P wave crustal velocity structure in the greater Mount Rainier area from local earthquake tomography
S.C. Moran, J.M. Lees, S. D. Malone
1999, Journal of Geophysical Research B: Solid Earth (104) 10775-10786
We present results from a local earthquake tomographic imaging experiment in the greater Mount Rainier area. We inverted P wave arrival times from local earthquakes recorded at permanent and temporary Pacific Northwest Seismograph Network seismographs between 1980 and 1996. We used a method similar to that described by Lees and Crosson [1989], modified to...
Multichannel analysis of surface waves
C.B. Park, R. D. Miller, J. Xia
1999, Geophysics (64) 800-808
The frequency‐dependent properties of Rayleigh‐type surface waves can be utilized for imaging and characterizing the shallow subsurface. Most surface‐wave analysis relies on the accurate calculation of phase velocities for the horizontally traveling fundamental‐mode Rayleigh wave acquired by stepping out a pair of receivers at intervals based on calculated ground roll...
Reactive solute transport in streams: A surface complexation approach for trace metal sorption
Robert L. Runkel, Briant A. Kimball, Diane M. McKnight, Kenneth E. Bencala
1999, Water Resources Research (35) 3829-3840
A model for trace metals that considers in-stream transport, metal oxide precipitation-dissolution, and pH-dependent sorption is presented. Linkage between a surface complexation submodel and the stream transport equations provides a framework for modeling sorption onto static and/or dynamic surfaces. A static surface (e.g., an iron- oxide-coated streambed) is defined as...
Inhibition of precipitation and aggregation of metacinnabar (mercuric sulfide) by dissolved organic matter isolated from the Florida Everglades
M. Ravichandran, G. R. Aiken, J. N. Ryan, M.M. Reddy
1999, Environmental Science & Technology (33) 1418-1423
Precipitation and aggregation of metacinnabar (black HgS) was inhibited in the presence of low concentrations (≥3 mg C/L) of humic fractions of dissolved organic matter (DOM) isolated from the Florida Everglades. At low Hg concentrations (≤5 × 10-8 M), DOM prevented the precipitation of metacinnabar. At moderate Hg...
Measurements of Reynolds stress profiles in unstratified tidal flow
M.T. Stacey, Stephen G. Monismith, J.R. Burau
1999, Journal of Geophysical Research C: Oceans (104) 10933-10949
In this paper we present a method for measuring profiles of turbulence quantities using a broadband acoustic doppler current profiler (ADCP). The method follows previous work on the continental shelf and extends the analysis to develop estimates of the errors associated with the estimation methods. ADCP data was collected in...
Crystal growth mechanisms in miarolitic cavities in the Lake George ring complex and vicinity, Colorado
D. E. Kile, D. D. Eberl
1999, American Mineralogist (84) 718-724
The Crystal Peak area of the Pikes Peak batholith, near Lake George in central Colorado, is world-renowned for its crystals of amazonite (the blue-green variety of microcline) and smoky quartz. Such crystals, collected from individual miarolitic pegmatites, have a remakably small variation in crystal size within each pegmatite, and the...
Environmental enrichment of brown capuchins (Cebus apella): Behavioral and plasma and fecal cortisol measures of effectiveness
S. Boinski, S.P. Swing, T. S. Gross, J.K. Davis
1999, American Journal of Primatology (48) 49-68
No consensus exists about the quantity and variety of environmental enrichment needed to achieve an acceptable level of psychological well-being among singly housed primates. Behavioral and plasma and fecal cortisol measures were used to evaluate the effectiveness of four levels of toy and foraging enrichment provided to eight wild-caught, singly...
Hydrated salt minerals on Europa's surface from the Galileo near-infrared mapping spectrometer (NIMS) investigation
T. B. McCord, G. B. Hansen, D. L. Matson, T. V. Johnson, J.K. Crowley, F. P. Fanale, R. W. Carlson, W. D. Smythe, P. D. Martin, C. A. Hibbitts, J. C. Granahan, A. Ocampo
1999, Journal of Geophysical Research E: Planets (104) 11827-11851
We reported evidence of heavily hydrated salt minerals present over large areas of Europa's surface from analysis of reflectance spectra returned by the Galileo mission near infrared mapping spectrometer (NIMS) [McCord et al., 1997a, b, 1998a, b]. Here we elaborate on this earlier evidence, present spatial distributions of these minerals,...
UCODE, a computer code for universal inverse modeling
E. P. Poeter, M. C. Hill
1999, Computers & Geosciences (25) 457-462
This article presents the US Geological Survey computer program UCODE, which was developed in collaboration with the US Army Corps of Engineers Waterways Experiment Station and the International Ground Water Modeling Center of the Colorado School of Mines. UCODE performs inverse modeling, posed as a parameter-estimation problem, using nonlinear regression....
Air blasts generated by rockfall impacts: Analysis of the 1996 Happy Isles event in Yosemite National Park
M.M. Morrissey, W. Z. Savage, G. F. Wieczorek
1999, Journal of Geophysical Research B: Solid Earth (104) 23189-23198
The July 10, 1996, Happy Isles rockfall in Yosemite National Park, California, released 23,000 to 38,000 m3 of granite in four separate events. The impacts of the first two events which involved a 550-m free fall, generated seismic waves and atmospheric pressure waves (air blasts). We focus on the dynamic behavior...
Evaluating sediment chemistry and toxicity data using logistic regression modeling
L.J. Field, D.D. MacDonald, S.B. Norton, C.G. Severn, C.G. Ingersoll
1999, Environmental Toxicology and Chemistry (18) 1311-1322
This paper describes the use of logistic-regression modeling for evaluating matching sediment chemistry and toxicity data. Contaminant- specific logistic models were used to estimate the percentage of samples expected to be toxic at a given concentration. These models enable users to select the probability of effects of concern corresponding to...
An ancient depleted mantle sample from a 42-Ma dike in Montana: Constraints on persistence of the lithosphere during Eocene Magmatism
F.O. Dudas, S. S. Harlan
1999, Journal of Geology (107) 287-299
Recent models for the Cenozoic tectonic evolution of the western margin of North America propose that delamination of ancient lithosphere accompanied asthenospheric upwelling, magmatism, and uplift subsequent to Laramide deformation. On the basis of the age of an alkaline dike in south-central Montana, thermometry of mantle xenoliths from the dike,...
Development of San Leandro synform and neotectonics of the San Francisco Bay block, California
M. S. Marlow, R.C. Jachens, P. E. Hart, P.R. Carlson, R. J. Anima, J.R. Childs
1999, Marine and Petroleum Geology (16) 431-442
High-resolution, 24-channel seismic-reflection data show a stratified synform beneath south San Francisco Bay. These seismic-reflection data reveal an eastward-dipping bedrock surface that is about 40 m deep (subbottom) beneath the western south bay, and that reaches a maximum observed depth of 500-800 m (subbottom) below the eastern half of the...
Formation of natural gas hydrates in marine sediments 1. Conceptual model of gas hydrate growth conditioned by host sediment properties
M. B. Clennell, M. Hovland, J.S. Booth, P. Henry, W.J. Winters
1999, Journal of Geophysical Research B: Solid Earth (104) 22985-23003
The stability of submarine gas hydrates is largely dictated by pressure and temperature, gas composition, and pore water salinity. However, the physical properties and surface chemistry of deep marine sediments may also affect the thermodynamic state, growth kinetics, spatial distributions, and growth forms of clathrates. Our conceptual model presumes that...
Cooling rates and crystallization dynamics of shallow level pegmatite-aplite dikes, San Diego County, California
Karen L. Webber, William B. Simmons, Alexander U. Falster, Eugene E. Foord
1999, American Mineralogist (84) 708-717
Pegmatites of the Pala and Mesa Grande Pegmatite Districts, San Diego County, California are typically thin, sheet-like composite pegmatite-aplite dikes. Aplitic portions of many dikes display pronounced mineralogical layering referred to as "line rock," characterized by fine-grained, garnet-rich bands alternating with albite- and quartz-rich bands. Thermal modeling was performed for...
Processes governing phytoplankton blooms in estuaries. I: The local production-loss balance
L.V. Lucas, Jeffrey R. Koseff, J. E. Cloern, Stephen G. Monismith, J.K. Thompson
1999, Marine Ecology Progress Series (187) 1-15
The formation and spatial distribution of phytoplankton blooms in estuaries are controlled by (1) local mechanisms, which determine the production-loss balance for a water column at a particular spatial location (i.e. control if a bloom is possible), and (2) transport-related mechanisms, which govern biomass distribution (i.e. control if and where...
Bird communities of natural and modified habitats in Panama
L. J. Petit, D. R. Petit, D. G. Christian, Hugo D. W. Powell
1999, Ecography (22) 292-304
Only a small proportion of land can realistically be protected as nature reserves and thus conservation efforts also must focus on the ecological value of agroecosystems and developed areas surrounding nature reserves. In this study, avian communities were surveyed in 11 habitat types in central Panama, across a gradient from...
Historical trends in salinity and substrate in central Florida Bay: A paleoecological reconstruction using modern analogue data
G. L. Brewster-Wingard, S. E. Ishman
1999, Estuaries (22) 369-383
Understanding the natural spatial and temporal variability that exists within an ecosystem is a critical component of efforts to restore systems to their natural state. Analysis of benthic foraminifers and molluscs from modern monitoring sites within Florida Bay allows us to determine what environmental parameters control spatial and temporal variability...
Modeling impact of storage zones on stream dissolved oxygen
S.C. Chapra, R.L. Runkel
1999, Journal of Environmental Engineering (125) 415-419
The Streeter-Phelps dissolved oxygen model is modified to incorporate storage zones. A dimensionless number reflecting enhanced decomposition caused by the increased residence time of the biochemical oxygen demand in the storage zone parameterizes the impact. This result provides a partial explanation for the high decomposition rates observed in shallow streams....
Paleomagnetism of an east-west transect across the Cascade arc in southern Washington: Implications for regional tectonism
J.T. Hagstrum, D. A. Swanson, R.C. Evarts
1999, Journal of Geophysical Research B: Solid Earth (104) 12853-12863
Paleomagnetic data from a transect across the Cascade arc in southern Washington were collected to test models of vertical axis rotations for this part of the Pacific Northwest and to provide information on the tectonic history of the St. Helens seismic zone. The 75 site-mean directions are divided into three...
Surface faulting and paleoseismic history of the 1932 Cedar Mountain earthquake area, west-central Nevada, and implications for modern tectonics of the Walker Lane
J. W. Bell, C.M. DePolo, A. R. Ramelli, A.M. Sarna-Wojcicki, C.E. Meyer
1999, Geological Society of America Bulletin (111) 791-807
The 1932 Cedar Mountain earthquake (Ms 7.2) was one of the largest historical events in the Walker Lane region of western Nevada, and it produced a complicated strike-slip rupture pattern on multiple Quaternary faults distributed through three valleys. Primary, right-lateral surface ruptures occurred on north-striking faults in Monte Cristo Valley;...
Relationships between peak ground acceleration, peak ground velocity, and Modified Mercalli Intensity in California
David J. Wald, Vincent Quitoriano, Thomas H. Heaton, Hiroo Kanamori
1999, Earthquake Spectra (15) 557-564
We have developed regression relationships between Modified Mercalli Intensity (Imm) and peak ground acceleration (PGA) and velocity (PGV) by comparing horizontal peak ground motions to observed intensities for eight significant California earthquakes. For the limited range of Modified Mercalli intensities (Imm), we find that for peak acceleration with...
Dissolved sulfide distributions in the water column and sediment pore waters of the Santa Barbara Basin
J.S. Kuwabara, A. VanGeen, D.C. McCorkle, J.M. Bernhard
1999, Geochimica et Cosmochimica Acta (63) 2199-2209
Dissolved sulfide concentrations in the water column and in sediment pore waters were measured by square-wave voltammetry (nanomolar detection limit) during three cruises to the Santa Barbara Basin in February 1995, November–December 1995, and April 1997. In the water column, sulfide concentrations measured outside...
Potential impacts on Colorado Rocky Mountain weather due to land use changes on the adjacent Great Plains
T.N. Chase, R.A. Pielke Sr., T.G.F. Kittel, Jill Baron, T.J. Stohlgren
1999, Journal of Geophysical Research D: Atmospheres (104) 16673-16690
Evidence from both meteorological stations and vegetational successional studies suggests that summer temperatures are decreasing in the mountain-plain system in northeast Colorado, particularly since the early 1980s. These trends are coincident with large changes in regional land cover. Trends in global, Northern Hemisphere and continental surface temperatures over the same...
The sensitivity of terrestrial carbon storage to historical climate variability and atmospheric CO2 in the United States
H. Tian, J. M. Melillo, D. W. Kicklighter, A. D. McGuire, J. Helfrich
1999, Tellus, Series B: Chemical and Physical Meteorology (51) 414-452
We use the Terrestrial Ecosystem Model (TEM, Version 4.1) and the land cover data set of the international geosphere-biosphere program to investigate how increasing atmospheric CO2 concentration and climate variability during 1900-1994 affect the carbon storage of terrestrial ecosystems in the conterminous USA, and how carbon storage has been affected...
