Faulting caused by groundwater level declines, San Joaquin Valley, California
Thomas L. Holzer
1980, Water Resources Research (16) 1065-1070
Approximately 230 mm of aseismic vertical offset of the land surface across the Pond-Poso Creek fault in the San Joaquin Valley, California, probably is related to groundwater withdrawal for crop irrigation. The scarp is approximately 3.4 km long and occurs in an area where the land subsided more than 1.5...
Computational methods for inverse problems in geophysics: Inversion of travel time observations
V. Pereyra, H.B. Keller, W.H.K. Lee
1980, Physics of the Earth and Planetary Interiors (21) 120-125
General ways of solving various inverse problems are studied for given travel time observations between sources and receivers. These problems are separated into three components: (a) the representation of the unknown quantities appearing in the model; (b) the nonlinear least-squares problem; (c) the direct, two-point ray-tracing problem used to compute...
Tertiary δ18O record and glacio-eustatic sea-level fluctuations
R.K. Matthews, R.Z. Poore
1980, Geology (8) 501-504
Previous interpretation of the Tertiary δ18O record of plaiiktic and benthic foraminifers has emphasized comparison to the modern ocean, assumed an ice-free world prior to middle Miocene time, and thereby calculated surprisingly cool temperatures for the tropical sea surface. We propose an alternative...
Modern and ancient submarine fans: Discussion of papers by Walker and Normark.
Tor H. Nilsen
1980, American Association of Petroleum Geologists Bulletin (64) 1094-1101
No abstract available....
Rate of mercury loss from contaminated estuarine sediments
Michael H. Bothner, R.A. Jahnke, M. L. Peterson, R. Carpenter
1980, Geochimica et Cosmochimica Acta (44) 273-285
The concentration of mercury in contaminated estuarine sediments of Bellingham Bay, Washington was found to decrease with a half-time of about 1.3 yr after the primary anthropogenic source of mercury was removed. In situ measurements of the mercury flux from sediments, in both dissolved and volatile forms, could not account...
Ocean eddy structure by satellite radar altimetry required for iceberg towing
W. J. Campbell, R. E. Cheney, J. G. Marsh, N. M. Mognard
1980, Cold Regions Science and Technology (1) 211-221
Models for the towing of large tabular icebergs give towing speeds of 0.5 knots to 1.0 knots relative to the ambient near surface current. Recent oceanographic research indicates that the world oceans are not principally composed of large steady-state current systems, like the Gulf Stream, but that most of the...
Implications of regional gravity for state of stress in the earth's crust and upper mantle
M. McNutt
1980, Journal of Geophysical Research Solid Earth (85) 6377-6396
Topography is maintained by stress differences within the earth. Depending on the distribution of the stress we classify the support as either local or regional compensation. In general, the stresses implied in a regional compensation scheme are an order of magnitude larger than those corresponding to local isostasy. Gravity anomalies,...
Nd-isotopes in selected mantle-derived rocks and minerals and their implications for mantle evolution
A. R. Basu, M. Tatsumoto
1980, Contributions to Mineralogy and Petrology (75) 43-54
The Sm-Nd systematics in a variety of mantle-derived samples including kimberlites, alnoite, carbonatite, pyroxene and amphibole inclusions in alkali basalts and xenolithic eclogites, granulites and a pyroxene megacryst in kimberlites are reported. The additional data on kimberlites strengthen our earlier conclusion that kimberlites are derived from a relatively undifferentiated chondritic...
Circular current loops, magnetic dipoles and spherical harmonic analysis.
L.R. Alldredge
1980, Journal of Geomagnetism & Geoelectricity (32) 357-364
Spherical harmonic analysis (SHA) is the most used method of describing the Earth's magnetic field, even though spherical harmonic coefficients (SHC) almost completely defy interpretation in terms of real sources. Some moderately successful efforts have been made to represent the field in terms of dipoles placed in the core in...
Speculations on processes responsible for mesoscale current lineations on the continental shelf, southern California
Herman A. Karl
1980, Marine Geology (34) M9-M18
A side-scan sonar survey of San Pedro shelf, California, reveals areas of mesoscale current lineations oriented approximately north-northeast in water depths of 20-25 m. Widths of sand ribbons range from 40 to 120 m and intervening erosional furrows, from 15 to 50 m. A conceptual model shows that the scale...
Mixing models and ionic geothermometers applied to warm (up to 60°C) springs: Jordan Rift Valley, Israel
E. Mazor, D. Levitte, A.H. Truesdell, J. Healy, A. Nissenbaum
1980, Journal of Hydrology (45) 1-19
Mixing models and evaluation of SiO2 contents of warm-water manifestations in the Jordan—Dead Sea Rift Valley indicate that these waters are fed by aquifers with estimated temperatures of up to 68°C. These calculations and Na/K ratios, concentrations of Na, K and Ca, concentrations of atmospheric Ne, Ar, Kr and Xe;...
Trace metal bioavailability: Modeling chemical and biological interactions of sediment-bound zinc
S. N. Luoma, G.W. Bryan
Everett A. Jenne, editor(s)
1979, Book chapter, Chemical Modeling in Aqueous Systems
Extractable concentrations of sediment-bound Zn, as modified by the physicochemical form of the metal in the sediments, controlled Zn concentrations in the deposit-feeding bivalvesScrobicularia plana (collected from 40 stations in 17 estuaries in southwest England) andMacoma balthica (from 28 stations in San Francisco Bay). Over a wide range of concentrations,...
A digital model for simulation of ground-water hydrology in the Houston area, Texas
Walter R. Meyer, Jerry E. Carr
1979, Limited Printing Report 103
This report documents the construction and calibration of a digital model for the simulation of hydrologic conditions in the Chicot and Evangeline aquifers in the Houston area of southeastern Texas. The model is a five-layer finite-difference model, with a grid pattern of 63 x 67 nodes representing an area of...
Water quality of Livingston Reservoir on the Trinity River, southeastern Texas
Jack Rawson
1979, Texas Department of Water Resources Report 230
The concentrations of dissolved solids, chloride, and sulfate in Livingston Reservoir on the Trinity River in southeastern Texas usually average less than 250 mg/l (milligrams per liter), 40 mg/l, and 50 mg/l, respectively. The water is usually hard or moderately hard (61 to 180 mg/l as calcium carbonate). The concentrations...
Preliminary summary of the U.S. Geological Survey strong-motion records from the October 15, 1979 Imperial Valley earthquake
R. L. Porcella, R.B. Matthiesen
1979, Open-File Report 79-1654
This report summarizes the data from near-in strong-motion accelerograph stations operated by the U.S. Geological Survey in the Imperial Valley of California at the time of the October 15, 1979 Imperial Valley earthquake. The purpose of this report is to alert others as to the nature of the strong-motion data...
Diet-related die-off of captive black-crowned night herons
J. W. Carpenter, J. W. Spann, M.N. Novilla
1979, American Association of Zoo Veterinarians, Annual Proceedings (1979) 51-55
Several species of herons, which are top-level consumers in aquatic food chains, have experienced population declines in certain areas o f their normal range (7,13) -- areas in which elevated levels of various environmental pollutants are known to occur. (6) To determine the effects of environmental contaminants on the Ardeidae,...
Population ecology of house mice in unstable habitats
L.F. Stickel
1979, Journal of Animal Ecology (48) 871-887
(1) The relationships between habitat change and house mouse populations were studied by monthly live trapping in a corn-wheat-hay rotation on a small Maryland farm. (2) Population density reached 53.0/ha in a wheat/hay field in October and 25.4/ha in corn in September. Populations increased by immigration as wheat or corn...
Mathematical models and population cycles: A critical evaluation of a recent modeling effort
J.D. Nichols, J.B. Hestbeck, W. Conley
1979, Journal of Mathematical Biology (8) 259-263
No abstract available....
Seasonal occurrence and distribution of submerged aquatic macrophytes in the tidal Potomac River
G.M. Haramis, V. Carter, P. Gammon, C. Hupp
1979, Book chapter, Seminar on water quality in the tidal Potomac River, December 1978
A systematic survey was conducted in the Tidal Potomac River in 1978 to determine the presence, abundance, and phenology of submersed aquatic macrophytes. The survey covered 81.5 km of main river and 59.3 km of tributary on the Maryland shore. Four regions were selected for the study: (1)...
Bird communities associated with succession and management of lowland conifer forests
D.K. Dawson
1979, Book chapter, Management of North Central and Northeastern Forests for Nongame Birds, Proceedings of the Workshop
Data from published bird censuses were used to determine changes in avian communities in relation to plant succession, fire, type conversion, and timber management practices in lowland conifer forests in the northeastern United States. With modifications in current logging practices, habitat for the bird species that nest in undisturbed...
Volcanic ash in surficial sediments of the Kodiak shelf - An indicator of sediment dispersal patterns
M. A. Hampton, A.H. Bouma, T. P. Frost, I.P. Colburn
1979, Marine Geology (29) 347-356
Surficial sediments of the Kodiak shelf, Gulf of Alaska, contain various amounts of volcanic ash whose physical properties indicate that it originated from the 1912 Katmai eruption. The distribution of ash is related to the shelf physiography and represents redistribution by oceanic circulation rather than the original depositional pattern from...
A radiographic scanning technique for cores
G. W. Hill, M.E. Dorsey, J.C. Woods, R. J. Miller
1979, Marine Geology (29) 93-106
A radiographic scanning technique (RST) can produce single continuous radiographs of cores or core sections up to 1.5 m long and up to 30 cm wide. Changing a portable industrial X-ray unit from the normal still-shot mode to a scanning mode requires simple, inexpensive, easily constructed, and highly durable equipment....
Small-scale slump deposits, Middle Atlantic Continental Slope, off eastern United States
H.J. Knebes, Bobb Carson
1979, Marine Geology (29) 221-236
Analyses of 24 high-resolution seismic-reflection profiles that were collected during local and regional surveys show that small-scale slump deposite are ubiquitous whthin the intercanyon areas of the Continental Slope of the Middle Atlantic Bight. The deposits involve the upper 10-90 m of sediments, extend downslops for 1.8-7.2 km, and are...
On the mechanical interaction between a fluid-filled fracture and the earth's surface
David D. Pollard, Gary Holzhausen
1979, Tectonophysics (53) 27-57
The mechanical interaction between a fluid-filled fracture (e.g., hydraulic fracture joint, or igneous dike) and the earth's surface is analyzed using a two-dimensional elastic solution for a slit of arbitrary inclination buried beneath a horizontal free surface and subjected to an arbitrary pressure distribution. The solution is obtained by...
A comparison of long-baseline strain data and fault creep records obtained near Hollister, California
L.E. Slater, Robert O. Burford
1979, Tectonophysics (52) 481-496
A comparison of creepmeter records from nine sites along a 12-km segment of the Calaveras fault near Hollister, California and long-baseline strain changes for nine lines in the Hollister multiwavelength distance-measuring (MWDM) array has established that episodes of large-scale deformation both preceded and accompanied periods of creep activity monitored along...
