Variations in creep rate along the Hayward Fault, California, interpreted as changes in depth of creep
R.W. Simpson, J. J. Lienkaemper, J.S. Galehouse
2001, Geophysical Research Letters (28) 2269-2272
Variations ill surface creep rate along the Hayward fault are modeled as changes in locking depth using 3D boundary elements. Model creep is driven by screw dislocations at 12 km depth under the Hayward and other regional faults. Inferred depth to locking varies along strike from 4-12 km. (12 km...
Trends in long-period seismicity related to magmatic fluid compositions
M.M. Morrissey, B. A. Chouet
2001, Journal of Volcanology and Geothermal Research (108) 265-281
Sound speeds and densities are calculated for three different types of fluids: gas-gas mixture; ash-gas mixture; and bubbly liquid. These fluid properties are used to calculate the impedance contrast (Z) and crack stiffness (C) in the fluid-driven crack model (Chouet: J. Geophys. Res., 91 (1986) 13,967; 101 (1988) 4375; A...
Evaluation of flash-flood discharge forecasts in complex terrain using precipitation
D. Yates, T.T. Warner, E.A. Brandes, G.H. Leavesley, Jielun Sun, C.K. Mueller
2001, Journal of Hydrologic Engineering (6) 265-274
Operational prediction of flash floods produced by thunderstorm (convective) precipitation in mountainous areas requires accurate estimates or predictions of the precipitation distribution in space and time. The details of the spatial distribution are especially critical in complex terrain because the watersheds are generally small in size, and small position errors...
Nitrogen input to the Gulf of Mexico
D. A. Goolsby, W.A. Battaglin, Brent T. Aulenbach, R. P. Hooper
2001, Conference Paper
Historical streamflow and concentration data were used in regression models to estimate the annual flux of nitrogen (N) to the Gulf of Mexico and to determine where the nitrogen originates within the Mississippi Basin. Results show that for 1980-1996 the mean annual total N flux to the Gulf of Mexico...
Delineating a recharge area for a spring using numerical modeling, Monte Carlo techniques, and geochemical investigation
R. J. Hunt, J. J. Steuer, M.T.C. Mansor, T.D. Bullen
2001, Ground Water (39) 702-712
Recharge areas of spring systems can be hard to identify, but they can be critically important for protection of a spring resource. A recharge area for a spring complex in southern Wisconsin was delineated using a variety of complementary techniques. A telescopic mesh refinement (TMR) model was constructed from an...
Climate regimes and water temperature changes in the Columbia River: bioenergetic implications for predators of juvenile salmon
J.H. Petersen, J.F. Kitchell
2001, Canadian Journal of Fisheries and Aquatic Sciences (58) 1831-1841
We examined how climatic regime shifts may have affected predation rates on juvenile Pacific salmonids (Oncorhynchus spp.) by northern squawfish (Ptychocheilus oregonensis, also called northern pikeminnow), smallmouth bass (Micropterus dolomieu), and walleye (Stizostedion vitreum) in the Columbia River. During 1933-1996, oceanic, coastal, and freshwater indices of climate were highly correlated,...
The effect of depuration on transmission of Aeromonas salmonicida between the freshwater bivalve Amblema plicata Arctic char
C. E. Starliper
2001, Journal of Aquatic Animal Health (13) 56-62
A model system was used to study bacterial fish pathogen transmission between the freshwater bivalve Amblema plicata and two strains (Nauyuk and Labrador) of Arctic char Salvelinus alpinus. Aeromonas salmonicida, the cause of fish furunculosis, was readily transmitted from Arctic char to A. plicata and vice versa via simple cohabitation. Clinical furunculosis was artificially established...
Mercury contamination and growth rate two piscivore populations
C.P. Stafford, T.A. Haines
2001, Environmental Toxicology and Chemistry (20) 2099-2101
We found no relationship between fish growth rate and mercury concentration in a lake trout population and conditional support for an inverse relationship in a smallmouth bass population. A bioenergetics model indicated that mercury concentration was more responsive to dietary mercury intake than to growth rate. When biodilution is evident,...
Association of amphibians with attenuation of ultraviolet-b radiation in montane ponds
M. J. Adams, Daniel E. Schindler, R. Bruce Bury
2001, Oecologia (128) 519-525
Ambient ultraviolet-b (UV-B) radiation (280–320 nm) has increased at north-temperate latitudes in the last two decades. UV-B can be detrimental to amphibians, and amphibians have shown declines in some areas during this same period. We documented the distribution of amphibians and salmonids in 42 remote, subalpine and alpine ponds in Olympic...
Remnant colloform pyrite at the haile gold deposit, South Carolina: A textural key to genesis
N. Foley, R. A. Ayuso, R.R. Seal II
2001, Economic Geology (96) 891-902
Auriferous iron sulfide-bearing deposits of the Carolina slate belt have distinctive mineralogical and textural features-traits that provide a basis to construct models of ore deposition. Our identification of paragenetically early types of pyrite, especially remnant colloform, crustiform, and layered growth textures of pyrite containing electrum and pyrrhotite, establishes unequivocally that...
Seismic tomography shows that upwelling beneath Iceland is confined to the upper mantle
G.R. Foulger, M.J. Pritchard, B.R. Julian, J.R. Evans, R. M. Allen, G. Nolet, W. J. Morgan, B. H. Bergsson, P. Erlendsson, S. Jakobsdottir, S. Ragnarsson, R. Stefansson, K. Vogfjord
2001, Geophysical Journal International (146) 504-530
We report the results of the highest-resolution teleseismic tomography study yet performed of the upper mantle beneath Iceland. The experiment used data gathered by the Iceland Hotspot Project, which operated a 35-station network of continuously recording, digital, broad-band seismometers over all of Iceland 1996-1998. The structure of the upper mantle...
Rehabilitation of gypsum-mined lands in the Indian desert
K.D. Sharma, S. Kumar, L. P. Gough
2001, Arid Soil Research and Rehabilitation (15) 61-76
The economic importance of mining in the Indian Desert is second only to agriculture. Land disturbed by mining, however, has only recently been the focus of rehabilitation efforts. This research assesses the success of rehabilitation plans used to revegetate gypsum mine spoils within the environmental constraints of the north-west Indian...
Effects of dissolved carbon dioxide on the physiology and behavior of fish artificial streams
R. M. Ross, W. F. Krise, Lori A. Redell, R. M. Bennett
2001, Environmental Toxicology (16) 84-95
A new technology for treating waters contaminated with acid mine drainage involves the dissolution of limestone particles using carbon dioxide at pressures above ambient. Because of the fish health risks associated with episodes of high carbon dioxide levels in treated waters, we subjected three species of fish, brook trout (Salvelinus...
River flow mass exponents with fractal channel networks and rainfall
B.M. Troutman, T.M. Over
2001, Advances in Water Resources (24) 967-989
An important problem in hydrologic science is understanding how river flow is influenced by rainfall properties and drainage basin characteristics. In this paper we consider one approach, the use of mass exponents, in examining the relation of river flow to rainfall and the channel network, which provides the primary conduit...
Statistical self-similarity of width function maxima with implications to floods
S.A. Veitzer, V.K. Gupta
2001, Advances in Water Resources (24) 955-965
Recently a new theory of random self-similar river networks, called the RSN model, was introduced to explain empirical observations regarding the scaling properties of distributions of various topologic and geometric variables in natural basins. The RSN model predicts that such variables exhibit statistical simple scaling, when indexed by Horton-Strahler order....
1r2dinv: A finite-difference model for inverse analysis of two dimensional linear or radial groundwater flow
Geoffrey C. Bohling, J.J. Butler Jr.
2001, Computers & Geosciences (27) 1147-1156
We have developed a program for inverse analysis of two-dimensional linear or radial groundwater flow problems. The program, 1r2dinv, uses standard finite difference techniques to solve the groundwater flow equation for a horizontal or vertical plane with heterogeneous properties. In radial mode, the program simulates flow to a well in...
Formation and failure of volcanic debris dams in the Chakachatna River valley associated with eruptions of the Spurr volcanic complex, Alaska
C. F. Waythomas
2001, Geomorphology (39) 111-129
The formation of lahars and a debris avalanche during Holocene eruptions of the Spurr volcanic complex in south-central Alaska have led to the development of volcanic debris dams in the Chakachatna River valley. Debris dams composed of lahar and debris-avalanche deposits formed at least five times in the last 8000-10,000...
Geology, coal quality, and resources of the Antaramut-Kurtan-Dzoragukh coal field, north-central Armenia
B.S. Pierce, A. Martirosyan, G. Malkhasian, S. Harutunian, G. Harutunian
2001, International Journal of Coal Geology (45) 267-279
The Antaramut-Kurta-Dzoragukh (AKD) coal deposit is a previously unrecognized coal field in north-central Armenia. Coal has been known to exist in the general vicinity since the turn of the century, but coal was thought to be restricted to a small (1 km2) area only near the village of Antaramut. However,...
Determination of element affinities by density fractionation of bulk coal samples
X. Querol, Z. Klika, Z. Weiss, R. B. Finkelman, A. Alastuey, R. Juan, A. Lopez-Soler, F. Plana, A. Kolker, S.R.N. Chenery
2001, Fuel (80) 83-96
A review has been made of the various methods of determining major and trace element affinities for different phases, both mineral and organic in coals, citing their various strengths and weaknesses. These include mathematical deconvolution of chemical analyses, direct microanalysis, sequential extraction procedures and density fractionation. A new methodology combining...
Modeling Klamath River system operations for quantity and quality
Sharon G. Campbell, R. Blair Hanna, Marshall Flug, John F. Scott
2001, Journal of Water Resources Planning and Management (127) 284-294
Alternative water management scenarios for a portion of the mainstem Klamath River from Keno, Oregon, to Seiad Valley, California, were evaluated using computer models of water quantity (MODSIM) and quality (HEC-5Q). These models were used to explore the potential for changing system operations to improve summer/fall water quality conditions to...
Comparision between crustal density and velocity variations in Southern California
V.E. Langenheim, E. Hauksson
2001, Geophysical Research Letters (28) 3087-3090
We predict gravity from a three-dimensional Vp model of the upper crust and compare it to the observed isostatic residual gravity field. In general this comparison shows that the isostatic residual gravity field reflects the density variations in the upper to middle crust. Both data sets show similar density variations...
Susceptibility of the Siberian polecat to subcutaneous and oral Yersinia pestis exposure
K.T. Castle, D. Biggins, L.G. Carter, M. Chu, Kim Innes, J. Wimsatt
2001, Journal of Wildlife Diseases (37) 746-754
To determine if the Siberian polecat (Mustela eversmannii) represents a suitable model for the study of plague pathogenesis and prevention in the black-footed ferret (Mustela nigripes), polecats were exposed to 103, 107, or 1010 Yersinia pestis organisms by subcutaneous injection; an additional group was exposed to Y. pestis via ingestion of a plague-killed mouse....
Distribution of fine-scale mantle heterogeneity from observations of Pdiff coda
P.S. Earle, P.M. Shearer
2001, Bulletin of the Seismological Society of America (91) 1875-1881
We present stacked record sections of Global Seismic Network data that image the average amplitude and polarization of the high-frequency Pdiff coda and investigate their implications on the depth extent of fine-scale (~10 km) mantle heterogeneity. The extended 1-Hz coda lasts for at least 150 sec and is observed to...
Strontium isotopes reveal distant sources of architectural timber in Chaco Canyon, New Mexico
N.B. English, J.L. Betancourt, J.S. Dean, Jay Quade
2001, Proceedings of the National Academy of Sciences of the United States of America (98) 11891-11896
Between A.D. 900 and 1150, more than 200,000 conifer trees were used to build the prehistoric great houses of Chaco Canyon, New Mexico, in what is now a treeless landscape. More than one-fifth of these timbers were spruce (Picea) or fir (Abies) that were hand-carried from isolated mountaintops 75-100 km...
Singular spectrum analysis for time series with missing data
D. H. Schoellhamer
2001, Geophysical Research Letters (28) 3187-3190
Geophysical time series often contain missing data, which prevents analysis with many signal processing and multivariate tools. A modification of singular spectrum analysis for time series with missing data is developed and successfully tested with synthetic and actual incomplete time series of suspended-sediment concentration from San Francisco Bay. This method...
