Population structure and the evolution of sexual size dimorphism and sex ratios in an insular population of Florida box turtles (Terrapene carolina bauri)
C.K. Dodd Jr.
1997, Canadian Journal of Zoology (75) 1495-1507
Hypotheses in the chelonian literature suggest that in species with sexual size dimorphism, the smaller sex will mature at a smaller size and a younger age than the larger sex, sex ratios should be biased in favor of the earlier maturing sex, and deviations from a 1:1 sex ratio result...
Nowcast model for hazardous material spill prevention and response, San Francisco Bay, California
Ralph T. Cheng, Wayne L. Wilmot, Jerry A. Galt
1997, Conference Paper, Oceans Conference Record (IEEE)
The National Oceanic and Atmospheric Administration (NOAA) installed the Physical Oceanographic Real-time System (PORTS) in San Francisco Bay, California, to provide real-time observations of tides, tidal currents, and meteorological conditions to, among other purposes, guide hazardous material spill prevention and response. Integrated with nowcast modeling techniques and dissemination of real-time...
Thermal regime of the San Andreas fault near Parkfield, California
J.H. Sass, C.F. Williams, A.H. Lachenbruch, S.P. Galanis Jr., F.V. Grubb
1997, Journal of Geophysical Research B: Solid Earth (102) 27575-27585
Knowledge of the temperature variation with depth near the San Andreas fault is vital to understanding the physical processes that occur within the fault zone during earthquakes and creep events. Parkfield is near the southern end of the Coast Ranges segment of the San Andreas fault. This segment has higher...
Regional landslide-hazard evaluation using landslide slopes, Western Wasatch County, Utah
M.D. Hylland, Mark Lowe
1997, Environmental & Engineering Geoscience (3) 31-43
Landsliding has historically been one of the most damaging geologic hazards in western Wasatch County, Utah. Accordingly, we mapped and analyzed landslides (slumps and debris slides) in the area to provide an empirical basis for regional landslide-hazard evaluation. The 336 landslides in the...
Estimating the diminution of shear-wave amplitude with distance: Application to the Los Angeles, California, urban area
S. C. Harmsen
1997, Bulletin of the Seismological Society of America (87) 888-903
The rate of decay with distance of shear-wave amplitude, computed from 20-sec S-wave spectra, is determined from TERRAscope records of small earthquakes in the greater Los Angeles area. Piecewise log-linear interpolation functions and traditional diminution functions are used to fit spectral decay to a...
A reconnaissance study of oxygen, hydrogen and strontium isotopes in geochemically diverse lakes, Western Nebraska, USA
D.C. Gosselin, P.E. Nabelek, Z. E. Peterman, S. Sibray
1997, Journal of Paleolimnology (17) 51-65
Reconnaissance ??18O,, ??D, and ??87Sr data for fifteen lakes in the Western Lakes Region of the Sand Hills of Nebraska indicate dynamic hydrologic systems. The rather narrow range of ??87Sr from lake water (1.1 to 2.1) and groundwater (0.9 to 1.7) indicates that the groundwater is generally unradiogenic. Groundwater residence...
The 1995 revision of the joint US/UK geomagnetic field models - I. Secular variation
S. Macmillan, D.R. Barraclough, J.M. Quinn, R.J. Coleman
1997, Earth, Planets and Space (49) 229-243
We present the methods used to derive mathematical models of global secular variation of the main geomagnetic field for the period 1985 to 2000. These secular-variation models are used in the construction of the candidate US/UK models for the Definitive Geomagnetic Reference Field at 1990, the International Geomagnetic Reference Field...
Hydrological and chemical estimates of the water balance of a closed-basin lake in north central Minnesota
James W. LaBaugh, Thomas C. Winter, Donald O. Rosenberry, Paul F. Schuster, Michael M. Reddy, George R. Aiken
1997, Water Resources Research (33) 2799-2812
Chemical mass balances for sodium, magnesium, chloride, dissolved organic carbon, and oxygen 18 were used to estimate groundwater seepage to and from Williams Lake, Minnesota, over a 15-month period, from April 1991 through June 1992. Groundwater seepage to the lake and seepage from the lake to groundwater were determined independently...
Late Mesozoic and Cenozoic thermotectonic evolution of the central Brooks Range and adjacent North Slope foreland basin, Alaska: Including fission track results from the Trans-Alaska Crustal Transect (TACT)
P. B. O’Sullivan, J.M. Murphy, A.E. Blythe
1997, Journal of Geophysical Research B: Solid Earth (102) 20821-20845
Apatite fission track data are used to evaluate the thermal and tectonic history of the central Brooks Range and the North Slope foreland basin in northern Alaska along the northern leg of the Trans-Alaska Crustal Transect (TACT). Fission track analyses of the detrital apatite grains in most sedimentary units resolve...
Normalizing rainfall/debris-flow thresholds along the U.S. Pacific coast for long-term variations in precipitation climate
Raymond C. Wilson
1997, Conference Paper, International Conference on Debris-Flow Hazards Mitigation: Mechanics, Prediction, and Assessment, Proceedings
Broad-scale variations in long-term precipitation climate may influence rainfall/debris-flow threshold values along the U.S. Pacific coast, where both the mean annual precipitation (MAP) and the number of rainfall days (#RDs) are controlled by topography, distance from the coastline, and geographic latitude. Previous authors have proposed that rainfall thresholds are directly...
Evaluation of field and laboratory research on scour at bridge piers in the United States
David S. Mueller, J. Sterling Jones
1997, Conference Paper, Proceedings, Congress of the International Association of Hydraulic Research, IAHR
The Federal Highway Administration sponsored a laboratory research at Colorado State University and field data collection with the US Geological Survey, to evaluate the effects of bed material on the depth of scour. Correction factors are compared to include the effect of bed material in the HEC-18 equation. The HEC-18...
Viscoelastic coupling model of the San Andreas fault along the Big Bend, southern California
J.C. Savage, M. Lisowski
1997, Journal of Geophysical Research B: Solid Earth (103) 7281-7292
The big bend segment of the San Andreas fault is the 300-km-long segment in southern California that strikes about N65°W, roughly 25° counterclockwise from the local tangent to the small circle about the Pacific-North America pole of rotation. The broad distribution of deformation of trilateration networks along this segment implies...
Crustal deformation in southern California using SAR interferometry
G. Peltzer, P. Rosen, F. Rogez, K. Hudnut
1997, European Space Agency, (Special Publication) ESA SP 545-548
By combining pairs of ERS-1/2 SAR images of Southern California spanning long time intervals (1-4 years), we were able to measure the rate of slow deformation processes along faults activated during the Landers 1992 earthquake. Interferograms revealed several centimeters of post-seismic rebound in step-overs of the 1992 break, with a...
Petrography and geochemistry of selected lignite beds in the Gibbons Creek mine (Manning Formation, Jackson Group, Paleocene) of east-central Texas
Peter D. Warwick, Sharon S. Crowley, Leslie F. Ruppert, James Pontolillo
1997, International Journal of Coal Geology (34) 307-326
This study examined the petrographic and geochemical characteristics of two lignite beds (3500 and 4500 beds, Manning Formation, Jackson Group, Eocene) that are mined at the Gibbons Creek mine in east-central Texas. The purpose of the study was to identify the relations among sample ash yield, coal petrography, and trace-element...
Effect of flagellates on free-living bacterial abundance in an organically contaminated aquifer
N.E. Kinner, R.W. Harvey, M. Kazmierkiewicz-Tabaka
1997, FEMS Microbiology Reviews (20) 249-259
Little is known about the role of protists in the saturated subsurface. Porous media microcosms containing bacteria and protists, were used to determine whether flagellates from an organically contaminated aquifer could substantively affect the number of free- living bacteria (FLB). When flagellates were present, the 3-40% maximum breakthrough of fluorescent...
Spring prey use by double-crested cormorants on the Penobscot River, Maine, USA
B.F. Blackwell, W.B. Krohn, N.R. Dube, A.J. Godin
1997, Waterbirds (20) 77-86
We analyzed 2 sets of data for Double-crested Cormorant (Phalacrocorax auritus) stomach contents (including esophageal contents) that were collected from April through June of 1986-1988 (N = 580) and 1992-1993 (N = 200) on the Penobscot River, Maine. Our objectives were to examine temporal and spatial variation in the spring...
Application of two direct runoff prediction methods in Puerto Rico
N. Sepulveda
1997, Journal of Hydrologic Engineering (2) 10-17
Two methods for predicting direct runoff from rainfall data were applied to several basins and the resulting hydrographs compared to measured values. The first method uses a geomorphology-based unit hydrograph to predict direct runoff through its convolution with the excess rainfall hyetograph. The second method shows how the resulting hydraulic...
Evaluation of unconfined-aquifer parameters from pumping test data by nonlinear least squares
M. Heidari, A. Moench
1997, Journal of Hydrology (192) 300-313
Nonlinear least squares (NLS) with automatic differentiation was used to estimate aquifer parameters from drawdown data obtained from published pumping tests conducted in homogeneous, water-table aquifers. The method is based on a technique that seeks to minimize the squares of residuals between observed and calculated drawdown subject to bounds that...
A new approach for analyzing bird densities from variable circular-plot counts
S.G. Fancy
1997, Pacific Science (51) 107-114
An approach for calculating bird densities from variable circular-plot counts is described. The approach differs from previous methods in that data from several surveys are pooled and detection distances are adjusted as if all distances were recorded by a single observer under a given set of field conditions. Adjustments for...
Benthic boundary layer processes in the Lower Florida Keys
D. L. Lavoie, M. D. Richardson, C. Holmes
1997, Geo-Marine Letters (17) 232-236
This special issue of Geo-Marine Letters, "Benthic Boundary Layer Processes in the Lower Florida Keys," includes 12 papers that present preliminary results from the Key West Campaign. The Dry Tortugas and Marquesas Keys test sites were selected by a group of 115 scientists and technicians to study benthic boundary layer...
Multiphase flow modeling of a crude-oil spill site with a bimodal permeability distribution
Leslie A. Dillard, Hedeff I. Essaid, William N. Herkelrath
1997, Water Resources Research (33) 1617-1632
Fluid saturation, particle-size distribution, and porosity measurements were obtained from 269 core samples collected from six boreholes along a 90-m transect at a subregion of a crude-oil spill site, the north pool, near Bemidji, Minnesota. The oil saturation data, collected 11 years after the spill, showed an irregularly shaped oil...
Harmonic Analysis of Sedimentary Cyclic Sequences in Kansas, Midcontinent, USA
D. F. Merriam, J.E. Robinson
1997, Mathematical Geology (29) 953-962
Several stratigraphic sequences in the Upper Carboniferous (Pennsylvanian) in Kansas (Midcontinent, USA) were analyzed quantitatively for periodic repetitions. The sequences were coded by lithologic type into strings of datasets. The strings then were analyzed by an adaptation of a one-dimensional Fourier transform analysis and examined for evidence of periodicity. The...
Estimation of αL, velocity, Kd and confidence limits from tracer injection test data
James Broermann, R.L. Bassett, Edwin P. Weeks, Mark Borgstrom
1997, Groundwater (35) 1066-1076
Bromide and boron were used as tracers during an injection experiment conducted at an artificial recharge facility near Stanton, Texas. The Ogallala aquifer at the Stanton site represents a heterogeneous alluvial environment and provides the opportunity to report scale dependent dispersivities at observation distances of 2 to 15 m in...
Efficacy of a vacuum benthos sampler for collecting demersal fish eggs from gravel substratum
Carl R. Ruetz III, Cecil A. Jennings
1997, Ecology of Freshwater Fish (6) 241-244
We used two densities of eggs (low=900 eggs/m2; high=5100 eggs/m2) in laboratory experiments to estimate the recovery efficiency of the Brown benthos sampler for collecting fish eggs from gravel substrate and to determine if differences (e. g., 5-fold) in egg density in the substratum could be detected with the sampler....
Carbon isotopes in biological carbonates: Respiration and photosynthesis
T.A. McConnaughey, J. Burdett, J. F. Whelan, C. K. Paull
1997, Geochimica et Cosmochimica Acta (61) 611-622
Respired carbon dioxide is an important constituent in the carbonates of most air breathing animals but is much less important in the carbonates of most aquatic animals. This difference is illustrated using carbon isotope data from freshwater and terrestrial snails, ahermatypic corals,...
