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Page 4690, results 117226 - 117250

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Publication Extents

Not all publications have extents, not all extents are completely accurate
Ice gouge processes in the Alaskan Beaufort Sea
Douglas M. Rearic, Edward J. Ticken
1988, Technical Council on Cold Regions Engineering Monograph 85-107
A generalized picture of ice gouge characteristics from shallow inshore depths to the outer shelf at about 60 m of water is presented. Data from recent studies show that the size and quantity of gouging increases in an offshore direction to depths of about 45 m where this trend then...
Nitrogen cycling between sediment and the shallow-water column in the transition zone of the Potomac River and estuary. I. Nitrate and ammonium fluxes
N.S. Simon
1988, Estuarine, Coastal and Shelf Science (26) 483-497
A three-year study of seasonal variation in water-column and sediment nitrogen species was conducted in the transition zone of the Potomac River 35 m from the Virginia shore at a site with an average water-column depth of approximately 1 m over sandy sediment. A diffusion-controlled sampler was used to collect...
Migration of historical earthquakes in California
C.-Y. King, Z. Ma
1988, Pure and Applied Geophysics PAGEOPH (127) 627-639
Most large earthquakes of magnitude ???6.0 in California during 1852-1987 appear to show a southeast-to-northwest tendency of epicenter migration. This finding is consistent with earlier findings of Savage (1971) for a relatively few large earthquakes along the west coast of North America, and of Wood and Allen (1973) for smaller...
A late Wisconsinan marine incursion into Cape Cod Bay, Massachusetts
R. N. Oldale
1988, Quaternary Research (30) 237-250
Reinterpretation of seismic-reflection data from Cape Cod Bay has produced a revised late Wisconsinan history. Acoustically laminated deposits, originally inferred to be glaciolacustrine, are shown to be glaciomarine by tracing them to glaciomarine mud in Stellwagen Basin, north of Cape Cod Bay. A late Wisconsinan marine deposit of nonglacial origin...
Analytical approach to calculation of response spectra from seismological models of ground motion
Erdal Safak
1988, Earthquake Engineering and Structural Dynamics (16) 121-134
An analytical approach to calculate response spectra from seismological models of ground motion is presented. Seismological models have three major advantages over empirical models: (1) they help in an understanding of the physics of earthquake mechanisms, (2) they can be used to predict ground motions for future earthquakes and (3)...
General two‐point method for Determining velocity in open channel
John F. Walker
1988, Journal of Hydraulic Engineering (114) 801-805
The generally accepted procedure is to average velocity measurements at 0. 2D and 0. 8D, measured vertically from the water surface,or alternatively to measure velocity at a position equal to 0. 6D, where D is the total depth of flow. In some situations, one may wish to measure at depths...
The radiocarbon budget for Mono Lake: An unsolved mystery
W.S. Broecker, R. Wanninkhof, G. Mathieu, T.-H. Peng, S. Stine, S. Robinson, A. Herczeg, M. Stuiver
1988, Earth and Planetary Science Letters (88) 16-26
Since 1957 the 14C/C ratio of the dissolved inorganic carbon in Mono Lake has risen by about 60‰. The magnitude of this increase is about four times larger than that expected from the invasion of bomb-produced14C from the atmosphere. We have eliminated the following explanations: (1) measurement error, (2) an unusually...
Downslope Eulerian mean flow associated with high-frequency current fluctuations observed on the outer continental shelf and upper slope along the northeastern United States continental margin: Implications for sediment transport
B. Butman
1988, Continental Shelf Research (8) 811-840
Eulerian current measurements made 5-7 m above bottom at six stations along the United States east coast continental margin show a net downslope flow of 1-5 cm s-1. Although the scalar current speed decreases with water depth and toward the bottom, fluctuations in the cross-isobath flow were stronger and increasingly...
Wetland Boundary Determination in the Great Dismal Swamp Using Weighted Averages
Virginia Carter, Mary Keith Garrett, Patricia T. Gammon
1988, Water Resources Bulletin (24) 297-306
A weighted average method was used to analyze transition zone vegetation in the Great Dismal Swamp to determine if a more uniform determination of wetland boundaries can be made nationwide. The method was applied to vegetation data collected on four transects and three vertical layers across the wetland-to-upland transition zone...
Anomalous radiocarbon ages from a Holocene detrital organic lens in Alaska and their implications for radiocarbon dating and paleoenvironmental reconstructions in the arctic
R.E. Nelson, L. D. Carter, S.W. Robinson
1988, Quaternary Research (29) 66-71
Eleven radiocarbon age determinations clearly show that a lens of Holocene fluvial organic debris on the Alaskan Arctic Coastal Plain contains mostly pre-Holocene organic material. Radio-carbon ages of identified plant macrofossils indicate the material was deposited about 9000 to 9500 yr B.P. Radiocarbon analyses of bulk samples from this deposit,...
Stratigraphy and magnetic polarity of the high terrace remnants in the upper Ohio and Monongahela Rivers in West Virginia, Pennsylvania, and Ohio
R. B. Jacobson, D. P. Elston, John W. Heaton
1988, Quaternary Research (29) 216-232
A synthesis of previous work and new data on the stratigraphy of high terraces of the Ohio and Monongahela Rivers upstream from Parkersburg, West Virginia, indicates a correspondence between terrace histories in the ancient Teays and Pittsburgh drainage basins. Four terraces are identified in each. Sediments of the lower three...
The potential for catastrophic dam failure at Lake Nyos maar, Cameroon
J. P. Lockwood, J. E. Costa, M. L. Tuttle, J. Nni, S.G. Tebor
1988, Bulletin of Volcanology (50) 340-349
The upper 40 m of Lake Nyos is bounded on the north by a narrow dam of poorly consolidated pyroclastic rocks, emplaced during the eruptive formation of the Lake Nyos maar a few hundred years ago. This 50-m-wide natural dam is structurally weak and is being eroded at an uncertain,...
Distribution of selenium in soils of agricultural fields, western San Joaquin Valley, California
Roger Fujii, S. J. Deverel, D. B. Hatfield
1988, Soil Science Society of America Journal (52) 1274-1283
Soils from three agricultural fields in the Panoche Creek alluvial fan area in the western San Joaquin Valley, California, were analyzed for soluble, adsorbed, and total concentrations of selenium (Se) to assess the distribution and forms of Se in relation to the leaching of Se from soils. This assessment is...
Physical deposit measures and commercial potential: The case of titanium-bearing heavy-mineral deposits
E. D. Attanasi, J.H. DeYoung Jr.
1988, Mathematical Geology (20) 97-110
Physical measures of mineral deposit characteristics, such as grade and tonnage, long have been used in both subjective and analytic models to predict favorability of areas for the occurrence of mineral deposits of particular types. After a deposit has been identified, however, the explorationist must decide whether to continue data...
Columbia Bay, Alaska: An 'upside down' estuary
R. A. Walters, E.G. Josberger, C. L. Driedger
1988, Estuarine, Coastal and Shelf Science (26) 607-617
Circulation and water properties within Columbia Bay, Alaska, are dominated by the effects of Columbia Glacier at the head of the Bay. The basin between the glacier terminus and the terminal moraine (sill depth of about 22 m) responds as an ‘upside down’ estuary with the subglacial discharge of freshwater...
Marine petroleum source rocks and reservoir rocks of the Miocene Monterey Formation, California, U.S.A
C.M. Isaacs
1988, Book chapter, Petroleum resources of China and related subjects
The Miocene Monterey Formation of California, a biogenous deposit derived mainly from diatom debris, is important both as a petroleum source and petroleum reservoir. As a source, the formation is thought to have generated much of the petroleum in California coastal basins, which are among the most prolific oil provinces...
Interactions between seabirds and fisheries in the North Pacific Ocean
Linda L. Jones, Anthony R. DeGange
Joanna Burger, editor(s)
1988, Book chapter, Seabirds & other marine vertebrates: Competition, predation, and other interactions
Interactions between commercial fisheries and seabirds in the northern Pacific Ocean are increasing with rising consumption of fishery products. As fishing expands into remote areas previously not fished, additional populations of seabirds may be affected. Some interactions such as introduction of fish processing wastes into the environment may be beneficial...
Coarse-sediment bands on the inner shelf of southern Monterey Bay, California
R. E. Hunter, J.R. Dingler, R. J. Anima, B. M. Richmond
1988, Marine Geology (80) 81-98
Bands of coarse sand that trend parallel to the shore, unlike the approximately shore-normal bands found in many inner shelf areas, occur in southern Monterey Bay at water depths of 10–20 m, less than 1 km from the shore. The bands are 20–100 m wide and alternate with bands...
Effects of Precipitation and Land Use on Storm Runoff
R. G. Brown
1988, Water Resources Bulletin (24) 421-426
Storm-runoff quantity and quality were studied in three watersheds located near St. Paul in Ramsey County, Minnesota, from April 15 through September 15 of 1984, 1985, and 1986 to qualitatively determine the effects of precipitation and selected land uses on storm runoff. In respect to precipitation effects, differences in storm-runoff...
The growth of geological structures by repeated earthquakes: 2, Field examples of continental dip-slip faults
R.S. Stein, G.C.P. King, J. B. Rundle
1988, Journal of Geophysical Research Solid Earth (93) 13319-13331
A strong test of our understanding of the earthquake cycle is the ability to reproduce extant fault-bounded geological structures, such as basins and ranges, which are built by repeated cycles of deformation. Along strike-slip faults, the coseismic and interseismic deformation can be nearly equal in magnitude and opposite in sign,...
Origin and influence of coal mine drainage on streams of the United States
J. D. Powell
1988, Environmental Geology and Water Sciences (11) 141-152
Degradation of water quality related to oxidation of iron disulfide minerals associated with coal is a naturally occurring process that has been observed since the late seventeenth century, many years before commencement of commercial coal mining in the United States. Disturbing coal strata during mining operations accelerates this natural deterioration...
Vapor-dominated zones within hydrothermal systems: Evolution and natural state
S. E. Ingebritsen, M.L. Sorey
1988, Journal of Geophysical Research Solid Earth (93) 13635-13655
Three conceptual models illustrate the range of hydrothermal systems in which vapor-dominated conditions are found. The first model (model I) represents a system with an extensive near-vaporstatic vapor-dominated zone and limited liquid throughflow and is analogous to systems such as The Geysers, California. Such systems can evolve within low-permeability barriers...