Conference Papers
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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 two-phase debris-flow model that includes coupled evolution of volume fractions, granular dilatancy, and pore-fluid pressure
Pore-fluid pressure plays a crucial role in debris flows because it counteracts normal stresses at grain contacts and thereby reduces intergranular friction. Pore-pressure feedback accompanying debris deformation is particularly important during the onset of debrisflow motion, when it can dramatically influence the balance of forces governing downslope acceleration. We consider further effects of
Authors
David L. George, Richard M. Iverson
Observations of mass fractionation of noble gases in synthetic methane hydrate
As a consequence of contemporary or longer term (since 15 ka) climate warming, gas hydrates in some settings are presently dissociating and releasing methane and other gases to the oceanatmosphere system. A key challenge in assessing the susceptibility of gas hydrates to warming climate is the lack of a technique able to distinguish between methane recently released from gas hydrates and methane e
Authors
Andrew G. Hunt, John W. Pohlman, Laura A. Stern, Carolyn D. Ruppel, Richard J. Moscati, Gary P. Landis, John C. Pinkston
Decoupled application of the integrated hydrologic model, GSFLOW, to estimate agricultural irrigation in the Santa Rosa Plain, California
No abstract available.
Authors
Joseph A. Hevesi, Linda R. Woolfenden, Richard G. Niswonger, R. Steven Regan, Tracy Nishikawa
Effect of the difference between water-table elevation and hydraulic head on simulation of unconfined aquifers using MODFLOW
No abstract available.
Authors
Alden M. Provost, Christian D. Langevin
Distribution of total mercury (THg) in California sea lions (Zalophus californianus) and their parasitic fauna
No abstract available.
Authors
A.K. McGrew, T. M. O'Hara, F. Gulland, W. Van Bonn, Craig A. Stricker, L.R. Ballweber
Process-based model predictions of hurricane induced morphodynamic change on low-lying barrier islands
Using Delft3D, a Chandeleur Island model was constructed to examine the sediment-transport patterns and morphodynamic change caused by Hurricane Katrina and similar storm events. The model setup included a coarse Gulf of Mexico domain and a nested finer-resolution Chandeleur Island domain. The finer-resolution domain resolved morphodynamic processes driven by storms and tides. A sensitivity analys
Authors
Nathaniel G. Plant, David M. Thompson, Edwin Elias
Planned updates and refinements to the Central Valley hydrologic model with an emphasis on improving the simulation of land subsidence in the San Joaquin Valley
California's Central Valley has been one of the most productive agricultural regions in the world for more than 50 years. To better understand the groundwater availability in the valley, the U.S. Geological Survey (USGS) developed the Central Valley hydrologic model (CVHM). Because of recent water-level declines and renewed subsidence, the CVHM is being updated to better simulate the geohydrologic
Authors
Claudia C. Faunt, Randall T. Hanson, Peter Martin, Wolfgang Schmid
The North American iron ore industry: A decade into the 21st century
During the 20th century, the iron ore mining industries of Canada and the United States passed through periods of transformation. The beginning of the 21st century has seen another period of transformation, with the failure of a number of steel companies and with consolidation of control within the North American iron ore industry. Canadian and United States iron ore production and the market cont
Authors
John D. Jorgenson, Andrés Pérez-Parada
Well log characterization of natural gas hydrates
In the last 25 years we have seen significant advancements in the use of downhole well logging tools to acquire detailed information on the occurrence of gas hydrate in nature: From an early start of using wireline electrical resistivity and acoustic logs to identify gas hydrate occurrences in wells drilled in Arctic permafrost environments to today where wireline and advanced logging-while-drilli
Authors
Timothy S. Collett, Myung W. Lee
Does littoral sand bypass the head of Mugu Submarine Canyon? - a modeling study
A newly developed sand-tracer code for the process-based model Delft3D (Deltares, The Netherlands) was used to simulate the littoral transport near the head of the Mugu Submarine Canyon in California, USA. For westerly swells, which account for more than 90% of the wave conditions in the region, the sand tracers in the downcoast littoral drift were unable to bypass the canyon head. A flow converge
Authors
Jingping Xu, Edwin Elias, Nicole Kinsman
Geologic controls on sediment distribution and transport pathways around the Chandeleur Islands, LA., USA
Geophysical surveys around the Chandeleur Islands provide the necessary data to map the thickness and distribution of the Holocene deposit associated with this barrier island system. This system rests uncomformably on St. Bernard Delta deposits of the Mississippi Delta plain and is thinnest under the central part of the island chain and thickest at the northern and southern ends. The zone of diver
Authors
David Twichell, Elizabeth A. Pendleton, Wayne Baldwin, James Flocks, Michael Miner, Mark Kulp
Hurricanes, sea level rise, and coastal change
Sixteen hurricanes have made landfall along the U.S. east and Gulf coasts over the past decade. For most of these storms, the USGS with our partners in NASA and the U.S. Army Corps of Engineers have flown before and after lidar missions to detect changes in beaches and dunes. The most dramatic changes occurred when the coasts were completely submerged in an inundation regime. Where this occurred l
Authors
Asbury H. Sallenger,