Conference Papers
Science Quality and Integrity
The USGS provides unbiased, objective, and impartial scientific information upon which our audiences, including resource managers, planners, and other entities, rely.
The USGS provides unbiased, objective, and impartial scientific information upon which our audiences, including resource managers, planners, and other entities, rely.
Browse almost 5,000 conference papers authored by our scientists and refine search by topic, location, year, and advanced search.
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Analysis of current-use pesticides in aquatic and terrestrial organisms collected throughout California, USA
A wide variety of pesticides are applied concurrently in agricultural and urban areas and transported off site dissolved in water and bound to sediments. But the exposure of aquatic and terrestrial organisms to current-use pesticides and the resulting effects are not well understood. One approach is to directly analyze tissue concentrations of contaminants. The overall objective of this study was
Authors
Kelly L. Smalling, Kathyrn M. Kuivila
Anomalously low strength of serpentinite sheared against granite and implications for creep on the Hayward and Calaveras Faults
Serpentinized ophiolitic rocks are juxtaposed against quartzofeldspathic rocks at depth across considerable portions of the Hayward and Calaveras Faults. The marked compositional contrast between these rock types may contribute to fault creep that has been observed along these faults. To investigate this possibility, we are conducting hydrothermal shearing experiments to look for changes in fricti
Authors
Diane E. Moore, David A. Lockner, David A. Ponce
Application of the control volume mixed finite element method to a triangular discretization
A control volume mixed finite element scheme for a triangular discretization of a 2-D domain is presented; several control-volume scenarios for use with the scheme are explored.
Authors
R.L. Naff
Archiving strategy for USGS EROS center and our future direction
The U. S. Geological Survey's Earth Resources Observation and Science Center has the responsibility to acquire, manage, and preserve our Nation's land observations. These records are obtained primarily from airplanes and satellites dating back to the 1930s. The ability to compare landscapes from the past with current information enables change analysis at local and global scales. With new observat
Authors
John Faundeen
Are modern geothermal waters in northwest Nevada forming epithermal gold deposits?
Hydrothermal systems currently are active near some gold deposits in northwestern Nevada. Possible links of these modern systems to gold mineralization were evaluated by chemically and isotopically analyzing water samples from the Brady, Dixie Valley, Humboldt House, San Emidio-Empire, Soda Lake, and Wabuska geothermal areas. In addition, quartz veins from Humboldt House and the adjacent Florida C
Authors
George N. Breit, Andrew G. Hunt, Ruth E. Wolf, Alan E. Koenig, Richard Fifarek, Mark F. Coolbaugh
Brine delineation and monitoring with electrical resistivity tomography and electromagnetic borehole logging at the Fort Knox well field near West Point, Kentucky
The potable water system at Fort Knox is threatened by brine contamination from improperly abandoned natural gas exploration wells. The Fort Knox well field is located near the town of West Point, Kentucky, in the flood plain of the Ohio River. At the site, unconsolidated sediments approximately 30 – 40 m thick, overlie shale and porous limestone. Brine is believed to flow vertically from the unde
Authors
Rory Henderson, Michael D. Unthank, Douglas D. Zettwoch, John W. Lane
Calibration and filtering strategies for frequency domain electromagnetic data
echniques for processing frequency-domain electromagnetic (FDEM) data that address systematic instrument errors and random noise are presented, improving the ability to invert these data for meaningful earth models that can be quantitatively interpreted. A least-squares calibration method, originally developed for airborne electromagnetic datasets, is implemented for a ground-based survey in order
Authors
Burke J. Minsley, Bruce D. Smith, Richard Hammack, James I. Sams, Garret Veloski
Changes in the North American ferroalloys industry structure and trends in the industry during the past 20 years
This analysis of changes in the North American (Canada, Mexico, and the United States) ferroalloys industry between 1987 and 2007 includes the locations and types of ferroalloy plants in North America and the changes in production, imports, exports, pricing, and the structure of ownership since 1987, which was just prior to the implementation of the North American Free Trade Agreement. Significant
Authors
J.R. Didaleusky, J.D. Jorgenson, L.A. Corathers, M.D. Fenton, P.H. Kuck, J.F. Papp, D.E. Polyak, Kim B. Shedd
Characterizing wet slab and glide slab avalanche occurrence along the Going-to-the-Sun Road, Glacier National Park, Montana, USA
Wet slab and glide slab snow avalanches are dangerous and yet can be particularly difficult to predict. Both wet slab and glide slab avalanches are thought to depend upon free water moving through the snowpack but are driven by different processes. In Glacier National Park, Montana, both types of avalanches can occur in the same year and affect the Going-to-the-Sun Road (GTSR). Both wet slab and g
Authors
Erich H. Peitzsch, Jordy Hendrikx, Daniel B. Fagre, Blase Reardon
Colloidal and physical transport textures exhibited by electrum and naumannite in bonanza epithermal veins from western USA, and their significance
It is reasonably clear that disequilibrium or “far-from equilibrium” conditions lead to the formation of silica colloids and their deposition in many epithermal deposits. This implies ore-forming solutions had elevated concentrations of dissolved silica, well in excess of amorphous silica saturation. We have previously demonstrated that such colloidal silica particles were deposited in epithermal
Authors
James A. Saunders, Peter G. Vikre, Derick L. Unger, Lee Beasley
Comparison of sap flux, moisture flux tower and MODIS enhanced vegetation index methods for estimating riparian evapotranspiration
Riparian evapotranspiration (ET) was measured on a salt cedar (Tamarix spp.) dominated river terrace on the Lower Colorado River from 2007 to 2009 using tissue-heat-balance sap flux sensors at six sites representing very dense, medium dense, and sparse stands of plants. Salt cedar ET varied markedly across sites, and sap flux sensors showed that plants were subject to various degrees of stress, de
Authors
Pamela L. Nagler, Edward P. Glenn, Kiyomi Morino
Computational modeling of bedform evolution in rivers with implications for predictions of flood stage and bed evolution
Uncertainties in flood stage prediction and bed evolution in rivers are frequently associated with the evolution of bedforms over a hydrograph. For the case of flood prediction, the evolution of the bedforms may alter the effective bed roughness, so predictions of stage and velocity based on assuming bedforms retain the same size and shape over a hydrograph will be
incorrect. These same effects w
Authors
Jonathan M. Nelson, Yasuyuki Shimizu, Sanjay Giri, Richard R. McDonald