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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A trade-off between model resolution and variance with selected Rayleigh-wave data
Inversion of multimode surface-wave data is of increasing interest in the near-surface geophysics community. For a given near-surface geophysical problem, it is essential to understand how well the data, calculated according to a layered-earth model, might match the observed data. A data-resolution matrix is a function of the data kernel (determined by a geophysical model and a priori information
Authors
J. Xia, R. D. Miller, Y. Xu
Advances in quantitative elemental analyses by laser ablation ICP-MS
[No abstract available]
Authors
A.E. Koenig
Age, distribution, and formation of late cenozoic paleovalleys of the lower Colorado River and their relation to river aggradation and degradation
Distinctive far-traveled fluvial sediment of the lower Colorado River fills 20 paleo-valleys now stranded by the river downstream of Grand Canyon as it crosses the Basin and Range Province. These sediments resulted from two or more aggradational epi sodes in Pliocene and Pleistocene times following initial incision during the early Pliocene. A review of the stratigraphic evidence of major swings i
Authors
K. A. Howard, S.C. Lundstrom, D.V. Malmon, S.J. Hook
Agriculture-related trends in groundwater quality of the glacial deposits aquifer, central Wisconsin
Measuring and understanding trends in groundwater quality is necessary for determining whether changes in land-management practices have an effect on groundwater quality. This paper describes an approach that was used to measure and understand trends using data from two groundwater studies conducted in central Wisconsin as part of the USGS NAWQA program. One of the key components of this approach,
Authors
D. A. Saad
ALLTEM UXO detection and discrimination
ALLTEM is a multi-axis electromagnetic induction system designed for unexploded ordnance (UXO) applications. It uses a continuous triangle-wave excitation and provides good late-time signal-to-noise ratio (SNR) especially for ferrous targets. Multi-axis transmitter (Tx) and receiver (Rx) systems such as ALLTEM provide a richer data set from which to invert for the target parameters required to dis
Authors
T.H. Asch, D.L. Wright, C.W. Moulton, T.P. Irons, M.N. Nabighian
An evaluation of the evolution of the latest miocene to earliest pliocene bouse lake system in the lower Colorado river valley, southwestern USA
The upper Miocene to lower Pliocene Bouse Formation in the lower Colorado River trough of the American Southwest was deposited in three basins - from north to south, the Mohave, Havasu, and Blythe Basins - that were formed by extensional fault ing in the early to middle Miocene. Fossils of marine, brackish, and freshwater organ isms in the Bouse Formation have been interpreted to indicate an estua
Authors
J. E. Spencer, P. A. Pearthree, P.K. House
An illustrated landslide handbook for developing nations
As landslides continue to be a hazard that account for large numbers of human and animal casualties, property loss, and infrastructure damage, as well as impacts on the natural environment, it is incumbent on developed nations that resources be allocated to educate affected populations in less developed nations, and provide them with tools to effectively manage this hazard. Given that the engineer
Authors
Lynn M. Highland, Peter Bobrowsky
Application of high-resolution linear Radon transform for Rayleigh-wave dispersive energy imaging and mode separating
Multichannel Analysis of Surface Waves (MASW) analysis is an efficient tool to obtain the vertical shear-wave profile. One of the key steps in the MASW method is to generate an image of dispersive energy in the frequency-velocity domain, so dispersion curves can be determined by picking peaks of dispersion energy. In this paper, we image Rayleigh-wave dispersive energy and separate multimodes from
Authors
Y. Luo, J. Xia, R. D. Miller, J. Liu, Y. Xu, Q. Liu
Application of MODFLOW’s farm process to California’s Central Valley
Historically, California’s Central Valley has been one of the most productive agricultural regions in the world. The Central Valley also is rapidly becoming an important area for California’s expanding urban population. During 1980–2007, the population nearly doubled in the Central Valley, increasing the competition for water. Because of the importance of ground water in the Central Valley, the U.
Authors
Claudia C. Faunt, Randall T. Hanson, Wolfgang Schmid, Kenneth Belitz
Assessment of 2006 and 2007 drought patterns in the vegetation drought response index across Nebraska
The Vegetation Drought Response Index (VegDRI) is a hybrid geospatial drought indicator and monitoring tool that provides timely drought severity information with relatively higher spatial resolution (1-km2) than the traditional drought monitoring maps. The VegDRI model integrates climate-based drought index data, satellite-based vegetation index information, and several biophysical parameters. Du
Authors
Jesslyn F. Brown, Brian D. Wardlow, Md Shahriar Pervez, Tsegaye Tadesse
Browse evaluation of tall shrubs based on direct measurement of a management objective
The monitoring of Geyer willow was based on the following management objective: Browsing will prevent fewer than 50 percent of Geyer willow shrubs from growing taller than 3 m . Three questions were addressed: (1) Is browsing a potential factor? (2) If so, can young plants grow taller than 3 meters? (3) If not, is browsing the dominant factor? All shrubs were intensely browsed. With a post-browsin
Authors
R.B. Keigley, M.R. Frisina
Calibration of GOES-derived solar radiation data using a distributed network of surface measurements in Florida, USA
Solar radiation data are critically important for the estimation of evapotranspiration. Analysis of visible-channel data derived from Geostationary Operational Environmental Satellites (GOES) using radiative transfer modeling has been used to produce spatially- and temporally-distributed datasets of solar radiation. An extensive network of (pyranometer) surface measurements of solar radiation in t
Authors
David M. Sumner, Chandra S. Pathak, John R. Mecikalski, Simon J. Paech, Qinglong Wu, Taiye Sangoyomi