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Book Hydraulic Characterization of Overpressured Tuffs in Central Yucca Flat Nevada Test Site Nye County Nevada

Download or read book Hydraulic Characterization of Overpressured Tuffs in Central Yucca Flat Nevada Test Site Nye County Nevada written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A sequence of buried, bedded, air-fall tuffs has been used extensively as a host medium for underground nuclear tests detonated in the central part of Yucca Flat at the Nevada Test Site. Water levels within these bedded tuffs have been elevated hundreds of meters in areas where underground nuclear tests were detonated below the water table. Changes in the ground-water levels within these tuffs and changes in the rate and distribution of land-surface subsidence above these tuffs indicate that pore-fluid pressures have been slowly depressurizing since the cessation of nuclear testing in 1992. Declines in ground-water levels concurrent with regional land subsidence are explained by poroelastic deformation accompanying ground-water flow as fluids pressurized by underground nuclear detonations drain from the host tuffs into the overlying water table and underlying regional carbonate aquifer. A hydraulic conductivity of about 3 x 10-6 m/d and a specific storage of 9 x 10-6 m-1 are estimated using ground-water flow models. Cross-sectional and three-dimensional ground-water flow models were calibrated to measured water levels and to land-subsidence rates measured using Interferometric Synthetic Aperture Radar. Model results are consistent and indicate that about 2 million m3 of ground water flowed from the tuffs to the carbonate rock as a result of pressurization caused by underground nuclear testing. The annual rate of inflow into the carbonate rock averaged about 0.008 m/yr between 1962 and 2005, and declined from 0.005 m/yr in 2005 to 0.0005 m/yr by 2300.

Book Identification and Characterization of Hydrologic Properties of Fractured Tuff Using Hydraulic and Tracer Tests test Well USW H 4 Yucca Mountain Nye County Nevada

Download or read book Identification and Characterization of Hydrologic Properties of Fractured Tuff Using Hydraulic and Tracer Tests test Well USW H 4 Yucca Mountain Nye County Nevada written by J. R. Erickson and published by . This book was released on 1985 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Detailed Geophysical Fault Characterization in Yucca Flat Nevada Test Site Nevada

Download or read book Detailed Geophysical Fault Characterization in Yucca Flat Nevada Test Site Nevada written by U.S. Department of the Interior and published by CreateSpace. This book was released on 2014-03-04 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt: Yucca Flat is a topographic and structural basin in the northeastern part of the Nevada Test Site (NTS) in Nye County, Nevada (fig. 1). Between the years 1951 and 1992, 659 underground nuclear tests took place in Yucca Flat (U.S. Department of Energy, 2000); most were conducted in large, vertical excavations that penetrated alluvium and the underlying Cenozoic volcanic rocks (U.S. Department of Energy, 2000).

Book Thickness of Surficial Deposits and Tuff in Yucca Flat Nevada Test Site

Download or read book Thickness of Surficial Deposits and Tuff in Yucca Flat Nevada Test Site written by Arthur Thomas Fernald and published by . This book was released on 1970 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Investigation of land subsidence and earth fissures in Cedar Valley Iron County Utah

Download or read book Investigation of land subsidence and earth fissures in Cedar Valley Iron County Utah written by Paul Inkenbrandt and published by Utah Geological Survey. This book was released on 2014-03-12 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt: This 116-page report presents the results of an investigation by the Utah Geological Survey of land subsidence and earth fissures in Cedar Valley, Iron County, Utah. Basin-fill sediments of the Cedar Valley Aquifer contain a high percentage of fine-grained material susceptible to compaction upon dewatering. Groundwater discharge in excess of recharge (groundwater mining) has lowered the potentiometric surface in Cedar Valley as much as 114 feet since 1939. Groundwater mining has caused permanent compaction of fine-grained sediments of the Cedar Valley aquifer, which has caused the land surface to subside, and a minimum of 8.3 miles of earth fissures to form. Recently acquired interferometric synthetic aperture radar imagery shows that land subsidence has affected approximately 100 mi² in Cedar Valley, but a lack of accurate historical benchmark elevation data over much of the valley prevents its detailed quantification. Continued groundwater mining and resultant subsidence will likely cause existing fissures to lengthen and new fissures to form which may eventually impact developed areas in Cedar Valley. This report also includes possible aquifer management options to help mitigate subsidence and fissure formation, and recommended guidelines for conducting subsidence-related hazard investigations prior to development.

Book Applied Hydrogeology of Fractured Rocks

Download or read book Applied Hydrogeology of Fractured Rocks written by B.B.S. Singhal † and published by Springer Science & Business Media. This book was released on 2010-08-20 with total page 415 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hydrogeology is a topical and growing subject as the earth's water resources become scarcer and more vulnerable. More than half of the surface area of continents is covered with hard rocks of low permiability. This book deals comprehensively with the fundamental principles for understanding the hydrogeological characteristics of rocks, as well as exploration techniques and assessment. It also provides in depth discussion on structural mapping, remote sensing, geophysical exploration, GIS, groundwater flow modelling and contaminant transport, field hydraulic testing including tracer tests, groundwater quality, geothermal reservoirs, managed aquifer recharge, and resources assessment and management. Hydrogeological aspects of various lithology groups, including crystalline rocks, volcanic rocks, carbonate rocks and clastic formations have been dealt with separately, using and discussing examples from all over the world. It will be an invaluable text book cum reference source for postgraduate students, researchers, exploration scientists and engineers engaged in the field of groundwater development in fractured rocks. Applied Hydrogeology of Fractured Rocks - Second Edition is thoroughly revised and extended with a new chapter, updated sections, many new examples, and expanded and updated references.

Book Analysis of Fracture in Cores from the Tuff Confining Unit Beneath Yucca Flat Nevada Test Site

Download or read book Analysis of Fracture in Cores from the Tuff Confining Unit Beneath Yucca Flat Nevada Test Site written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The role fractures play in the movement of groundwater through zeolitic tuffs that form the tuff confining unit (TCU) beneath Yucca Flat, Nevada Test Site, is poorly known. This is an important uncertainty, because beneath most of Yucca Flat the TCU lies between the sources of radionuclide contaminants produced by historic underground nuclear testing and the regional carbonate aquifer. To gain a better understanding of the role fractures play in the movement of groundwater and radionuclides through the TCU beneath Yucca Flat, a fracture analysis focusing on hydraulic properties was performed on conventional cores from four vertical exploratory holes in Area 7 of Yucca Flat that fully penetrate the TCU. The results of this study indicate that the TCU is poorly fractured. Fracture density for all fractures is 0.27 fractures per vertical meter of core. For open fractures, or those observed to have some aperture, the density is only 0.06 fractures per vertical meter of core. Open fractures are characterized by apertures ranging from 0.1 to 10 millimeter, and averaging 1.1 millimeter. Aperture typically occurs as small isolated openings along the fracture, accounting for only 10 percent of the fracture volume, the rest being completely healed by secondary minerals. Zeolite is the most common secondary mineral occurring in 48 percent of the fractures observed.

Book A Refined Characterization of the Alluvial Geology of Yucca Flat and Its Effect on Bulk Hydraulic Conductivity

Download or read book A Refined Characterization of the Alluvial Geology of Yucca Flat and Its Effect on Bulk Hydraulic Conductivity written by U.S. Department of the Interior and published by Createspace Independent Publishing Platform. This book was released on 2014-02-19 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: Yucca Flat is an extensional basin in the northeast corner of the Nevada National Security Site, Nye Country, Nevada. The basin formed during the Tertiary as a result of eastward extension, and its dominated my north-trending normal faults.

Book Characterization of Liquid water Percolation in Tuffs in the Unsaturated Zone Yucca Mountain Nye County Nevada

Download or read book Characterization of Liquid water Percolation in Tuffs in the Unsaturated Zone Yucca Mountain Nye County Nevada written by and published by . This book was released on 1989 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: A surface-based borehole investigation currently (1989) is being done to characterize liquid-water percolation in tuffs of Miocene age in the unsaturated zone beneath Yucca Mountain, Nye County, Nevada Active in-situ testing and passive in-situ monitoring will be used in this investigation to estimate the present-day liquid-water percolation (flux). The unsaturated zone consists of a gently dipping sequence of fine-grained, densely fractured, and mostly welded ash-flow tuffs that are interbedded with fine-grained, slightly fractured, non-welded ash-flow and ash-fall tuffs that are partly vitric and zeolitized near the water table. Primary study objectives are to define the water potential field within the unsaturated zone and to determine the in-situ bulk permeability and bulk hydrologic properties of the unsaturated tuffs. Borehole testing will be done to determine the magnitude and spatial distribution of physical and hydrologic properties of the geohydrologic units, and of their water potential fields. The study area of this investigation is restricted to that part of Yucca Mountain that immediately overlies and is within the boundaries of the perimeter drift of a US Department of Energy proposed mined, geologic, high-level radioactive-waste repository. Vertically, the study area extends from near the surface of Yucca Mountain to the underlying water table, about 500 to 750 meters below the ground surface. The average distance between the proposed repository and the underlying water table is about 205 meters.

Book The Hydrogeologic Character of the Lower Tuff Confining Unit and the Oak Springs Butte Confining Unit in the Tuff Pile Area of Central Yucca Flat

Download or read book The Hydrogeologic Character of the Lower Tuff Confining Unit and the Oak Springs Butte Confining Unit in the Tuff Pile Area of Central Yucca Flat written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The lower tuff confining unit (LTCU) in the Yucca Flat Corrective Action Unit (CAU) consists of a monotonous sequence of pervasively zeolitized volcanic tuff (i.e., mostly bedded with lesser nonwelded to poorly welded tuff; not fractured) (Bechtel Nevada, 2006). The LTCU is an important confining unit beneath Yucca Flat because it separates the alluvial and volcanic aquifers, where many underground nuclear tests were conducted, from the regional lower carbonate aquifer. Recent sub-CAU-scale modeling by Los Alamos National Laboratory in the Tuff Pile area of Yucca Flat (Boryta, et al., in review) includes postulated low-porosity, high-permeability zones (i.e., fractured welded-tuff aquifers) within the LTCU. This scenario indicates that such postulated low-porosity, high-permeability zones could provide fast-path lateral conduits to faults, and eventually to the lower carbonate aquifer. A fractured and faulted lower carbonate aquifer is postulated to provide a flow path(s) for underground test-derived contaminants to potential offsite receptors. The ramifications of such a scenario are obvious for groundwater flow and contaminant migration beneath Yucca Flat. This paper describes the reasoning for not including postulated low-porosity, high-permeability zones within the LTCU in the Tuff Pile area or within the LTCU in the Yucca Flat CAU-scale model. Both observational and analytical data clearly indicate that the LTCU in the Tuff Pile area consists of pervasively zeolitic, nonwelded to poorly welded tuffs that are classified as tuff confining units (i.e., high-porosity, low-permeability). The position regarding the LTCU in the Tuff Pile area is summarized as follows: The LTCU in the Tuff Pile area consists of a monotonous sequence of predominantly zeolitic nonwelded to poorly welded tuffs, and thus is accurately characterized hydrogeologically as a tuff confining unit (aquitard) in the Yucca Flat-Climax Mine hydrostratigraphic framework model (Bechtel Nevada, 2006). No welded-tuff (or lava-flow aquifers), referred to as low-porosity, high-permeability zones in Boryta et al. (in review), are present within the LTCU in the Tuff Pile area. Fractures within the LTCU are poorly developed, a characteristic of zeolitic tuffs; and fracture distributions are independent of stratigraphic and lithologic units (Prothro, 2008). Groundwater flow and radionuclide transport will not be affected by laterally extensive zones of significantly higher permeability within the LTCU in the Tuff Pile area. Although not the primary focus of this report, the hydrogeologic character of the Oak Spring Butte confining unit (OSBCU), located directly below the LTCU, is also discussed. The OSBCU is lithologically more diverse, and does include nonwelded to partially welded ash-flow tuffs. However, these older ash-flow tuffs are poorly welded and altered (zeolitic to quartzofeldspathic), and consequently, would tend to have properties similar to a tuff confining unit rather than a welded-tuff aquifer.

Book High angle Faults in the Basement of Yucca Flat Nevada Test Site Nevada Based on Analysis of a Constrained Gravity Inversion Surface

Download or read book High angle Faults in the Basement of Yucca Flat Nevada Test Site Nevada Based on Analysis of a Constrained Gravity Inversion Surface written by and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Using a model of the topographic subsurface derived from drill hole and gravity inversion analysis of the basement rocks in Yucca Flat, Nevada Test Site (NTS), Nevada, a fault map and digital fault dataset were constructed based on offsets of the basement surface. Because these faults are, in large part, not present at the surface, they are interpreted to be inactive faults, older than the alluvial basin fill.