Relationships between salt marsh loss and dredged canals in three Louisiana Estuaries
A.S. Bass, R.E. Turner
1997, Journal of Coastal Research (13) 895-903
Coastal land loss rates were quantified for 27 salt marshes in three estuaries of the Louisiana Mississippi Deltaic plain: Barataria, Terrebonne and St. Bernard. The sites ranged from 23 ha to 908 ha and the total area of all sites was 6,367 ha. Two methods were used to calculate open...
Continents as lithological icebergs: The importance of buoyant lithospheric roots
D.H. Abbott, R. Drury, Walter D. Mooney
1997, Earth and Planetary Science Letters (149) 15-27
An understanding of the formation of new continental crust provides an important guide to locating the oldest terrestrial rocks and minerals. We evaluated the crustal thicknesses of the thinnest stable continental crust and of an unsubductable oceanic plateau and used the...
Accelerated relative sea-level rise and rapid coastal erosion: Testing a causal relationship for the Louisiana barrier islands
J. H. List, A. H. Sallenger Jr., M. E. Hansen, B. E. Jaffe
1997, Marine Geology (140) 347-365
The role of relative sea-level rise as a cause for the rapid erosion of Louisiana's barrier island coast is investigated through a numerical implementation of a modified Bruun rule that accounts for the low percentage of sand-sized sediment in the eroding Louisiana shoreface. Shore-normal profiles from 150 km of coastline...
Climatic controls of western U.S. glaciers at the last glacial maximum
S. W. Hostetler, P.U. Clark
1997, Quaternary Science Reviews (16) 505-511
We use a nested atmospheric modeling strategy to simulate precipitation and temperature of the western United States 18,000 years ago (18 ka). The high resolution of the nested model allows us to isolate the regional structure of summer temperature and winter precipitation that is crucial to determination of the net...
A dynamic balance between magma supply and eruption rate at Kilauea volcano, Hawaii
R.P. Denlinger
1997, Journal of Geophysical Research B: Solid Earth (102) 18091-18100
The dynamic balance between magma supply and vent output at Kilauea volcano is used to estimate both the volume of magma stored within Kilauea volcano and its magma supply rate. Throughout most of 1991 a linear decline in volume flux from the Kupaianaha vent on Kilauea's east rift zone was...
Use of geochemical mass balance modelling to evaluate the role of weathering in determining stream chemistry in five mid-Atlantic watersheds on different lithologies
Anne K. O’Brien, Karen C. Rice, Owen P. Bricker, Margaret M. Kennedy, R. Todd Anderson
1997, Hydrological Processes (11) 719-744
The importance of mineral weathering was assessed and compared for five mid-Atlantic watersheds receiving similar atmospheric inputs but underlain by differing bedrock. Annual solute mass balances and volume-weighted mean solute concentrations were calculated for each watershed for each year of record. In addition, primary and secondary mineralogy were determined for...
Roadblocks on the kill curve: Testing the Raup hypothesis
C. W. Poag
1997, Palaios (12) 582-590
The documented presence of two large (~100-km diameter), possibly coeval impact craters of late Eocene age, requires modification of the impact-kill curve proposed by David M. Raup. Though the estimated meteorite size for each crater alone is large enough to have produced considerable global environmental stress, no horizons of mass...
Constant-concentration boundary condition: Lessons from the HYDROCOIN variable-density groundwater benchmark problem
Leonard F. Konikow, W. E. Sanford, P.J. Campbell
1997, Water Resources Research (33) 2253-2261
In a solute-transport model, if a constant-concentration boundary condition is applied at a node in an active flow field, a solute flux can occur by both advective and dispersive processes. The potential for advective release is demonstrated by reexamining the Hydrologic Code Intercomparison (HYDROCOIN) project case 5 problem, which represents...
Using δ87Sr values to identify sources of salinity to a freshwater aquifer, Greater Aneth Oil Field, Utah, USA
D. L. Naftz, Z. E. Peterman, L.E. Spangler
1997, Chemical Geology (141) 195-209
Salinity increases in water from the freshwater Navajo aquifer in the Aneth area have been documented in recent years. Previous studies during the 1980s in the Aneth area suggested that brines associated with oil production and their subsequent re-injection were the probable source of salinity in the Navajo aquifer. Differences...
Methods for predicting peak discharge of floods caused by failure of natural and constructed earthen dams
Joseph S. Walder, Jim E. O'Connor
1997, Water Resources Research (33) 2337-2348
Floods from failures of natural and constructed dams constitute a widespread hazard to people and property. Expeditious means of assessing flood hazards are necessary, particularly in the case of natural dams, which may form suddenly and unexpectedly. We revise statistical relations (derived from data for past constructed and natural dam...
Non-double-couple earthquake mechanisms at the Hengill-Grensdalur volcanic complex, southwest Iceland
B.R. Julian, A.D. Miller, G.R. Foulger
1997, Geophysical Research Letters (24) 743-746
The Hengill-Grensdalur area in Iceland generates frequent small non-double-couple earthquakes with explosive volumetric components. We collected high quality three-component digital recordings of 4,000 earthquakes on a purpose-designed, 32-station network in 1991, and determined focal mechanisms for 100 of the best-recorded earthquakes by inverting amplitude ratios. Many...
The Osceola Mudflow from Mount Rainier: Sedimentology and hazard implications of a huge clay-rich debris flow
J.W. Vallance, K. M. Scott
1997, Geological Society of America Bulletin (109) 143-163
The 3.8 km3 Osceola Mudflow began as a water-saturated avalanche during phreatomagmatic eruptions at the summit of Mount Rainier about 5600 years ago. It filled valleys of the White River system north and northeast of Mount Rainier to depths of more than 100 m, flowed northward and westward more than 120...
Practical use of video imagery in nearshore oceanographic field studies
K. T. Holland, R.A. Holman, T.C. Lippmann, J. Stanley, N. Plant
1997, IEEE Journal of Oceanic Engineering (22) 81-91
An approach was developed for using video imagery to quantify, in terms of both spatial and temporal dimensions, a number of naturally occurring (nearshore) physical processes. The complete method is presented, including the derivation of the geometrical relationships relating image and ground coordinates, principles to be considered when working with...
Gillnet selectivity for lake trout (Salvelinus namaycush) in Lake Superior
Michael J. Hansen, Charles P. Madenjian, James H. Selgeby, Thomas E. Helser
1997, Canadian Journal of Fisheries and Aquatic Sciences (54) 2483-2490
Gillnet selectivity for lake trout (Salvelinus namaycush) was estimated indirectly from catches in nets of 102-, 114-, 127-, 140-, and 152-mm stretch measure. Mesh selectivity was modeled as a nonlinear response surface that describes changes in the mean, standard deviation, and skewness of fish lengths across mesh sizes. Gillnet selectivity...
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...
Diverse primitive magmas in the Cascade arc, Northern Oregon and Southern Washington
R. M. Conrey, D. R. Sherrod, P. R. Hooper, D. A. Swanson
1997, Canadian Mineralogist (35) 367-396
Bulk-rock major- and trace-element composition, petrography and mineral compositions are presented for a diverse suite of 22 primitive mafic lavas in the Cascade Range of northern Oregon and southern Washington. With the exception of an early Western Cascade basalt, all the rocks are younger than 7 Ma. Intensive parameters [F(H2O),...
Temperature effects on stocks and stability of a phytoplankton-zooplankton model and the dependence on light and nutrients
J. Norberg, D.L. DeAngelis
1997, Ecological Modelling (95) 75-86
A model of a closed phytoplankton—zooplankton ecosystem was analyzed for effects of temperature on stocks and stability and the dependence of these effects on light and total nutrient concentration of the system. An analysis of the steady state equations showed that the effect of temperature on zooplankton and POM biomass...
Predicting the probability of elevated nitrate concentrations in the Puget Sound Basin: Implications for aquifer susceptibility and vulnerability
A. J. Tesoriero, F.D. Voss
1997, Ground Water (35) 1029-1039
The occurrence and distribution of elevated nitrate concentrations (≥ 3 mg/l) in ground water in the Puget Sound Basin, Washington, were determined by examining existing data from more than 3000 wells. Models that estimate the probability that a well has an elevated nitrate concentration were constructed by relating the occurrence...
Complexities of plinian fall deposition at vent: An example from the 1912 Novarupta eruption (Alaska)
J. Fierstein, Bruce F. Houghton, C. J. N. Wilson, W. Hildreth
1997, Journal of Volcanology and Geothermal Research (76) 215-227
An extremely proximal ejecta ring, with exposures to within 100 m of vent, was deposited during later-stage plinian fall activity during the 1912 Novarupta eruption in Alaska. One bed in the ejecta ring (bed S) contains predominantly andesitic clasts which serve to delineate the striking contrast in thinning rates along...
Transient triggering of near and distant earthquakes
J. Gomberg, M.L. Blanpied, N.M. Beeler
1997, Bulletin of the Seismological Society of America (87) 294-309
We demonstrate qualitatively that frictional instability theory provides a context for understanding how earthquakes may be triggered by transient loads associated with seismic waves from near and distance earthquakes. We assume that earthquake triggering is a stick-slip process and test two hypotheses about the effect of transients on the timing...
The Chesapeake Bay bolide impact: A convulsive event in Atlantic Coastal Plain evolution
C. Wylie Poag
1997, Sedimentary Geology (108) 45-90
Until recently, Cenozoic evolution of the Atlantic Coastal Plain has been viewed as a subcyclical continuum of deposition and erosion. Marine transgressions alternated with regressions on a slowly subsiding passive continental margin, their orderly succession modified mainly by isostatic adjustments, occasional Appalachian tectonism, and paleoclimatic change. This passive scenario was...
Stratigraphy and structure of the Sevier thrust belt and proximal foreland-basin system in central Utah: A transect from the Sevier Desert to the Wasatch Plateau
T.F. Lawton, D. A. Sprinkel, P.G. Decelles, G. Mitra, A.J. Sussman, M. P. Weiss
1997, Brigham Young University Geology Studies (42) 33-67
The Sevier orogenic belt in central Utah comprises four north-northwest trending thrust plates and two structural culminations that record crustal shortening and uplift in late Mesozoic and early Tertiary time. Synorogenic clastic rocks, mostly conglomerate and sandstone, exposed within the thrust belt were deposited in wedge-top and foredeep depozones within...
Comparative sensitivity of Selenastrum capricornutum and Lemna minor to sixteen herbicides
J.F. Fairchild, D. S. Ruessler, P.S. Haverland, A.R. Carlson
1997, Archives of Environmental Contamination and Toxicology (32) 353-357
Aquatic plant toxicity tests are frequently conducted in environmental risk assessments to determine the potential impacts of contaminants on primary producers. An examination of published plant toxicity data demonstrates that wide differences in sensitivity can occur across phylogenetic groups of plants. Yet relatively few studies have been conducted with the...
Factors controlling threshold friction velocity in semiarid and arid areas of the United States
Beatrice Marticorena, G. Bergametti, Jayne Belnap
1997, Journal of Geophysical Research (102) 23,277-23,287
A physical model was developed to explain threshold friction velocities u*t for particles of the size 60a??120 I?m lying on a rough surface in loose soils for semiarid and arid parts of the United States. The model corrected for the effect of momentum absorption by the nonerodible roughness. For loose...
Distribution of black-tailed jackrabbit habitat determined by GIS in southwestern Idaho
Steven T. Knick, D.L. Dyer
1997, Journal of Wildlife Management (61) 75-85
We developed a multivariate description of black-tailed jackrabbit (Lepus californicus) habitat associations from Geographical Information Systems (GIS) signatures surrounding known jackrabbit locations in the Snake River Birds of Prey National Conservation Area (NCA), in southwestern Idaho. Habitat associations were determined for characteristics within a 1-km radius (approx home range size)...
