Population dynamics of tule elk at point Reyes National Seashore, California
J. A. Howell, G. C. Brooks, M. Semenoff-Irving, C. Greene
2002, Journal of Wildlife Management (66) 478-490
The presence of locally abundant wildlife raises questions about natural regulation and ecological consequences of overpopulation. We sought to establish precise information about population size, structure, and productivity to examine the role of natural regulation in a closed tule elk (Cervus elaphus nannodes) population at Point Reyes National Seashore, California,...
Ancient impact structures on modern continental shelves: The Chesapeake Bay, Montagnais, and Toms Canyon craters, Atlantic margin of North America
C. Wylie Poag, J. B. Plescia, P.C. Molzer
2002, Deep-Sea Research Part II: Topical Studies in Oceanography (49) 1081-1102
Three ancient impact craters (Chesapeake Bay - 35.7 Ma; Toms Canyon - 35.7 Ma; Montagnais - 51 Ma) and one multiring impact basin (Chicxulub - 65 Ma) are currently known to be buried beneath modern continental shelves. All occur on the passive Atlantic margin of North America in regions extensively...
Impact of sensor's point spread function on land cover characterization: Assessment and deconvolution
C. Huang, J.R.G. Townshend, S. Liang, S.N.V. Kalluri, R.S. DeFries
2002, Remote Sensing of Environment (80) 203-212
Measured and modeled point spread functions (PSF) of sensor systems indicate that a significant portion of the recorded signal of each pixel of a satellite image originates from outside the area represented by that pixel. This hinders the ability to derive surface information from satellite images on a per-pixel basis....
Evaluating remedial alternatives for an acid mine drainage stream: Application of a reactive transport model
R.L. Runkel, B. A. Kimball
2002, Environmental Science & Technology (36) 1093-1101
A reactive transport model based on one-dimensional transport and equilibrium chemistry is applied to synoptic data from an acid mine drainage stream. Model inputs include streamflow estimates based on tracer dilution, inflow chemistry based on synoptic sampling, and equilibrium constants describing acid/base, complexation, precipitation/dissolution, and sorption reactions....
Problems in evaluating regional and local trends in temperature: An example from eastern Colorado, USA
R.A. Pielke Sr., T. Stohlgren, L. Schell, W. Parton, N. Doesken, K. Redmond, J. Moeny, T. McKee, T.G.F. Kittel
2002, International Journal of Climatology (22) 421-434
We evaluated long-term trends in average maximum and minimum temperatures, threshold temperatures, and growing season in eastern Colorado, USA, to explore the potential shortcomings of many climate-change studies that either: (1) generalize regional patterns from single stations, single seasons, or a few parameters over short duration from averaging dissimilar stations:...
Variation in survivorship of a migratory songbird throughout its annual cycle
Sillett T. Scott, Richard T. Holmes
2002, Journal of Animal Ecology (71) 296-308
1. Demographic data from both breeding and non-breeding periods are needed to manage populations of migratory birds, many of which are declining in abundance and are of conservation concern. Although habitat associations, and to a lesser extent, reproductive biology, are known for many migratory species, few studies have measured survival...
Cripple Creek and other alkaline-related gold deposits in the Southern Rocky Mountains, USA: Influence of regional tectonics
Karen D. Kelley, Steve Ludington
2002, Mineralium Deposita (37) 38-60
Alkaline-related epithermal vein, breccia, disseminated, skarn, and porphyry gold deposits form a belt in the southern Rocky Mountains along the eastern edge of the North American Cordillera. Alkaline igneous rocks and associated hydrothermal deposits formed at two times. The first was during the Laramide orogeny (about 70–40 Ma), with deposits restricted...
Comments on baseline correction of digital strong-motion data: Examples from the 1999 Hector Mine, California, earthquake
D.M. Boore, C.D. Stephens, W. B. Joyner
2002, Bulletin of the Seismological Society of America (92) 1543-1560
Residual displacements for large earthquakes can sometimes be determined from recordings on modern digital instruments, but baseline offsets of unknown origin make it difficult in many cases to do so. To recover the residual displacement, we suggest tailoring a correction scheme by studying the character of the velocity obtained by...
Ancient and modern subduction zone contributions to the mantle sources of lavas from the Lassen region of California inferred from Lu-Hf isotopic systematics
L. E. Borg, Janne Blichert-Toft, Michael A. Clynne
2002, Journal of Petrology (43) 705-723
Hafnium isotopic compositions have been determined on a suite of calc-alkaline and high-alumina-olivine tholeiitic lavas from the Lassen region of California and are used, in conjunction with previously published mineralogical, geochemical, and isotopic data, to constrain their petrogenesis. Positive correlation between εHf values and geochemical indices of the modern subduction component...
234U/238U evidence for local recharge and patterns of groundwater flow in the vicinity of Yucca Mountain, Nevada, USA
J.B. Paces, K.R. Ludwig, Z. E. Peterman, L.A. Neymark
2002, Applied Geochemistry (17) 751-779
Uranium concentrations and 234U/238U ratios in saturated-zone and perched ground water were used to investigate hydrologic flow and downgradient dilution and dispersion in the vicinity of Yucca Mountain, a potential high-level radioactive waste disposal site. The U data were obtained by thermal ionization mass spectrometry on more than 280 samples...
Description of nests, eggs, and nestlings of the endangered nightingale reed-warbler on Saipan, Micronesia
Stephen M. Mosher, Steven G. Fancy
2002, The Wilson Bulletin (114) 1-10
We describe the first verified nests, eggs, and nestlings of the Nightingale Reed-Warbler (Acrocephalus luscinia), an endangered species endemic to the Mariana Islands, Micronesia. Nest composition, nest dimensions, and eggs were studied on the island of Saipan. Nests were located within three habitat types: upland introduced tangantangan (Leucaena...
Maturation and fecundity of a stock-enhanced population of striped bass in the Savannah River Estuary, U.S.A.
T.A. Will, T.R. Reinert, Cecil A. Jennings
2002, Journal of Fish Biology (60) 532-544
The striped bass Morone saxatilis population in the Savannah River (south-eastern U.S.A.) collapsed in the 1980s, and recent efforts to restore the population have resulted in increased catch-per-unit-effort (CPUE) of striped bass in the Savannah River Estuary (SRE). The abundance of eggs and larvae, however, remain well below historic levels....
Deformation associated with the 1997 eruption of Okmok volcano, Alaska
Dorte Mann, Jeffrey T. Freymueller, Z. Lu
2002, Journal of Geophysical Research B: Solid Earth (107) ETG 7-1-ETG 7-12
Okmok volcano, located on Umnak Island in the Aleutian chain, Alaska, is the most eruptive caldera system in North America in historic time. Its most recent eruption occurred in 1997. Synthetic aperture radar interferometry shows deflation of the caldera center of up to 140 cm during this time, preceded and...
Transport and fate of nitrate in a glacial outwash aquifer in relation to ground water age, land use practices, and redox processes
Larry J. Puckett, Timothy K. Cowdery
2002, Journal of Environmental Quality (31) 782-796
A combination of ground water modeling, chemical and dissolved gas analyses, and chlorofluorocarbon age dating of water was used to determine the relation between changes in agricultural practices, and NO−3 concentrations in ground water of a glacial outwash aquifer in west-central Minnesota. The results revealed a redox zonation throughout the saturated...
The 1999 Mw 7.1 Hector Mine, California, earthquake: A test of the stress shadow hypothesis?
R.A. Harris, R.W. Simpson
2002, Bulletin of the Seismological Society of America (92) 1497-1512
We test the stress shadow hypothesis for large earthquake interactions by examining the relationship between two large earthquakes that occurred in the Mojave Desert of southern California, the 1992 Mw 7.3 Landers and 1999 Mw 7.1 Hector Mine earthquakes. We want to determine if the 1999 Hector Mine earthquake occurred...
Diffusion model validation and interpretation of stable isotopes in river and lake ice
M.G. Ferrick, D.J. Calkins, N.M. Perron, J.H. Cragin, C. Kendall
2002, Hydrological Processes (16) 851-872
The stable isotope stratigraphy of river- and lake-ice archives winter hydroclimatic conditions, and can potentially be used to identify changing water sources or to provide important insights into ice formation processes and growth rates. However, accurate interpretations rely on known isotopic fractionation during ice growth. A one-dimensional diffusion model of...
Transient stress-coupling between the 1992 Landers and 1999 Hector Mine, California, earthquakes
Timothy Masterlark, H.F. Wang
2002, Bulletin of the Seismological Society of America (92) 1470-1486
A three-dimensional finite-element model (FEM) of the Mojave block region in southern California is constructed to investigate transient stress-coupling between the 1992 Landers and 1999 Hector Mine earthquakes. The FEM simulates a poroelastic upper-crust layer coupled to a viscoelastic lower-crust layer, which is decoupled from the upper mantle. FEM predictions...
Dynamic interpretation of slug tests in highly permeable aquifers
Brian R. Zurbuchen, Vitaly A. Zlotnik, James J. Butler Jr.
2002, Water Resources Research (38) 7-1-7-18
Considerable progress has been made in developing a theoretical framework for modeling slug test responses in formations with high hydraulic conductivity K. However, several questions of practical significance remain unresolved. Given the rapid and often oscillatory nature of test responses, the traditional hydrostatic relationship between the water level and the transducer‐measured...
Status and trends in atmospheric deposition and emissions near Atlanta, Georgia, 1986-99
N.E. Peters, T.P. Meyers, Brent T. Aulenbach
2002, Atmospheric Environment (36) 1577-1588
Wet and dry atmospheric deposition were investigated from weekly data, 1986-99 (1986-97 for dry deposition) at the Panola Mountain Research Watershed (PMRW), a forested research site 25 km, southeast of Atlanta, Georgia. Furthermore, the wet deposition was compared to that at three adjacent National Atmospheric Deposition Program's National Trends Network...
Stress triggering of the 1999 Hector Mine earthquake by transient deformation following the 1992 Landers earthquake
F. F. Pollitz, I. S. Sacks
2002, Bulletin of the Seismological Society of America (92) 1487-1496
The M 7.3 June 28, 1992 Landers and M 7.1 October 16, 1999 Hector Mine earthquakes, California, both right lateral strike-slip events on NNW-trending subvertical faults, occurred in close proximity in space and time in a region where recurrence times for surface-rupturing earthquakes are thousands of years. This suggests a...
Simulation of broadband ground motion including nonlinear soil effects for a magnitude 6.5 earthquake on the Seattle fault, Seattle, Washington
S. Hartzell, A. Leeds, A. Frankel, R. A. Williams, J. Odum, W. Stephenson, W. Silva
2002, Bulletin of the Seismological Society of America (92) 831-853
The Seattle fault poses a significant seismic hazard to the city of Seattle, Washington. A hybrid, low-frequency, high-frequency method is used to calculate broadband (0-20 Hz) ground-motion time histories for a M 6.5 earthquake on the Seattle fault. Low frequencies (1 Hz) are calculated by a stochastic method that uses...
The hydrothermolysis of the picrate anion: Kinetics and mechanism
D.S. Ross, I. Jayaweera
2002, Thermochimica Acta (384) 155-162
The hydrothermolysis of the picrate anion in aqueous solution has been studied at 260-325??C in liquid water. At starting pH values above 12, the disappearance of picrate begins immediately and is first order in OH-. At lower pH, there is an induction period preceding the disappearance, and over the pH...
Relationship of the 1999 Hector Mine and 1992 Landers fault ruptures to offsets on neogene faults and distribution of late Cenozoic basins in the eastern California shear zone
R.C. Jachens, V.E. Langenheim, J. C. Matti
2002, Bulletin of the Seismological Society of America (92) 1592-1605
This report examines the Hector Mine and Landers earthquakes in the broader context of faults and fault-related basins of the eastern California shear zone (ECSZ). We compile new estimates of total strike-slip offset (horizontal separation) at nearly 30 fault sites based on offset magnetic anomaly pairs. We also present a...
Identification of lithofacies using Kohonen self-organizing maps
H.-C. Chang, D. C. Kopaska-Merkel, H.-C. Chen
2002, Computers & Geosciences (28) 223-229
Lithofacies identification is a primary task in reservoir characterization. Traditional techniques of lithofacies identification from core data are costly, and it is difficult to extrapolate to non-cored wells. We present a low-cost automated technique using Kohonen self-organizing maps (SOMs) to identify systematically and objectively lithofacies from well log data. SOMs...
Historical and projected carbon balance of mature black spruce ecosystems across north america: The role of carbon-nitrogen interactions
Joy S. Clein, A. D. McGuire, X. Zhang, D. W. Kicklighter, J. M. Melillo, S.C. Wofsy, P.G. Jarvis, J.M. Massheder
2002, Conference Paper, Plant and Soil
The role of carbon (C) and nitrogen (N) interactions on sequestration of atmospheric CO2 in black spruce ecosystems across North America was evaluated with the Terrestrial Ecosystem Model (TEM) by applying parameterizations of the model in which C-N dynamics were either coupled or uncoupled. First, the performance of the parameterizations,...
