fork is great enough that brown and cutthroat trout have absorbed lead, cadmium, and arsenic in their tissues at concentrations that are hazardous to human health if consumed. Ground water that flows through the mine site flows directly through the mine tailings before entering …
Waldo Lake Research In 2003, Mark D. Sytsma, John Rueter, Richard Petersen, Roy Koch, Scott A. Wells, Rich Miller, Laura Johnson, Robert Leslie Annear
Waldo Lake Research In 2003, Mark D. Sytsma, John Rueter, Richard Petersen, Roy Koch, Scott A. Wells, Rich Miller, Laura Johnson, Robert Leslie Annear
Civil and Environmental Engineering Faculty Publications and Presentations
This report summarizes the first year of an effort to develop a more complete understanding of the physical, chemical, and biological characteristics that drive the ecological processes of Waldo Lake. Modern limnology recognizes the importance of watershed processes as well as in- lake processes in lake ecosystem functioning. Therefore, the approach included consideration of watershed hydrology and forcing functions that determine hydrodynamics of the system as well physical and chemical factors that may be important in regulating primary production in the lake. Data collected since 1998 was summarized and bathymetry of the basin was mapped using state-of-the-art digital depth sounding …
Spatial Variation In The Response Of Tree Rings To Normal Faulting During The Hebgen Lake Earthquake, Southwestern Montana, Usa, Matthew F. Bekker
Spatial Variation In The Response Of Tree Rings To Normal Faulting During The Hebgen Lake Earthquake, Southwestern Montana, Usa, Matthew F. Bekker
Wasatch Dendroclimatology Research
Tree rings have frequently been used to identify the effects of earthquakes on forests, but little is known about spatial variation in the response of trees to intraplate normal faulting. This paper documents and describes the effects of tree location (distance from and position above or below the fault scarp), size and age on the response of tree rings to the 1959 magnitude 7.5 Hebgen Lake earthquake, which occurred along a normal fault in the Gallatin National Forest in southwestern Montana. Core samples from 88 trees were collected along nine 100-m transects straddling the Hebgen scarp, and from 28 additional …
Geologic Context Of Geodetic Data Across A Basin And Range Normal Fault, Crescent Valley, Nevada, A. M. Friedrich, Jeffrey Lee, B. P. Wernicke, K. Sieh
Geologic Context Of Geodetic Data Across A Basin And Range Normal Fault, Crescent Valley, Nevada, A. M. Friedrich, Jeffrey Lee, B. P. Wernicke, K. Sieh
All Faculty Scholarship for the College of the Sciences
Geodetic strain and late Quaternary faulting in the Basin and Range province is distributed over a region much wider than historic seismicity, which is localized near the margins of the province. In the relatively aseismic interior, both the magnitude and direction of geodetic strain may be inconsistent with the Holocene faulting record. We document the best example of such a disagreement across the NE striking, ∼55° NW dipping Crescent normal fault, where a NW oriented, 70 km geodetic baseline records contemporary shortening of ∼2 mm/yr orthogonal to the fault trace. In contrast, our geomorphic, paleoseismic, and geochronologic analyses of the …
Tectonic Significance Of Topographic Lineament Analysis Using Artificial Illumination: Offshore Southwestern Taiwan, Jinder Chow, Tzun-Der Lai, Char-Shine Liu, Robert Sun
Tectonic Significance Of Topographic Lineament Analysis Using Artificial Illumination: Offshore Southwestern Taiwan, Jinder Chow, Tzun-Der Lai, Char-Shine Liu, Robert Sun
Journal of Marine Science and Technology–Taiwan
A digital topographic relief map, shaded by means of artificial illumination, has been compiled for southwestern Taiwan for a lineament analysis of the area. We discover a pronounced fanning toward the southwest in the lineaments. Six major offsets of lineaments have been identified, with the following trends: N60°E, N60°E, N65°E, N85°E, and N40°W. The trends of the offsets can all be correlated with faults predicted by experimental models of right-lateral strikeslip deformation. This paper presents a detailed submarine topographic lineament analysis in southwestern Taiwan and provides additional evidence of Lu's model for the vast offshore area.
Crossing A Narrow-In-Altitude Turbulent Auroral Acceleration Region, R. Pottelette, R. A. Treumann, E. Georgescu
Crossing A Narrow-In-Altitude Turbulent Auroral Acceleration Region, R. Pottelette, R. A. Treumann, E. Georgescu
Dartmouth Scholarship
We report on the in situ identification of a narrow electrostatic acceleration layer (electrostatic shock) containing intense plasma turbulence in the upward current region, and its effect on auroral particles. Wave turbulence recorded in the center of the layer differs in character from that recorded above and beneath. It is concluded that the shock is sustained by different nonlinear waves which, at each level, act on the particles in such a way to produce a net upward directed electric field. The main power is in the ion acoustic range. We point out that anomalous resistivities are incapable of locally generating …
The Effects Of Polychlorinated Biphenyls (Pcbs) On Nerve Growth Factor (Ngf) In The Developing Frog, Xenopus Laevis, Cari Delong
The Effects Of Polychlorinated Biphenyls (Pcbs) On Nerve Growth Factor (Ngf) In The Developing Frog, Xenopus Laevis, Cari Delong
Honors Theses
Polychlorinated biphenyls are ubiquitous, persistent environmental contaminants that cause a variety of adverse health effects wildlife and humans. PCBs are the major contaminant in the Kalamazoo River Superfund Site, in which the Environmental Institute is funded to study. Projects at the Environmental Institute are focused on developing molecular biotechnology tools that will improve environmental risk assessment. Previous acute studies involved the exposure of developing tadpoles, Xenopus laevis to PCBs through aquarium water in order to measure gene expression. Nerve growth factor (NGF) gene expression showed changes in these previous studies. NGF is a neurotrophic factor that regulates the growth and …
Re-Evaluation Of So2 Release Of The 15 June 1991 Pinatubo Eruption Using Ultraviolet And Infrared Satellite Sensors, Song Guo, Gregg J. S. Bluth, William I. Rose, M. I. Watson, A. J. Prata
Re-Evaluation Of So2 Release Of The 15 June 1991 Pinatubo Eruption Using Ultraviolet And Infrared Satellite Sensors, Song Guo, Gregg J. S. Bluth, William I. Rose, M. I. Watson, A. J. Prata
Department of Geological and Mining Engineering and Sciences Publications
In this study, ultraviolet TOMS (Total Ozone Mapping Spectrometer) satellite data for SO2 are re-evaluated for the first 15 days following the 15 June 1991 Pinatubo eruption to reflect new data retrieval and reduction methods. Infrared satellite SO2 data from the TOVS/HIRS/2 (TIROS (Television Infrared Observation Satellite) Optical Vertical Sounder/High Resolution Infrared Radiation Sounder/2) sensor, whose data sets have a higher temporal resolution, are also analyzed for the first time for Pinatubo. Extrapolation of SO2 masses calculated from TOMS and TOVS satellite measurements 19–118 hours after the eruption suggest initial SO2 releases of 15 ± 3 …
Keith County Test-Hole Logs: Nebraska Water Survey Test-Hole Report No. 51, Robert F. Diffendal Jr., James W. Goeke
Keith County Test-Hole Logs: Nebraska Water Survey Test-Hole Report No. 51, Robert F. Diffendal Jr., James W. Goeke
Robert F. Diffendal, Jr., Publications
In 1930, the Conservation and Survey Division (CSD) of the University of Nebraska and the U.S. Geological Survey began a program of cooperative groundwater studies in Nebraska. Since then test drilling by use of rotary drilling equipment has been an integral part of that program. This report contains logs of all the test holes drilled in the county under the program as well as those drilled by the Conservation and Survey Division with financial assistance from other government agencies.
The maps in this report show the locations of all test holes drilled in the county since 1934.
Present techniques of …
A North Dakota Geology Field Trip Primer, Joseph H. Hartman
A North Dakota Geology Field Trip Primer, Joseph H. Hartman
Geology and Geological Engineering Faculty Publications
The rocks containing vertebrate fossils in North Dakota represent an important archive of biological and geological events that took place from around 80 million years ago to the present (Figure 1). Although the record is not complete through this interval of time, significant exposures provide important sections of Earth’s geologic history (Figure 2). We continue to understand better how seas moved back and forth across North Dakota and the life that persisted in these seas and adjacent estuaries. The terrestrial habitats and river drainages that are recorded in nonmarine strata contain important insights into the patterns of dinosaur diversity up …
Tropical Westerlies Over Pangaean Sand Seas, David B. Loope, Maureen B. Steiner, Clinton M. Rowe, Nicholas Lancaster
Tropical Westerlies Over Pangaean Sand Seas, David B. Loope, Maureen B. Steiner, Clinton M. Rowe, Nicholas Lancaster
Department of Earth and Atmospheric Sciences: Faculty Publications
Cross-equatorial, westerly winds are key features of tropical circulation in monsoonal regions. Although prominent in numerical climate models of Pangaea (the supercontinent straddling earth’s equator, Late Paleozoic to Early Mesozoic), such flow has not been confirmed previously by migration directions of ancient dunes. Windblown sandstones that span 100 million years of earth history are widely exposed in south-western USA. If recent paleomagnetic data from the Colorado Plateau are used to correct Mesozoic paleogeographic maps, the Plateau is placed about 10° further south than previously assumed, and the prevailing north-westerly surface winds recorded by dune-deposited sandstones are explicable as cross-equatorial westerlies …
Prairie Wetlands Are Important For Carbon Storage, Jay Hestbeck
Prairie Wetlands Are Important For Carbon Storage, Jay Hestbeck
United States Geological Survey: Publications
USGS’s Northern Prairie Wildlife Research Center and USDA’s Agricultural Research Service collaborated to study the potential of prairie pothole region wetlands to sequester carbon emitted into the atmosphere from the burning of fossil fuels. Results suggest that wetlands traditionally functioned as sinks for atmospheric carbon, but cultivation, the current principal land use, has shifted their function to be sources of atmospheric carbon. Data suggest that equal or greater amounts of atmospheric carbon can be stored in wetlands through restoration programs when compared with cropland, even though the acreage of wetlands is much smaller. These restored wetlands will also provide improved …
Chemical And Isotopic Investigation Of Groundwater In Eastern United Arab Emirates (Uae), Ahmed Ali Abdalla Murad
Chemical And Isotopic Investigation Of Groundwater In Eastern United Arab Emirates (Uae), Ahmed Ali Abdalla Murad
Dissertations
UAE is located at the southeast of Arabian Peninsula. Two main aquifers occupy the study area: the Eastern Gravel Plain and Ophiolite aquifer. Increasing salinity of groundwater and depletion of aquifers are a major concern in the UAE. Previous studies suggest that groundwater, particularly in the Eastern Gravel Plain aquifer, is affected by seawater intrusion and evaporation. Isotopes of oxygen, hydrogen, carbon and chlorine, and chemical analyses were used to investigate this problem in detail. Samples of groundwater from the Eastern Gravel Plain aquifer have R36Cl values in the range of 13.3 to 17.4 x10-15 while those …
Willamette River Basin Temperature Tmdl Model: Model Scenarios, Robert Leslie Annear, Michael Lee Mckillip, Sher Jamal Khan, Chris Berger, Scott A. Wells
Willamette River Basin Temperature Tmdl Model: Model Scenarios, Robert Leslie Annear, Michael Lee Mckillip, Sher Jamal Khan, Chris Berger, Scott A. Wells
Civil and Environmental Engineering Faculty Publications and Presentations
The State of Oregon Department of Environmental Quality (DEQ) is developing a TMDL for temperature in the Willamette River basin shown in Figure 1. The study area included the Willamette River and all major tributaries (except the Tualatin River where a TMDL process was already concluded). A large section of the Columbia River was also modeled to provide adequate boundary representation of tidal flows in the lower Willamette River. The Willamette River below the Oregon City Falls in the Portland metropolitan area has a typical diurnal tidal range of 1 m. The development of a dynamic model of temperature and …
Isotopic Concentration Of Sulfide Sulfur And Delta-34s From Methane Seeps On The Blake Ridge Diapir And Monterey Canyon, V. Lynn Means, Walter S. Borowski
Isotopic Concentration Of Sulfide Sulfur And Delta-34s From Methane Seeps On The Blake Ridge Diapir And Monterey Canyon, V. Lynn Means, Walter S. Borowski
EKU Faculty and Staff Scholarship
Marine sediments contain pore water with dissolved sulfate. Pore-water sulfate is depleted by two anaerobic chemical reactions tat involves microbes: 1) oxidation of sedimentary organic matter; and 2) anaerobic methane oxidation (AMO; CH4 + SO4 → HCO3- + HS- + H2O). Both sulfate depletion pathways produce dissolved hydrogen sulfide (∑HS-), which is scavenged by dissolved iron to produce authigenic sulfide minerals. These minerals crystallize in pore spaces or on grain surfaces. Seafloor seeps are where methane moves upward in the sediments to escape into overlying waters. Additional methane supply should fuel …
Relating Water And Otolith Chemistry In Chesapeake Bay, And Their Potential To Identify Essential Seagrass Habitats For Juveniles Of An Estuarine-Dependent Fish, Spotted Seatrout (Cynoscion Nebulosus), Emmanis Dorval
Biological Sciences Theses & Dissertations
A quantitative understanding of habitat use of estuarine-dependent fishes is critical to the conservation of their most essential habitats. Because recruitment and fitness may be influenced by the quality of juvenile habitats, developing methods to quantify habitat-specific survivorship is pivotal to such understanding. An initial step to quantify survivorship is to validate the habitat-specific natural tags contained in otoliths. To this aim I investigated the variability in the chemistry of surface waters and otoliths of juvenile spotted seatrout, Cynoscion nebulosus, in five seagrass habitats of Chesapeake Bay, namely: Potomac, Rappahannock, York, Island, and Eastern Shore. I measured Mg, Ca, …
Error Analysis Of Continuous Gps Position Time Series, Simon D. P. Williams, Yehuda Bock, Peng Fang, Paul Jamason, Rosanne M. Nikolaidis, Linette Prawirodirdjo, Meghan Miller, Daniel J. Johnson
Error Analysis Of Continuous Gps Position Time Series, Simon D. P. Williams, Yehuda Bock, Peng Fang, Paul Jamason, Rosanne M. Nikolaidis, Linette Prawirodirdjo, Meghan Miller, Daniel J. Johnson
All Faculty Scholarship for the College of the Sciences
A total of 954 continuous GPS position time series from 414 individual sites in nine different GPS solutions were analyzed for noise content using maximum likelihood estimation (MLE). The lengths of the series varied from around 16 months to over 10 years. MLE was used to analyze the data in two ways. In the first analysis the noise was assumed to be white noise only, a combination of white noise plus flicker noise, or a combination of white noise plus random walk noise. For the second analysis the spectral index and amplitude of the power law noise were estimated simultaneously …
Explosion Dynamics Of Pyroclastic Eruptions At Santiaguito Volcano, Jeffrey B. Johnson, Andrew J. L. Harris, Steve T. M. Sahetapy-Engel, Rudiger Wolf, William I. Rose
Explosion Dynamics Of Pyroclastic Eruptions At Santiaguito Volcano, Jeffrey B. Johnson, Andrew J. L. Harris, Steve T. M. Sahetapy-Engel, Rudiger Wolf, William I. Rose
Department of Geological and Mining Engineering and Sciences Publications
In Jan. 2003 we monitored explosions at Santiaguito Volcano (Guatemala) with thermal, infrasonic, and seismic sensors. Thermal data from 2 infrared thermometers allowed computation of plume rise speeds, which ranged from 8 to 20 m/s. Rise rates correlated with cumulative thermal radiance, indicating that faster rising plumes correspond to explosions with greater thermal flux. The relationship between rise speeds and elastic energy is less clear. Seismic radiation may not scale well with thermal output and/or rise speed because some of the thermal component may be associated with passive degassing, which does not induce significant seismicity. But non-impulsive gas release is …
Detection Of Arbitrarily Large Dynamic Ground Motions With A Dense High-Rate Gps Network, Yehuda Bock, Linette Prawirodirdjo, Timothy I. Melbourne
Detection Of Arbitrarily Large Dynamic Ground Motions With A Dense High-Rate Gps Network, Yehuda Bock, Linette Prawirodirdjo, Timothy I. Melbourne
All Faculty Scholarship for the College of the Sciences
We describe the detection of teleseismic surface waves from the 3 November 2002 Mw 7.9 Denali fault earthquake in Alaska with a dense network of 1 Hz GPS stations in southern California, about 3900 km from the event. Relative horizontal displacements with amplitudes in excess of 15 mm and duration of 700 seconds agree with integrated velocities recorded by nearby broadband seismometers with an rms difference of 2–3 mm. The displacements are derived from independent 1 Hz instantaneous positions demonstrating that a GPS network can provide direct measurements of arbitrarily large dynamic and static ground horizontal displacements at periods longer …
Time Dependent Mechanical Behavior Of Welded Tuff, Jaak J.K. Daemen, George Danko, Amy J. Smiecinski
Time Dependent Mechanical Behavior Of Welded Tuff, Jaak J.K. Daemen, George Danko, Amy J. Smiecinski
Publications (YM)
This part of the Technical Report includes four types of experimental studies: strain rate dependence, uniaxial creep, Brazilian (Indirect splitting) tensile strength and uniaxial compressive strength. These are presented in four chapters. One hundred twenty one specimens have been tested in uniaxial compression. Ninety three of these are included in the strain rate dependence study, presented in Chapter 2. Uniaxial compression strain rates range from about 10~8 to 10~2 s~l. Results of twenty eight tests are presented in Chapter 5, which describes uniaxial compression testing of specimens containing major lithophysal cavities. Fourteen specimens have been tested in uniaxial creep, presented …
Characterization Of Ground-Water Quality, Upper Republican Natural Resources District, Nebraska, 1998–2001, Jill D. Frankforter, Daniele T. Chafin
Characterization Of Ground-Water Quality, Upper Republican Natural Resources District, Nebraska, 1998–2001, Jill D. Frankforter, Daniele T. Chafin
United States Geological Survey: Publications
Nearly all rural inhabitants and livestock in the Upper Republican Natural Resources District (URNRD) in southwestern Nebraska use ground water that can be affected by elevated nitrate concentrations. The development of ground-water irrigation in this area has increased the vulnerability of ground water to the introduction of fertilizers and other agricultural chemicals. In 1998, the U.S. Geological Survey, in cooperation with the Upper Republican Natural Resources District, began a study to characterize the quality of ground water in the Upper Republican Natural Resources District area with respect to physical properties and concentrations of major ions, coliform bacteria, nitrate, and pesticides, …
Stream Bank Stability In Eastern Nebraska, Philip J. Soenksen, Mary J. Turner, Benjamin J. Dietsch, Andrew Simon
Stream Bank Stability In Eastern Nebraska, Philip J. Soenksen, Mary J. Turner, Benjamin J. Dietsch, Andrew Simon
United States Geological Survey: Publications
Dredged and straightened channels in eastern Nebraska have experienced degradation leading to channel widening by bank failure. Degradation has progressed headward and affected the drainage systems upstream from the modified reaches. This report describes a study that was undertaken to analyze bank stability at selected sites in eastern Nebraska and develop a simplified method for estimating the stability of banks at future study sites. Bank cross sections along straight reaches of channel and geotechnical data were collected at approximately 150 sites in 26 counties of eastern Nebraska. The sites were categorized into three groups based on mapped soil permeability. With …