Postearthquake relaxation and aftershock accumulation linearly related after the 2003 M 6.5 Chengkung, Taiwan, and the 2004 M 6.0 Parkfield, California, earthquakes
J.C. Savage, S.-B. Yu
2007, Bulletin of the Seismological Society of America (97) 1632-1645
We treat both the number of earthquakes and the deformation following a mainshock as the superposition of a steady background accumulation and the postearthquake process. The preseismic displacement and seismicity rates ru and rE are used as estimates of the background rates. Let t be the time after the...
Investigation of magnesium isotope fractionation during basalt differentiation: Implications for a chondritic composition of the terrestrial mantle
F.-Z. Teng, M. Wadhwa, Rosalind T. Helz
2007, Earth and Planetary Science Letters (261) 84-92
To investigate whether magnesium isotopes are fractionated during basalt differentiation, we have performed high-precision Mg isotopic analyses by multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) on a set of well-characterized samples from Kilauea Iki lava lake, Hawaii, USA. Samples from the Kilauea Iki...
Summer microhabitat use of fluvial bull trout in Eastern Oregon streams
R. Al-Chokhachy, P. Budy
2007, North American Journal of Fisheries Management (27) 1068-1081
The management and recovery of populations of bull trout Salvelinus confluentus requires a comprehensive understanding of habitat use across different systems, life stages, and life history forms. To address these needs, we collected microhabitat use and availability data in three fluvial populations of bull trout in eastern Oregon. We evaluated...
Physically based estimation of soil water retention from textural data: General framework, new models, and streamlined existing models
John R. Nimmo, William N. Herkelrath, Luna Laguna
2007, Vadose Zone Journal (6) 766-773
Numerous models are in widespread use for the estimation of soil water retention from more easily measured textural data. Improved models are needed for better prediction and wider applicability. We developed a basic framework from which new and existing models can be derived to facilitate improvements. Starting from the assumption...
In situ time-series measurements of subseafloor sediment properties
R. A. Wheatcroft, A.W. Stevens, R.V. Johnson
2007, IEEE Journal of Oceanic Engineering (32) 862-871
The capabilities and diversity of subsurface sediment sensors lags significantly from what is available for the water column, thereby limiting progress in understanding time-dependent seabed exchange and high-frequency acoustics. To help redress this imbalance, a new instrument, the autonomous sediment profiler (ASP), is described herein....
Implementing regional sediment management to sustain navigation at an energetic tidal inlet
H.R. Moritz, G.R. Gelfenbaum, G. M. Kaminsky, P. Ruggiero, J. Oltman-shay, D.J. Mckillip
2007, Conference Paper, Coastal Sediments '07 - Proceedings of 6th International Symposium on Coastal Engineering and Science of Coastal Sediment Processes
Regional Sediment Management (RSM) is a systems-based approach for managing multiple projects involving sediment. RSM fosters balance between infrastructure and natural system processes, resulting in reduced project costs and achievement of greater benefits. This paper introduces the RSM concept and describes how RSM is being implemented at the Mouth of...
Amphibian populations in the terrestrial environment: Is there evidence of declines of terrestrial forest amphibians in northwestern California?
H.H. Welsh Jr., G. M. Fellers, A.J. Lind
2007, Journal of Herpetology (41) 469-482
Amphibian declines have been documented worldwide; however the vast majority are species associated with aquatic habitats. Information on the status and trends of terrestrial amphibians is almost entirely lacking. Here we use data collected across a 12-yr period (sampling from 1984-86 and from 1993-95) to address the question of whether...
Study of a prehistoric landslide using seismic reflection methods integrated with geological data in the Wasatch Mountains, Utah, USA
B.E. Tingey, J.H. McBride, T.J. Thompson, W. J. Stephenson, J.V. South, M. Bushman
2007, Engineering Geology (95) 1-29
An integration of geological and geophysical techniques characterizes the internal and basal structure of a landslide along the western margin of the Wasatch Mountains in northern Utah, USA. The study area is within a region of planned and continuing residential development. The Little Valley Landslide is a prehistoric landslide as...
Linking resources with demography to understand resource limitation for bears
M. J. Reynolds-Hogland, L.B. Pacifici, M.S. Mitchell
2007, Journal of Applied Ecology (44) 1166-1175
1. Identifying the resources that limit growth of animal populations is essential for effective conservation; however, resource limitation is difficult to quantify. Recent advances in geographical information systems (GIS) and resource modelling can be combined with demographic modelling to yield insights into resource limitation. 2. Using long-term data on a...
Effects of earlier sea ice breakup on survival and population size of polar bears in western Hudson Bay
E.V. Regehr, N.J. Lunn, Steven C. Amstrup, I. Stirling
2007, Journal of Wildlife Management (71) 2673-2683
Some of the most pronounced ecological responses to climatic warming are expected to occur in polar marine regions, where temperature increases have been the greatest and sea ice provides a sensitive mechanism by which climatic conditions affect sympagic (i.e., with ice) species. Population-level effects of climatic change, however, remain difficult...
Geochemical and geophysical examination of submarine groundwater discharge and associated nutrient loading estimates into Lynch Cove, Hood Canal, WA
P.W. Swarzenski, F. W. Simonds, A.J. Paulson, S. Kruse, C. Reich
2007, Environmental Science & Technology (41) 7022-7029
Geochemical tracer data (i.e., 222Rn and four naturally occurring Ra isotopes), electromagnetic (EM) seepage meter results, and high-resolution, stationary electrical resistivity images were used to examine the bi-directional (i.e., submarine groundwater discharge and recharge) exchange of a coastal aquifer with seawater. Our study site for these experiments was Lynch Cove,...
Transport and degradation of chlorofluorocarbons (CFCs) in the pyritic Rabis Creek aquifer, Denmark
K. Hinsby, Anker L. Højberg, P. Engesgaard, K.H. Jensen, F. Larsen, Niel Plummer, Eurybiades Busenberg
2007, Water Resources Research (43)
Vertical profiles of the chlorofluorocarbons CFC‐11, CFC‐12, and CFC‐113 penetrating aerobic and anaerobic parts of a shallow sandy aquifer show that the CFC gases are degraded in the <1 m thick transition zone from aerobic to anaerobic groundwater in a pyritic sand aquifer at Rabis Creek, Denmark. Two‐dimensional solute transport...
A rangewide population genetic study of trumpeter swans
S.J. Oyler-McCance, F.A. Ransler, L.K. Berkman, T.W. Quinn
2007, Conservation Genetics (8) 1339-1353
For management purposes, the range of naturally occurring trumpeter swans (Cygnus buccinator) has been divided into two populations, the Pacific Coast Population (PP) and the Rocky Mountain Population (RMP). Little is known about the distribution of genetic variation across the species' range despite increasing pressure to make difficult management decisions...
Quantification of changes in metal loading from storm runoff, Merse River (Tuscany, Italy)
Briant A. Kimball, F. Bianchi, Katherine Walton-Day, Robert L. Runkel, M. Nannucci, A. Salvadori
2007, Mine Water and the Environment (26) 209-216
The Merse River in Tuscany is affected by mine drainage and the weathering of mine wastes along several kilometres of its catchment. The metal loading to the stream was quantified by defining detailed profiles of discharge and concentration, using tracer-dilution and synoptic-sampling techniques. During the course of a field experiment...
Adequacy of satellite derived rainfall data for stream flow modeling
G. Artan, Hussein Gadain, Jodie Smith, Kwasi Asante, C.J. Bandaragoda, J. P. Verdin
2007, Natural Hazards (43) 167-185
Floods are the most common and widespread climate-related hazard on Earth. Flood forecasting can reduce the death toll associated with floods. Satellites offer effective and economical means for calculating areal rainfall estimates in sparsely gauged regions. However, satellite-based rainfall estimates have had limited use in flood forecasting and hydrologic stream...
Random forests for classification in ecology
D.R. Cutler, T.C. Edwards Jr., K.H. Beard, A. Cutler, K.T. Hess, J. Gibson, J.J. Lawler
2007, Ecology (88) 2783-2792
Classification procedures are some of the most widely used statistical methods in ecology. Random forests (RF) is a new and powerful statistical classifier that is well established in other disciplines but is relatively unknown in ecology. Advantages of RF compared to other statistical classifiers include (1) very high classification accuracy;...
Is statistical power to detect trends a good assessment of population monitoring?
N.E. Seavy, M.H. Reynolds
2007, Biological Conservation (140) 187-191
The ability to detect trends in population abundance is of obvious interest to wildlife managers. In recent years, the probability of detecting defined population trends has been the most common method of assessing monitoring programs. Such analyses require many assumptions, including a model for population change and a model for...
Persistent chlordane concentrations in long island sound sediment: Implications from chlordane, 210Pb, and 137Cs profiles
L. Yang, X. Li, John Crusius, U. Jans, M.E. Melcer, P. Zhang
2007, Environmental Science & Technology (41) 7723-7729
Concentrations of chlordane, a banned termiticide and pesticide, were examined in recently collected surficial sediment (10 sites) and sediment cores (4 sites) in Long Island Sound (LIS).The highest chlordane concentrations were observed in western LIS, near highly urbanized areas. Chlordane concentrations did not decrease significantly in the past decade when...
Late quaternary paleoseismology of the southern Steens fault zone, northern Nevada
S. F. Personius, A. J. Crone, M. N. Machette, S. A. Mahan, J.B. Kyung, H. Cisneros, D. J. Lidke
2007, Bulletin of the Seismological Society of America (97) 1662-1678
The 192-km-long Steens fault zone is the most prominent normal fault system in the northern Basin and Range province of western North America. We use trench mapping and radiometric dating to estimate displacements and timing of the last three surface-rupturing earthquakes (E1-E3) on the southern part of the fault south...
Regional beach/cliff system dynamics along the california coast
C.J. Hapke, Don Reid
2007, Conference Paper, Coastal Sediments '07 - Proceedings of 6th International Symposium on Coastal Engineering and Science of Coastal Sediment Processes
The coast of California is comprised of both sandy shorelines and cliffed coastline, and in many areas these features spatially coincide. In order to better understand the regional trends of change along the California coast, the U.S. Geological Survey is quantifying both sandy shoreline change and coastal cliff retreat for...
Analysis of impacts of urban land use and land cover on air quality in the Las Vegas region using remote sensing information and ground observations
G. Xian
2007, International Journal of Remote Sensing (28) 5427-5445
Urban development in the Las Vegas Valley of Nevada (USA) has expanded rapidly over the past 50 years. The air quality in the valley has suffered owing to increases from anthropogenic emissions of carbon monoxide, ozone and criteria pollutants of particular matter. Air quality observations show that pollutant concentrations have...
MODIS imagery as a tool for synoptic water quality assessments in the southern California coastal ocean
N.P. Nezlin, P.M. DiGiacomo, B.H. Jones, K.M. Reifel, J.A. Warrick, S.C. Johnson, M.J. Mengel
2007, Conference Paper, Proceedings of SPIE - The International Society for Optical Engineering
The dynamics of rainstorm plumes in the coastal waters of southern California was studied during the Bight'03 Regional Water Quality Program surveys. Measurements of surface salinity and bacterial counts collected from research vessels were compared to MODIS-Aqua satellite imagery. The spectra of normalized water-leaving radiation (nLw) were different in plumes...
Aeromagnetic mapping of the structure of Pine Canyon caldera and Chisos Mountains intrusion, Big Bend National Park, Texas
B. J. Drenth, C. A. Finn
2007, Geological Society of America Bulletin (119) 1521-1534
Analysis of aeromagnetic and gravity data reveals new details of the structure, igneous geology, and temporal evolution of the prominent, enigmatic ca.32 Ma Pine Canyon caldera and the Chisos Mountains (Big Bend National Park, Texas). The main caldera-filling Pine Canyon Rhyolite, the oldest member of the South Rim Formation, is...
Evaluation of a non-point source pollution model, AnnAGNPS, in a tropical watershed
V. Polyakov, A. Fares, D. Kubo, J. Jacobi, C. Smith
2007, Environmental Modelling and Software (22) 1617-1627
Impaired water quality caused by human activity and the spread of invasive plant and animal species has been identified as a major factor of degradation of coastal ecosystems in the tropics. The main goal of this study was to evaluate the performance of AnnAGNPS (Annualized Non-Point Source Pollution Model), in...
Use of a watershed model to characterize the fate and transport of fluometuron, a soil-applied cotton herbicide, in surface water
R.H. Coupe
2007, International Journal of Environmental Analytical Chemistry (87) 883-896
The Soil and Water Assessment Tool (SWAT) was used to characterize the fate and transport of fluometuron (a herbicide used on cotton) in the Bogue Phalia Basin in northwestern Mississippi, USA. SWAT is a basin-scale watershed model, able to simulate hydrological, chemical, and sediment transport processes. After adjustments to a...
