Migration of dispersive GPR data
M.H. Powers, C.P. Oden
Slob E.Yarovoy A.Rhebergen J.B., editor(s)
2004, Conference Paper, Proceedings of the Tenth International Conference Ground Penetrating Radar, GPR 2004
Electrical conductivity and dielectric and magnetic relaxation phenomena cause electromagnetic propagation to be dispersive in earth materials. Both velocity and attenuation may vary with frequency, depending on the frequency content of the propagating energy and the nature of the relaxation phenomena. A minor amount of velocity dispersion is associated with...
Log Pearson type 3 quantile estimators with regional skew information and low outlier adjustments
V.W. Griffis, Jery R. Stedinger, T.A. Cohn
2004, Water Resources Research (40)
The recently developed expected moments algorithm (EMA) [Cohn et al., 1997] does as well as maximum likelihood estimations at estimating log‐Pearson type 3 (LP3) flood quantiles using systematic and historical flood information. Needed extensions include use of a regional skewness estimator and its precision to be consistent with Bulletin 17B. Another...
Decadal-scale climate drivers for glacial dynamics in Glacier National Park, Montana, USA
G.T. Pederson, D.B. Fagre, S.T. Gray, L.J. Graumlich
2004, Geophysical Research Letters (31)
Little Ice Age (14th-19th centuries A.D.) glacial maxima and 20th century retreat have been well documented in Glacier National Park, Montana, USA. However, the influence of regional and Pacific Basin driven climate variability on these events is poorly understood. We use tree-ring reconstructions of North Pacific surface temperature anomalies and...
Joint inversion of gravity and arrival time data from Parkfield: New constraints on structure and hypocenter locations near the SAFOD drill site
S. Roecker, C. Thurber, D. McPhee
2004, Geophysical Research Letters (31)
Taking advantage of large datasets of both gravity and elastic wave arrival time observations available for the Parkfield, California region, we generated an image consistent with both types of data. Among a variety of strategies, the best result was obtained from a simultaneous inversion with a stability requirement that encouraged...
Rupture models with dynamically determined breakdown displacement
D.J. Andrews
2004, Bulletin of the Seismological Society of America (94) 769-775
The critical breakdown displacement, Dc, in which friction drops to its sliding value, can be made dependent on event size by specifying friction to be a function of variables other than slip. Two such friction laws are examined here. The first is designed to achieve accuracy and smoothness in discrete...
Application of chemical coagulation aids for the removal of suspended solids (TSS) and phosphorus from the microscreen effluent discharge of an intensive recirculating aquaculture system
J.M. Ebeling, S.R. Ogden, P.L. Sibrell, K.L. Rishel
2004, North American Journal of Aquaculture (66) 198-207
An evaluation of two commonly used coagulation-flocculation aids (alum and ferric chloride) was conducted to determine optimum conditions for treating the backwash effluent from microscreen filters in an intensive recirculating aquaculture system. Tests were carried out to evaluate the dosages and conditions (mixing and flocculation stirring speeds, durations, and settling...
Mechanisms of electron acceptor utilization: Implications for simulating anaerobic biodegradation
M.E. Schreiber, G.R. Carey, D. T. Feinstein, J.M. Bahr
2004, Journal of Contaminant Hydrology (73) 99-127
Simulation of biodegradation reactions within a reactive transport framework requires information on mechanisms of terminal electron acceptor processes (TEAPs). In initial modeling efforts, TEAPs were approximated as occurring sequentially, with the highest energy-yielding electron acceptors (e.g. oxygen) consumed before those that yield less energy (e.g., sulfate). Within this framework in...
Assessing denitrification in groundwater using natural gradient tracer tests with 15N: In situ measurement of a sequential multistep reaction
Richard L. Smith, J.K. Bohlke, Stephen P. Garabedian, Kinga M. Revesz, Tadashi Yoshinari
2004, Water Resources Research (40) 1-17
Denitrification was measured within a nitrate‐contaminated aquifer on Cape Cod, Massachusetts, using natural gradient tracer tests with 15N nitrate. The aquifer contained zones of relatively high concentrations of nitrite (up to 77 μM) and nitrous oxide (up to 143 μM) and has been the site of previous studies examining ground water...
A modern vs. Permian black shale - the hydrography, primary productivity, and water-column chemistry of deposition
D.Z. Piper, R.B. Perkins
2004, Chemical Geology (206) 177-197
The sediment currently accumulating in the Cariaco Basin, on the continental shelf of Venezuela, has an elevated organic-carbon content of approximately 5%; is accumulating under O2-depleted bottom-water conditions (SO42- reduction); is composed dominantly of foraminiferal calcite, diatomaceous silica, clay, and silt; and is dark greenish gray in color. Upon lithification,...
CORRELATOR 5.2 - A program for interactive lithostratigraphic correlation of wireline logs
Ricardo A. Olea
2004, Computers & Geosciences (30) 561-567
The limited radius of investigation of petrophysical measurements made in boreholes and the relatively large distances between wells result in an incomplete sensing of the subsurface through well logging. CORRELATOR is a program for estimating geological properties between logged boreholes. An initial and fundamental step is the lithostratigraphic correlation of...
Earthquake source parameters determined by the SAFOD Pilot Hole seismic array
K. Imanishi, W.L. Ellsworth, S. G. Prejean
2004, Geophysical Research Letters (31)
We estimate the source parameters of #3 microearthquakes by jointly analyzing seismograms recorded by the 32-level, 3-component seismic array installed in the SAFOD Pilot Hole. We applied an inversion procedure to estimate spectral parameters for the omega-square model (spectral level and corner frequency) and Q to displacement amplitude spectra. Because...
Comparison of genetic diversity in the recently founded Connecticut River Atlantic salmon population to that of its primary donor stock, Maine's Penobscot River
A.P. Spidle, T.L. King, B. H. Letcher
2004, Aquaculture (236) 253-265
Anadromous Atlantic salmon returning to the Connecticut River (CR) from 1996 to 1999 were assayed for variability at nine microsatellite DNA loci. Heterozygosity and allele frequencies were compared to the anadromous Atlantic salmon returning to Maine's Penobscot River from 1998 to 2000. The Penobscot River was the primary source of...
Effects of radiotransmitters on the reproductive performance of Cassin's auklets
Joshua T. Ackerman, Josh Adams, John Y. Takekawa, Harry R. Carter, Darrell L. Whitworth, Scott H. Newman, Richard T. Golightly, Dennis L. Orthmeyer
2004, Wildlife Society Bulletin (32) 1229-1241
We examined whether radiotransmitters adversely affected the reproductive performance of Cassin's auklets (Ptychoramphus aleuticus) breeding on the California Channel Islands during 1999-2001. We attached external radiotransmitters to 1 partner in 108 Cassin's auklet pairs after nest initiation and used 131 unmarked, but handled, pairs as controls. Compared to alpha chicks...
Plant functional traits in relation to fire in crown-fire ecosystems
Juli G. Pausas, Ross A. Bradstock, David A. Keith, Jon E. Keeley
2004, Ecology (85) 1085-1100
Disturbance is a dominant factor in many ecosystems, and the disturbance regime is likely to change over the next decades in response to land-use changes and global warming. We assume that predictions of vegetation dynamics can be made on the basis of a set of life-history traits that characterize the...
Some statistical relationships between stream sediment and soil geochemistry in northwestern Wisconsin - can stream sediment compositions be used to predict compositions of soils in glaciated terranes?
W.F. Cannon, L. G. Woodruff, S. Pimley
2004, Journal of Geochemical Exploration (81) 29-46
Mean stream sediment chemical compositions from northwestern Wisconsin in the north central United States, based on more than 800 samples, differ significantly from mean A-horizon and C-horizon soil compositions, based on about 380 samples of each horizon. Differences by a factor greater than 1.5 exist for some elements (Ca, Mn,...
At-sea activity and diving behavior of a radio-tagged Marbled Murrelet in central California
Laird A. Henkel, Esther E. Burkett, John Y. Takekawa
2004, Waterbirds (27) 9-12
Radio-telemetry was used to continuously monitor the at-sea activity of an adult Marbled Murrelet (Brachyramphus marmoratus) nesting in Santa Cruz County, California. From 05.39 h on 28 May 1997, to 05.14 h on 29 May 1997, the murrelet was followed by tracking teams at Año Nuevo Bay. Between 05.44 h...
Land-level changes from a late Holocene earthquake in the northern Puget lowland, Washington
H.M. Kelsey, B. Sherrod, S. Y. Johnson, S. V. Dadisman
2004, Geology (32) 469-472
An earthquake, probably generated on the southern Whidbey Island fault zone, caused 1-2 m of ground-surface uplift on central Whidbey Island ???2800-3200 yr ago. The cause of the uplift is a fold that grew coseismically above a blind fault that was the earthquake source. Both the fault and the fold...
Neoproterozoic A-type granitoids of the central and southern Appalachians: Intraplate magmatism associated with episodic rifting of the Rodinian supercontinent
R.P. Tollo, J. N. Aleinikoff, M. J. Bartholomew, D.W. Rankin
2004, Precambrian Research (128) 3-38
Emplacement of compositionally distinctive granitic plutons accompanied two pulses (765-680 and 620-550Ma) of crustal extension that affected the Rodinian craton at the present location of the central Appalachians during the Neoproterozoic. The dominantly metaluminous plutons display mineralogical and geochemical characteristics of A-type granites including high FeO t/MgO ratios, high abundances...
Use of digital multispectral videography to assess seagrass distribution in San Quintin Bay, Baja California, Mexico
David H. Ward, T. Lee Tibbitts, Alexandra Morton, Eduardo Carrera-Gonzalez, R. Kempka
2004, Ciencias Marinas (30) 47-60
Apparent threats to the spatial distribution of seagrass in San Quintín Bay prompted us to make a detailed assessment of habitats in the bay. Six coastal habitats and three seagrass subclasses were delineated using airborne digital multispectral videography (DMSV). Eelgrass, Zostera marina, was the predominant seagrass and covered 40% (1949...
Testing a basic assumption of shrubland fire management: h=How important is fuel age?
Max A. Moritz, Jon E. Keeley, Edward A. Johnson, Andrew A. Schaffner
2004, Frontiers in Ecology and the Environment (2) 67-72
This year's catastrophic wildfires in southern California highlight the need for effective planning and management for fire-prone landscapes. Fire frequency analysis of several hundred wildfires over a broad expanse of California shrublands reveals that there is generally not, as is commonly assumed, a strong relationship between fuel age and fire...
Effects of wave shape on sheet flow sediment transport
T.-J. Hsu, D.M. Hanes
2004, Journal of Geophysical Research C: Oceans (109)
A two-phase model is implemented to study the effects of wave shape on the transport of coarse-grained sediment in the sheet flow regime. The model is based on balance equations for the average mass, momentum, and fluctuation energy for both the fluid and sediment phases. Model simulations indicate that the...
Short-wavelength infrared (1.3-2.6 μm) observations of the nucleus of Comet 19P/Borrelly
Laurence A. Soderblom, D.T. Britt, R. H. Brown, B. J. Buratti, Randolph L. Kirk, T.C. Owen, R.V. Yelle
2004, Icarus (167) 100-112
During the last two minutes before closest approach of Deep Space 1 to Comet 19P/Borrelly, a long exposure was made with the short-wavelength infrared (SWIR) imaging spectrometer. The observation yielded 46 spectra covering 1.3–2.6 μm; the footprint of each spectrum was ∼160 m × width of the nucleus. Borrelly's highly variegated and...
Elevational dependence of projected hydrologic changes in the San Francisco Estuary and watershed
N. Knowles, D.R. Cayan
2004, Climatic Change (62) 319-336
California's primary hydrologic system, the San Francisco Estuary and its upstream watershed, is vulnerable to the regional hydrologic consequences of projected global climate change. Previous work has shown that a projected warming would result in a reduction of snowpack storage leading to higher winter and lower spring-summer streamflows and...
Saltcedar (Tamarix ramosissima) invasion alters organic matter dynamics in a desert stream
T.A. Kennedy, S.E. Hobbie
2004, Freshwater Biology (49) 65-76
1. We investigated the impacts of saltcedar invasion on organic matter dynamics in a spring-fed stream (Jackrabbit Spring) in the Mojave Desert of southern Nevada, U.S.A., by experimentally manipulating saltcedar abundance. 2. Saltcedar heavily shaded Jackrabbit Spring and shifted the dominant organic matter inputs from autochthonous production that was available...
Complete genome sequence of Fer-de-Lance Virus reveals a novel gene in reptilian Paramyxoviruses
Gael Kurath, W.N. Batts, W. Ahne, J. R. Winton
2004, Journal of Virology (78) 2045-2056
The complete RNA genome sequence of the archetype reptilian paramyxovirus, Fer-de-Lance virus (FDLV), has been determined. The genome is 15,378 nucleotides in length and consists of seven nonoverlapping genes in the order 3??? N-U-P-M-F-HN-L 5???, coding for the nucleocapsid, unknown, phospho-, matrix, fusion, hemagglutinin-neuraminidase, and large polymerase proteins, respectively. The...
