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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Fracture in Westerly granite under AE feedback and constant strain rate loading: Nucleation, quasi-static propagation, and the transition to unstable fracture propagation
New observations of fracture nucleation are presented from three triaxial compression experiments on intact samples of Westerly granite, using Acoustic Emission (AE) monitoring. By conducting the tests under different loading conditions, the fracture process is demonstrated for quasi-static fracture (under AE Feedback load), a slowly developing unstable fracture (loaded at a 'slow' constant strain
Authors
B.D. Thompson, R.P. Young, D. A. Lockner
Future for polar bears in a declining sea ice environment: What do we know?
During an April 22, 2006, interview on the CBC radio program “The House,” Tim Flannery, author of the recent book “The Weathermakers,” stated, “Projections of the polar bear specialists are that by about 2030, around that date, the species will be extinct because of global warming induced changes in the Arctic sea ice.” That statement was followed on May 4th by quotations in the Toronto Globe and
Authors
Steven C. Amstrup
Gaussian-based filters for detecting Martian dust devils
The ability to automatically detect dust devils in the Martian atmosphere from orbital imagery is becoming important both for scientific studies of the planet and for the planning of future robotic and manned missions. This paper describes our approach for the unsupervised detection of dust devils and the preliminary results achieved to date. The algorithm centers upon the use of a filter construc
Authors
F. Yang, P.A. Mlsna, P. Geissler
Geochronology and tectonic significance of Middle Proterozoic granitic orthogneiss, North Qaidam HP/UHP terrane, Western China
Amphibolite-facies para- and orthogneisses near Dulan, in the southeast part of the North Qaidam terrane, enclose minor ultra-high pressure (UHP) eclogite and peridotite. Field relations and coesite inclusions in zircons from paragneiss suggest that felsic, mafic, and ultramafic rocks all experienced UHP metamorphism and a common amphibolite-facies retrogression. Ion microprobe U-Pb and REE analys
Authors
C.G. Mattinson, J. L. Wooden, J. G. Liou, D.K. Bird, C.L. Wu
Geodetic antenna calibration test in the Antarctic environment
TransAntarctic Mountain DEFormation (TAMDEF) Monitoring Network is the NSF-sponsored OSU and USGS project, aimed at measuring crustal motion in the Transantarctic Mountains of Victoria Land using GPS carrier phase measurements. Station monumentation, antenna mounts, antenna types, and data processing strategies were optimized to achieve mm-level estimates for the rates of motion. These data contri
Authors
A. Grejner-Brzezinska, E. Vazquez, L. Hothem
Geologic impacts of the 2004 Indian ocean tsunami on Indonesia, Sri Lanka, and the Maldives
The December 26, 2004 Indian Ocean tsunami was generated by a large submarine earthquake (magnitude ???9.1) with an epicenter located under the seafloor in the eastern Indian Ocean near northern Sumatra, Indonesia. The resulting tsunami was measured globally and had significant geologic impacts throughout the Indian Ocean basin. Observations of tsunami impacts, such as morphologic change, sediment
Authors
B. M. Richmond, B. E. Jaffe, G. Gelfenbaum, R.A. Morton
Geophysical evaluation of the Success Dam foundation, Porterville, California
Success Dam is a zonedearth fill embankment located near Porterville, CA. Studies of Success Dam by the recent Dam Safety Assurance Program (DSAP) have demonstrated the potential for seismic instability and large deformation of the dam due to relatively low levels of earthquake shaking. The U.S. Army Corps of Engineers conducted several phases of investigations to determine the properties of the d
Authors
L. E. Hunter, M.H. Powers, S. Haines, T. Asch, B.L. Burton, D.C. Serafini
Ground-water surface-water interactions and long-term change in riverine riparian vegetation in the southwestern United States
Riverine riparian vegetation has changed throughout the southwestern United States, prompting concern about losses of habitat and biodiversity. Woody riparian vegetation grows in a variety of geomorphic settings ranging from bedrock-lined channels to perennial streams crossing deep alluvium and is dependent on interaction between ground-water and surface-water resources. Historically, few reaches
Authors
R. H. Webb, S. A. Leake
Groundwater-supported evapotranspiration within glaciated watersheds under conditions of climate change
This paper analyzes the effects of geology and geomorphology on surface-water/-groundwater interactions, evapotranspiration, and recharge under conditions of long-term climatic change. Our analysis uses hydrologic data from the glaciated Crow Wing watershed in central Minnesota, USA, combined with a hydrologic model of transient coupled unsaturated/saturated flow (HYDRAT2D). Analysis of historical
Authors
D. Cohen, M. Person, R. Daannen, S. Locke, D. Dahlstrom, V. Zabielski, T. C. Winter, D. O. Rosenberry, H. Wright, E. Ito, J.L. Nieber, W.J. Gutowski
Groundwater-surface water interactions in wetlands for integrated water resources management
[No abstract available]
Authors
P. Schot, T. Winter
Guideline for assessing the performance of electric power systems in natural hazard and human threat events
Electric power utilities are familiar with and skilled in preparing for and responding to almost-routine natural hazard events such as strong wind and ice storms and seasonal floods, as well as intentional human acts such as vandalism. Recent extreme weather (hurricanes Katrina and Rita), extremely destructive international earthquakes (in Sumatra and Pakistan), and nation-wide concerns regarding
Authors
W.U. Savage, S. P. Nishenko, D.G. Honegger, L. Kempner
Habitat preferences and intraspecific competition in black-footed ferrets
We used radio-telemetry data (28,560 positional fixes) collected on 153 black-footed ferrets (Mustela nigripes) to (1) reexamine the assumed obligate relationship of these ferrets to prairie dogs (Cynomys spp.), (2) investigate habitat preferences of ferrets at a small scale (1 year (P = 0.048). Also, preference was stronger for wild-born young ferrets than for young captive-born ferrets released
Authors
Dean E. Biggins, Jerry L. Godbey, Marc R. Matchett, Travis M. Livieri