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Bedrock geologic map of the Yucca Mountain area, Nye County, Nevada

Description: Yucca Mountain, Nye County, Nevada, has been identified as a potential site for underground storage of high-level radioactive nuclear waste. Detailed bedrock geologic maps form an integral part of the site characterization program by providing the fundamental framework for research into the geologic hazards and hydrologic behavior of the mountain. This bedrock geologic map provides the geologic framework and structural setting for the area in and adjacent to the site of the potential repository. The study area comprises the northern and central parts of Yucca Mountain, located on the southern flank of the Timber Mountain-Oasis Valley caldera complex, which was the source for many of the volcanic units in the area. The Timber Mountain-Oasis Valley caldera complex is part of the Miocene southwestern Nevada volcanic field, which is within the Walker Lane belt. This tectonic belt is a northwest-striking megastructure lying between the more active Inyo-Mono and Basin-and-Range subsections o f the southwestern Great Basin.
Date: November 1, 1998
Creator: Day, W.C.; Potter, C.J.; Sweetkind, D.S.; Fridrich, C.J.; Dickerson, R.P.; San Juan, C.A. et al.
Partner: UNT Libraries Government Documents Department

Status report of propagation models: Middle East and North Africa (S5.3)

Description: An improved understanding of the influence that tectonic structure has on regional seismic phases is needed to improve the current performance of regional discriminants and their transportability to the Middle East and North Africa. In the case that the crustal structure can be approximated by a flat layered laterally invariant medium, layer-cake reflectivity modeling can be used to obtain an accurate representation of regional phases. However, a laterally heterogeneous crust is just as common as a layered cake structure and in this case large variations in regional phase amplitudes are not uncommon. For instance, it has been shown that rough surface topography and undulations in the Moho can cause the transfer of energy between various surface wave modes and between surface waves and body waves greatly increasing the potential variability of seismic phases. Larger scale structure such as thickening or thinning of the crust can also greatly affect phase propagation. In some instances, changes between different tectonic regions such as that which occurs at a continental-oceanic boundary can completely block phases such as Lg rendering certain discriminants useless. In addition to structure along the path, lateral structure and free surface topography near the source and receiver can cause complex scattering effects with strong directional, frequency, and near-field effects. Given that the Middle East and North Africa cross many different tectonic boundaries, the authors are using numerical propagation models to understand how the relevant tectonic features affect the propagation of primary discriminant phases.
Date: November 1, 1995
Creator: Schultz, C.A.; Patton, H.J. & Goldstein, P.
Partner: UNT Libraries Government Documents Department

Lithospheric processes

Description: This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The main objective was to improve understanding of the origin and evolution of the Earth`s lithosphere by studying selected processes, such as deformation and magmatic intrusion during crustal extension, formation and extraction of mantle melts, fluid transport of heat and mass, and surface processes that respond to deep-seated events. Additional objectives were to promote and develop innovative techniques and to support relevant educational endeavors. Seismic studies suggest that underplating of crust by mantle melts is an important crustal-growth mechanism, that low-angle faults can be seismogenic, and that shear deformation creates mantle anisotropy near plate boundaries. Results of geochemical work determined that magmas from oceanic intraplate islands are derived from a uniform depth in the upper mantle, whereas melts erupted at mid-ocean ridges are mixed from a range of depths. The authors have determined the extent and style of fluid infiltration and trace-element distribution in natural magmatic systems, and, finally, investigated {sup 21}Ne as a tool for dating of surficial materials.
Date: November 1, 1997
Creator: Baldridge, W.S.; Wohletz, K. & Fehler, M.C.
Partner: UNT Libraries Government Documents Department

Bedrock geologic map of the central block area, Yucca Mountain, Nye County, Nevada

Description: Bedrock geologic maps form the foundation for investigations that characterize and assess the viability of the potential high-level radioactive waste repository at Yucca Mountain, Nevada. This study was funded by the US Department of Energy Yucca Mountain Project to provide a detailed (1:6,000-scale) bedrock geologic map for the area within and adjacent to the potential repository area at Yucca Mountain, Nye County, Nevada. Prior to this study, the 1:12,000-scale map of Scott and Bon, (1984) was the primary source of bedrock geologic data for the Yucca Mountain Project. However, targeted detailed mapping within the central block at Yucca Mountain revealed structural complexities along some of the intrablock faults that were not evident at 1:12,000 (Scott and Bonk, 1984). As a result, this study was undertaken to define the character and extent of the dominant structural features in the vicinity of the potential repository. In addition to structural considerations, ongoing subsurface excavation and geologic mapping within the exploratory Studies Facility (ESF), development of a three-dimensional-framework geologic model, and borehole investigations required use of a constituent stratigraphic system to facilitate surface to underground comparisons. The map units depicted in this report correspond as closely as possible to the proposed stratigraphic nomenclature by Buesch and others (1996), as described here.
Date: November 1, 1998
Creator: Day, W.C.; Potter, C.J.; Sweetkind, D.S.; Dickerson, R.P. & San Juan, C.A.
Partner: UNT Libraries Government Documents Department

Unpublished letter from US Geological Survey Scientists to the editor of the New York Times Magazine regarding William J. Broads` November 18, 1990 article on Yucca Mountain

Description: This letter documents objections of a group of US Geological Survey Scientists to an article appearing November 18, 1990 in New York Times Magazine. The article was written by William J. Broad and dealt with a hypothesis of Jerry S. Szymanski. The letter addressed areas of concern; including hydrology, geology, tectonics, and the integrity of the scientists and their conclusions. (SM)
Date: November 28, 1990
Creator: Dudley, W.W. Jr.; Buono, A.; Carr, M.D.; Downey, J.S.; Ervin, E.M.; Fox, K.F. Jr. et al.
Partner: UNT Libraries Government Documents Department

Geothermal reservoir assessment case study: Northern Dixie Valley, Nevada

Description: Two 1500 foot temperature gradient holes and two deep exploratory wells were drilled and tested. Hydrologic-hydrochemical, shallow temperature survey, structural-tectonic, petrologic alteration, and solid-sample geochemistry studies were completed. Eighteen miles of high resolution reflection seismic data were gathered over the area. The study indicates that a geothermal regime with temperatures greater than 400/sup 0/F may exist at a depth of approximately 7500' to 10,000' over an area more than ten miles in length.
Date: November 1, 1980
Creator: Denton, J.M.; Bell, E.J. & Jodry, R.L.
Partner: UNT Libraries Government Documents Department

Structural fabric and in-situ stress analyses of the Roosevelt Hot Springs KGRA

Description: The Roosevelt Hot Springs Known Geothermal Resource Area (KGRA) is a hot-water dominated system in fractured plutonic and metamorphic rock. A principal purpose of this study was to determine the geometry and origin of fractures as an aid to developing a structural model for the reservoir. The results may also be useful for the design of hydrofracture experiments at the Roosevelt KGRA. Three major normal fault trends are present in the Mineral Mountains. North-northeast trending faults, including the Opal Mound Fault, form the center of low electrical resistivity and high heat flow anomalies. Major east-west trending structures such as the Hot Springs Fault form structural boundaries for the geothermal reservoir. A set of northwest trending faults also occurs in the KGRA. Structural analysis was conducted by field mapping of joints, small shear zones, and dikes. Three major styles of fracturing have been identified.
Date: November 1, 1979
Creator: Yusas, M.R. & Bruhn, R.L.
Partner: UNT Libraries Government Documents Department

Bulletin of the Seismological Laboratory, January 1, 1975-December 31, 1979

Description: The determination of epicenters for earthquakes located in the western Great Basin, Nevada and eastern California, for the period 1975 to 1979 is summarized. The Laboratory attempts to identify and locate all earthquakes with M/sub L/ greater than about 2.5 in this region.
Date: November 1, 1980
Creator: Smith, G M & Ryall, F D
Partner: UNT Libraries Government Documents Department

Rocking and overturning response of rigid bodies to earthquake motions: a report of an analytical and experimental study on the rocking and overturning response of rigid blocks to simultaneous horizontal and vertical accelerations

Description: A fundamental study of the rocking and overturning response of massive concrete blocks (with relatively high aspect ratio) to simultaneous horizontal and vertical earthquake ground motions is presented. This problem occurs when large concrete blocks are used as radiation shields in particle accelerators or similar nuclear installations. The results of this study also offer insight into the response of the rigid bodies (such as are approximated by some electrical machinery and mechanical equipment) which are not anchored to the ground. The mathematical model used was based on the assumption of a constant coefficient of restitution. A computer program was written to predict the rocking and overturning behavior of rigid rectangular blocks under simultaneously applied horizontal and vertical ground accelerations. Using the computer program, the response of rigid blocks of various aspect ratios and sizes was studied under the accelerograms of various strong motion earthquakes.
Date: November 1, 1978
Creator: Aslam, M.; Godden, W.G. & Scalise, D.T.
Partner: UNT Libraries Government Documents Department

Seismic data catalog and associated graphical capabilities

Description: To facilitate the use of the enormous amount of earthquake data presently available, Pacific Northwest Laboratory (PNL) formed an extensive data base of compiled seismic data. PNL also developed many useful and unique computer techniques for analysis and display of the data. These techniques could be used in many areas of the United States to support nuclear waste management and other energy-related activities. Software associated with the data base includes programs for editing earthquake files; sorting files with respect to time, location, or magnitude; selecting data by use of various parameters; and merging files. These techniques allow the rapid formation of data files that are tailored to specific interests. The desired file may then be listed or displayed graphically by means of PNL's diversified graphic capability. From the data analysis software, an accurate and comprehensive earthquake catalog for the Pacific Northwest was created. This catalog was produced by merging data from many sources and includes microearthquake data. Duplicate events were eliminated, while all information available for a particular event was retained. Graphic displays can plot two- and three-dimensional epicenter or hypocenter information. Magnitude and/or depth information can be represented on two-dimensional plots by using color or symbol size. Plots can be produced using a variety of map projections and at a specified scale. This capability allows the use of any desired map as a base map for the display of earthquake data. Additional information such as rivers, coastlines, faults, and boundaries may also be included on the plots. Data may also be displayed using normal or two-dimensional histograms. 19 figures, 7 tables.
Date: November 1, 1979
Creator: Bishop, T.N.; Foote, H.P. & Blair, S.C.
Partner: UNT Libraries Government Documents Department

Center for Volcanic and Tectonic Studies, Department of Geoscience annual report, October 1, 1989--September 30, 1990

Description: This report summarizes our activities during the period October 1, 1989 to September 30, 1990. Our goal was to develop an understanding of late-Miocene and Pliocene volcanism in the Great Basin by studying Pliocene volcanoes in the vicinity of the proposed high-level nuclear waste repository at Yucca Mountain, Nevada. Field studies during this period concentrated on the Quaternary volcanoes in Crater Flat, Yucca Mountain, Fortification Hill, at Buckboard Mesa and Sleeping Butte, and in the Reveille Range. Also, a study was initiated on structurally disrupted basaltic rocks in the northern White Hills of Mohave County, Arizona. As well as progress reports of our work in Crater Flat, Fortification Hill and the Reveille Range, this paper also includes a summary of model that relates changing styles of Tertiary extension to changing magmatic compositions, and a summary of work being done in the White Hills, Arizona. In the Appendix, we include copies of published papers not previously incorporated in our monthly reports.
Date: November 1, 1990
Creator: Smith, E.I.
Partner: UNT Libraries Government Documents Department

Source characterization of selected North Caspian events from the relative excitation of regional phases. Final report

Description: Seismograms of seven recent events (presumed underground nuclear explosions) which occurred during 1976-1979 in the North Caspian Sea region of the western Soviet Kazakh are compared at regional distances for their relative source excitation characteristics. The body wave magnitude estimates of these events range from 5.1 to 6.0. The data consist of analog and digital records collected at stations ranging in instrumental sophistication from temporary sites with single component smoke drum capability to those of SRO, ASRO and array (ILPA) configurations with digitally recorded down-hole observations. The amplitude and frequency measurements of the analog seismograms for the first arrival and the peak amplitude of P coda as well as for the clear S wave signals recorded for different events at the same station are compared.
Date: November 1, 1981
Creator: Niazi, M.
Partner: UNT Libraries Government Documents Department

IGPP-LLNL 1998 annual report

Description: The Institute of Geophysics and Planetary Physics (IGPP) is a Multicampus Research Unit of the University of California (UC). IGPP was founded in 1946 at UC Los Angeles with a charter to further research in the earth and planetary sciences and related fields. The Institute now has branches at UC campuses in Los Angeles, San Diego, and Riverside, and at Los Alamos and Lawrence Livermore national laboratories. The University-wide IGPP has played an important role in establishing interdisciplinary research in the earth and planetary sciences. For example, IGPP was instrumental in founding the fields of physical oceanography and space physics, which at the time fell between the cracks of established university departments. Because of its multicampus orientation, IGPP has sponsored important interinstitutional consortia in the earth and planetary sciences. Each of the five branches has a somewhat different intellectual emphasis as a result of the interplay between strengths of campus departments and Laboratory programs. The IGPP branch at Lawrence Livermore National Laboratory (LLNL) was approved by the Regents of the University of California in 1982. IGPP-LLNL emphasizes research in tectonics, geochemistry, and astrophysics. It provides a venue for studying the fundamental aspects of these fields, thereby complementing LLNL programs that pursue applications of these disciplines in national security and energy research. IGPP-LLNL is directed by Charles Alcock and was originally organized into three centers: Geosciences, stressing seismology; High-Pressure Physics, stressing experiments using the two-stage light-gas gun at LLNL; and Astrophysics, stressing theoretical and computational astrophysics. In 1994, the activities of the Center for High-Pressure Physics were merged with those of the Center for Geosciences. The Center for Geosciences, headed by Frederick Ryerson, focuses on research in geophysics and geochemistry. The Astrophysics Research Center, headed by Kem Cook, provides a home for theoretical and observational astrophysics and serves as an interface ...
Date: November 19, 1999
Creator: Ryerson, Frederick J.; Cook, Kem H. & Tweed, Jan
Partner: UNT Libraries Government Documents Department

Surface-wave generation by underground nuclear explosions releasing tectonic strain

Description: Seismic surface-wave generation by underground nuclear explosions releasing tectonic strain is studied through a series of synthetic radiation-pattern calculations based on the earthquake-trigger model. From amplitude and phase radiation patterns for 20-s Rayleigh waves, inferences are made about effects on surface-wave magnitude, M/sub s/, and waveform character. The focus of this study is a comparison between two mechanisms of tectonic strain release: strike-slip motion on vertical faults and thrust motion on 45/sup 0/ dipping faults. The results of our calculations show that Rayleigh-wave amplitudes of the dip-slip model at F values between 0.75 and 1.5 are significantly lower than amplitudes of the strike-slip model or of the explosion source alone. This effect translates into M/sub s/ values about 0.5 units lower than M/sub s/ of the explosion alone. Waveform polarity reversals occur in two of four azimuthal quadrants for the strike-slip model and in all azimuths of the dip-slip-thrust model for F values above about 3. A cursory examination of waveforms from presumed explosions in eastern Kazakhstan suggests that releases of tectonic strain are accompanying the detonation of many of these explosions. Qualitatively, the observations seem to favor the dip-slip-thrust model, which, in the case of a few explosions, must have F values above 3.
Date: November 3, 1980
Creator: Patton, H.J.
Partner: UNT Libraries Government Documents Department

A Geochemical and Sedimentary Record of High Southern Latitude Holocene Climate Evolution from Lago Fagnano, Tierra del Fuego

Description: Situated at the southern margin of the hemispheric westerly wind belt and immediately north of the Antarctic Polar Frontal zone, Tierra del Fuego is well-positioned to monitor coupled changes in the ocean-atmosphere system of the high southern latitudes. Here we describe a Holocene paleoclimate record from sediment cores obtained from Lago Fagnano, a large lake in southern Tierra del Fuego at 55{sup o}S, to investigate past changes in climate related to these two important features of the global climate system. We use an AMS radiocarbon chronology for the last 8,000 years based on pollen concentrates, thereby avoiding contamination from bedrock-derived lignite. Our chronology is consistent with a tephrochronologic age date for deposits from the middle Holocene Volcan Hudson eruption. Combining bulk organic isotopic ({delta}{sup 13}C and {delta}{sup 15}N) and elemental (C and N) parameters with physical sediment properties allow us to better understand sediment provenance and transport mechanisms and to interpret Holocene climate and tectonic change during the last 8,000 years. Co-variability and long-term trends in C/N ratio, carbon accumulation rate, and magnetic susceptibility reflect an overall Holocene increase in the delivery of terrestrial organic and lithogenic material to the deep eastern basin. We attribute this variability to westerly wind-derived precipitation. Increased wind strength and precipitation in the late Holocene drives the Nothofagus forest eastward and enhances run-off and terrigenous inputs to the lake. Superimposed on the long-term trend are a series of abrupt 9 negative departures in C/N ratio, which constrain the presence of seismically-driven mass flow events in the record. We identify an increase in bulk {delta}{sup 13}C between 7,000 and 5,000 cal yr BP that we attribute to enhanced aquatic productivity driven by warmer summer temperatures. The Lago Fagnano {delta}{sup 13}C record shows similarities with Holocene records of sea surface temperature from the mid-latitude Chilean continental shelf ...
Date: November 19, 2010
Creator: Moy, C M; Dunbar, R B; Guilderson, T P; Waldmann, N; Mucciarone, D A; Recasens, C et al.
Partner: UNT Libraries Government Documents Department

Seismic studies in Austin-Pleasant Bayou and Cuero Prospects - a summary of research activities

Description: Studies based partly on pre-existing or recently acquired seimic data were designed to confirm or improve the geological interpretation and resource assessment of geopressure geothermal prospect areas in Texas. Other objectives were (1) to evaluate seismic signatures as indicators of lithologic properties, (2) to assist in projecting structural and stratigraphic information beyond the limits of well control, and (3) to investigate processing techniques that enhance data displays by improving signal-to-noise ratios and suppressing multiples in the deep objective section. Two prospect areas with contrasting structural styles and geologic histories were selected for detailed investigations of sedimentation and structural development using available electric logs and geophysical surveys. In the first area, near Cuero, De Witt County, Texas, new seismic data acquired for the study were supplemented both with lines donated for research purposes and with data purchased commercially. The second study area included the Austin Bayou Prospect, Brazoria County, Texas, where the Pleasant Bayou No. 2 well was drilled and completed in the Frio Formation.
Date: November 1, 1980
Creator: Morton, R.A.; Winker, C.D. & Garcia, D.A.
Partner: UNT Libraries Government Documents Department

Seismic exploration for shallow magma bodies in the vicinity of Socorro, New Mexico. Final report, January 1, 1977-December 31, 1977

Description: This report contains the following articles: Characteristics of Rio Grande rift in vicinity of Socorro, New Mexico, from geophysical studies; Exploration framework of the Socorro Geothermal Area, New Mexico; a study of Poisson's ratio in the upper crust in the Socorro, New Mexico, Area; and Microearthquake frequency attenuation of S phases in the Rio Grande rift near Socorro. (ACR)
Date: November 1, 1980
Creator: Sanford, A.R. & Schlue, J.
Partner: UNT Libraries Government Documents Department

Multi-Attribute Seismic/Rock Physics Approach to Characterizing Fractured Reservoirs

Description: Most current seismic methods to seismically characterize fractures in tight reservoirs depend on a few anisotropic wave propagation signatures that can arise from aligned fractures. While seismic anisotropy can be a powerful fracture diagnostic, a number of situations can lessen its usefulness or introduce interpretation ambiguities. Fortunately, laboratory and theoretical work in rock physics indicates that a much broader spectrum of fracture seismic signatures can occur, including a decrease in P- and S-wave velocities, a change in Poisson's ratio, an increase in velocity dispersion and wave attenuation, as well as well as indirect images of structural features that can control fracture occurrence. The goal of this project was to demonstrate a practical interpretation and integration strategy for detecting and characterizing natural fractures in rocks. The approach was to exploit as many sources of information as possible, and to use the principles of rock physics as the link among seismic, geologic, and log data. Since no single seismic attribute is a reliable fracture indicator in all situations, the focus was to develop a quantitative scheme for integrating the diverse sources of information. The integrated study incorporated three key elements: The first element was establishing prior constraints on fracture occurrence, based on laboratory data, previous field observations, and geologic patterns of fracturing. The geologic aspects include analysis of the stratigraphic, structural, and tectonic environments of the field sites. Field observations and geomechanical analysis indicates that fractures tend to occur in the more brittle facies, for example, in tight sands and carbonates. In contrast, strain in shale is more likely to be accommodated by ductile flow. Hence, prior knowledge of bed thickness and facies architecture, calibrated to outcrops, are powerful constraints on the interpreted fracture distribution. Another important constraint is that fracturing is likely to be more intense near faults--sometimes referred to as ...
Date: November 30, 2004
Creator: Mavko, Gary
Partner: UNT Libraries Government Documents Department

Geothermal energy: Geology, exploration, and developments. Part I

Description: Geology, exploration, and initial developments of significant geothermal areas of the world are summarized in this report which is divided into two parts. Part 1 is a review of the geological and explorational aspects of geothermal energy development; areas of potential development in the Western United States are also discussed. The most favorable geological environment for exploration and development of geothermal steam is characterized by recent normal faulting, volcanism, and high heat flow. Successful exploration for steam consists of coordinated multidisciplinary application of geological, geophysical, and geochemical knowledge and techniques. These are reviewed. California leads in known geothermal reserves and is followed by Nevada, Oregon, and New Mexico. Specific prospective areas in these 11 Western States are described.
Date: November 1, 1971
Creator: Grose, L. T.
Partner: UNT Libraries Government Documents Department

Earthquake damage to underground facilities

Description: The potential seismic risk for an underground nuclear waste repository will be one of the considerations in evaluating its ultimate location. However, the risk to subsurface facilities cannot be judged by applying intensity ratings derived from the surface effects of an earthquake. A literature review and analysis were performed to document the damage and non-damage due to earthquakes to underground facilities. Damage from earthquakes to tunnels, s, and wells and damage (rock bursts) from mining operations were investigated. Damage from documented nuclear events was also included in the study where applicable. There are very few data on damage in the subsurface due to earthquakes. This fact itself attests to the lessened effect of earthquakes in the subsurface because mines exist in areas where strong earthquakes have done extensive surface damage. More damage is reported in shallow tunnels near the surface than in deep mines. In mines and tunnels, large displacements occur primarily along pre-existing faults and fractures or at the surface entrance to these facilities.Data indicate vertical structures such as wells and shafts are less susceptible to damage than surface facilities. More analysis is required before seismic criteria can be formulated for the siting of a nuclear waste repository.
Date: November 1, 1978
Creator: Pratt, H.R. & Hustrulid, W.A. Stephenson, D.E.
Partner: UNT Libraries Government Documents Department


Description: The principal research effort for Year 1 of the project is data compilation and the determination of the tectonic and depositional histories of the North Louisiana Salt Basin. In the first three (3) to six (6) months of Year 1, the research focus is on data compilation and the remainder of the year the emphasis is on the tectonic and depositional histories of the basin. No major problems have been encountered to date, and the project is on schedule.
Date: November 11, 2003
Creator: Mancini, Ernest A.
Partner: UNT Libraries Government Documents Department

Characterize Framework for Igneous Activity at Yucca Mountain, Nevada

Description: The purpose of this Analysis/Model (AMR) report is twofold. (1) The first is to present a conceptual framework of igneous activity in the Yucca Mountain region (YMR) consistent with the volcanic and tectonic history of this region and the assessment of this history by experts who participated in the Probabilistic Volcanic Hazard Analysis (PVHA) (CRWMS M&O 1996). Conceptual models presented in the PVHA are summarized and extended in areas in which new information has been presented. Alternative conceptual models are discussed as well as their impact on probability models. The relationship between volcanic source zones defined in the PVHA and structural features of the YMR are described based on discussions in the PVHA and studies presented since the PVHA. (2) The second purpose of the AMR is to present probability calculations based on PVHA outputs. Probability distributions are presented for the length and orientation of volcanic dikes within the repository footprint and for the number of eruptive centers located within the repository footprint (conditional on the dike intersecting the repository). The probability of intersection of a basaltic dike within the repository footprint was calculated in the AMR ''Characterize Framework for Igneous Activity at Yucca Mountain, Nevada'' (CRWMS M&O 2000g) based on the repository footprint known as the Enhanced Design Alternative [EDA II, Design B (CRWMS M&O 1999a; Wilkins and Heath 1999)]. Then, the ''Site Recommendation Design Baseline'' (CRWMS M&O 2000a) initiated a change in the repository design, which is described in the ''Site Recommendation Subsurface Layout'' (CRWMS M&O 2000b). Consequently, the probability of intersection of a basaltic dike within the repository footprint has also been calculated for the current repository footprint, which is called the 70,000 Metric Tons of Uranium (MTU) No-Backfill Layout (CRWMS M&O 2000b). The calculations for both footprints are presented in this AMR. In addition, the probability ...
Date: November 6, 2000
Creator: Perry, F. & Youngs, B.
Partner: UNT Libraries Government Documents Department

Response to"Analysis of the Treatment, by the U.S. Department of Energy, of the FEP Hydrothermal Activity in the Yucca Mountain Performance Assessment" by Yuri Dublyansky

Description: This paper presents a rebuttal to Dublyansky (2007), which misrepresents technical issues associated with hydrothermal activity at the proposed Yucca Mountain nuclear waste repository and their importance to the long-term performance of the repository. In this paper, questions associated with hydrothermal activity are reviewed and the justification for exclusion of hydrothermal activity from performance assessment is presented. The hypothesis that hydrothermal upwelling into the present-day unsaturated zone has occurred at Yucca Mountain is refuted by the unambiguous evidence that secondary minerals and fluid inclusions in the unsaturated zone formed in an unsaturated environment from downward percolating meteoric waters. The thermal history at Yucca Mountain, inferred from fluid inclusion and isotopic data, is explained in terms of the tectonic extensional environment and associated silicic magmatism. The waning of tectonic extension over millions of years has led to the present-day heat flux in the Yucca Mountain region that is below average for the Great Basin. The long time scales of tectonic processes are such that any effects of a resumption of extension or silicic magmatism on hydrothermal activity at Yucca Mountain over the 10,000-year regulatory period would be negligible. The conclusion that hydrothermal activity was incorrectly excluded from performance assessment as asserted in Dublyansky (2007) is contradicted by the available technical and regulatory information.
Date: November 17, 2008
Creator: Houseworth, J.E. & Hardin, E.
Partner: UNT Libraries Government Documents Department