Joint inversion of fundamental and higher mode Rayleigh waves
Y.-H. Luo, J.-H. Xia, J.-P. Liu, Q.-S. Liu
2008, Chinese Journal of Geophysics (Acta Geophysica Sinica) (51) 242-249
In this paper, we analyze the characteristics of the phase velocity of fundamental and higher mode Rayleigh waves in a six-layer earth model. The results show that fundamental mode is more sensitive to the shear velocities of shallow layers (< 7 m) and concentrated in a very narrow band (around...
Chromium, chromium isotopes and selected trace elements, western Mojave Desert, USA
J. A. Izbicki, J.W. Ball, T.D. Bullen, S. J. Sutley
2008, Applied Geochemistry (23) 1325-1352
Chromium(VI) concentrations in excess of the California Maximum Contaminant Level (MCL) of 50 μg/L occur naturally in alkaline, oxic ground-water in alluvial aquifers in the western Mojave Desert, southern California. The highest concentrations were measured in aquifers eroded from mafic rock, but Cr(VI)...
Greenland ice sheet surface temperature, melt and mass loss: 2000-06
D.K. Hall, R.S. Williams Jr., S.B. Luthcke, N.E. DiGirolamo
2008, Journal of Glaciology (54) 81-93
A daily time series of 'clear-sky' surface temperature has been compiled of the Greenland ice sheet (GIS) using 1 km resolution moderate-resolution imaging spectroradiometer (MODIS) land-surface temperature (LST) maps from 2000 to 2006. We also used mass-concentration data from the Gravity Recovery and Climate Experiment (GRACE) to study mass change...
Longitudinal gradients along a reservoir cascade
L.E. Miranda, M.D. Habrat, S. Miyazono
2008, Transactions of the American Fisheries Society (137) 1851-1865
Reservoirs have traditionally been regarded as spatially independent entities rather than as longitudinal segments of a river system that are connected upstream and downstream to the river and other reservoirs. This view has frustrated advancement in reservoir science by impeding adequate organization of available information and by hindering interchanges with...
Surface drift prediction in the Adriatic Sea using hyper-ensemble statistics on atmospheric, ocean and wave models: Uncertainties and probability distribution areas
M. Rixen, E. Ferreira-Coelho, R. Signell
2008, Journal of Marine Systems (69) 86-98
Despite numerous and regular improvements in underlying models, surface drift prediction in the ocean remains a challenging task because of our yet limited understanding of all processes involved. Hence, deterministic approaches to the problem are often limited by empirical assumptions on underlying physics. Multi-model hyper-ensemble forecasts, which exploit the power...
M-log A observations for recent large earthquakes
Thomas C. Hanks, W. H. Bakun
2008, Bulletin of the Seismological Society of America (98) 490-494
Using a magnitude (M)-log area (A) dataset augmented with seven large (M > 7.0) earthquakes occurring since Wells and Coppersmith (1994), this short note assesses the current validity of the bilinear M-log A relations for continental, strike-slip earthquakes proposed by Hanks and Bakun (2002), in particular the L-model scaling at...
Use of sinkhole and specific capacity distributions to assess vertical gradients in a karst aquifer
K.J. McCoy, M.D. Kozar
2008, Environmental Geology (54) 921-935
The carbonate-rock aquifer in the Great Valley, West Virginia, USA, was evaluated using a database of 687 sinkholes and 350 specific capacity tests to assess structural, lithologic, and topographic influences on the groundwater flow system. The enhanced permeability of the aquifer is characterized in part by the many sinkholes, springs,...
Identifying mangrove species and their surrounding land use and land cover classes using object-oriented approach with a lacunarity spatial measure
S.W. Myint, C.P. Giri, L. Wang, Z. Zhu, S.C. Gillete
2008, GIScience and Remote Sensing (45) 188-208
Accurate and reliable information on the spatial distribution of mangrove species is needed for a wide variety of applications, including sustainable management of mangrove forests, conservation and reserve planning, ecological and biogeographical studies, and invasive species management. Remotely sensed data have been used for such purposes with mixed results. Our...
A review of the endemic Hawaiian Drosophilidae and their host plants
K.N. Magnacca, D. Foote, P. M. O’Grady
2008, Zootaxa 1-58
The Hawaiian Drosophilidae is one of the best examples of rapid speciation in nature. Nearly 1,000 species of endemic drosophilids have evolved in situ in Hawaii since a single colonist arrived over 25 million years ago. A number of mechanisms, including ecological adaptation, sexual selection, and geographic isolation, have been...
Using accelerated life testing procedures to compare the relative sensitivity of rainbow trout and the federally listed threatened bull trout to three commonly used rangeland herbicides (picloram, 2,4-D, and clopyralid)
J.F. Fairchild, A. Allert, L.S. Sappington, K.J. Nelson, J. Valle
2008, Environmental Toxicology and Chemistry (27) 623-630
We conducted 96-h static acute toxicity studies to evaluate the relative sensitivity of juveniles of the threatened bull trout (Salvelinus confluentus) and the standard cold-water surrogate rainbow trout (Onchorhyncus mykiss) to three rangeland herbicides commonly used for controlling invasive weeds in the northwestern United States. Relative species sensitivity was compared...
Anatomy of the Chesapeake Bay impact structure revealed by seismic imaging, Delmarva Peninsula, Virginia, USA
R. D. Catchings, D.S. Powars, G. S. Gohn, J. Wright Horton Jr., M. R. Goldman, J.A. Hole
2008, Journal of Geophysical Research B: Solid Earth (113)
A 30-km-long, radial seismic reflection and refraction survey completed across the northern part of the late Eocene Chesapeake Bay impact structure (CBIS) on the Delmarva Peninsula, Virginia, USA, confirms that the CBIS is a complex central-peak crater. We used a tomographic P wave velocity model and low-fold reflection images, constrained...
Evaluating sampling designs by computer simulation: A case study with the Missouri bladderpod
L.W. Morrison, D. R. Smith, C. Young, D.W. Nichols
2008, Population Ecology (50) 417-425
To effectively manage rare populations, accurate monitoring data are critical. Yet many monitoring programs are initiated without careful consideration of whether chosen sampling designs will provide accurate estimates of population parameters. Obtaining accurate estimates is especially difficult when natural variability is high, or limited budgets determine that only a small...
Relative importance of natural disturbances and habitat degradation on snail kite population dynamics
J. Martin, W.M. Kitchens, Christopher E. Cattau, M.K. Oli
2008, Endangered Species Research (6) 25-39
Natural disturbances and habitat degradation are major factors influencing the dynamics and persistence of many wildlife populations, yet few large-scale studies have explored the relative influence of these factors on the dynamics and persistence of animal populations. We used longterm demographic data and matrix population models to examine the potential...
Fluctuating Arctic Sea ice thickness changes estimated by an in situ learned and empirically forced neural network model
G. I. Belchansky, David C. Douglas, Nikita G. Platonov
2008, Journal of Climate (21) 716-729
Sea ice thickness (SIT) is a key parameter of scientific interest because understanding the natural spatiotemporal variability of ice thickness is critical for improving global climate models. In this paper, changes in Arctic SIT during 1982-2003 are examined using a neural network (NN) algorithm trained with in situ submarine ice...
A prototype system for forecasting landslides in the Seattle, Washington, area
Alan F. Chleborad, Rex L. Baum, Jonathan W. Godt, Philip S. Powers
2008, Reviews in Engineering Geology (20) 103-120
Empirical rainfall thresholds and related information form the basis of a prototype system for forecasting landslides in the Seattle area. The forecasts are tied to four alert levels, and a decision tree guides the use of thresholds to determine the appropriate level. From analysis of historical landslide data, we developed...
Shallow landslide hazard map of Seattle, Washington
Edwin L. Harp, John A. Michael, William T. Laprade
2008, Reviews in Engineering Geology (20) 67-82
Landslides, particularly debris flows, have long been a significant cause of damage and destruction to people and property in the Puget Sound region. Following the years of 1996 and 1997, the Federal Emergency Management Agency designated Seattle as a “Project Impact” city with the goal of encouraging the city to...
Radiometric calibration stability and inter-calibration of solar-band instruments in orbit using the moon
T.C. Stone
2008, Conference Paper, Proceedings of SPIE - The International Society for Optical Engineering
With the increased emphasis on monitoring the Earth's climate from space, more stringent calibration requirements are being placed on the data products from remote sensing satellite instruments. Among these are stability over decade-length time scales and consistency across sensors and platforms. For radiometer instruments in the solar reflectance wavelength range...
NOAA/West Coast and Alaska Tsunami Warning Center Pacific Ocean response criteria
P. Whitmore, H. Benz, M. Bolton, G. Crawford, L. Dengler, G. Fryer, J. Goltz, R. Hansen, K. Kryzanowski, S. Malone, D. Oppenheimer, E. Petty, G. Rogers, Jim Wilson
2008, Science of Tsunami Hazards (27) 1-19
New West Coast/Alaska Tsunami Warning Center (WCATWC) response criteria for earthquakes occurring in the Pacific basin are presented. Initial warning decisions are based on earthquake location, magnitude, depth, and - dependent on magnitude - either distance from source or precomputed threat estimates generated from tsunami models. The new criteria will...
Amphipod densities and indices of wetland quality across the upper-Midwest, USA
M.J. Anteau, A. D. Afton
2008, Wetlands (28) 184-196
Nutritional, behavioral, and diet data for lesser scaup (Aythya affinis [Eyton, 1838]) indicates that there has been a decrease in amphipod (Gammarus lacustris [G. O. Sars, 1863] and Hyalella azteca [Saussure, 1858]) density and wetland quality throughout the upper-Midwest, USA. Accordingly, we estimated densities of Gammarus and Hyalella in six...
The release of dissolved actinium to the ocean: A global comparison of different end-members
W. Geibert, M. Charette, G. Kim, W.S. Moore, J. Street, M. Young, A. Paytan
2008, Marine Chemistry (109) 409-420
The measurement of short-lived 223Ra often involves a second measurement for supported activities, which represents 227Ac in the sample. Here we exploit this fact, presenting a set of 284 values on the oceanic distribution of 227Ac, which was collected when analyzing water samples for short-lived radium isotopes by the radium...
Fundamental limits to the accuracy of deuterium isotopes for identifying the spatial origin of migratory animals
A. Farmer, B.S. Cade, J. Torres-Dowdall
2008, Oecologia (158) 183-192
Deuterium isotope analyses have revolutionized the study of migratory connectivity because global gradients of deuterium in precipitation (??DP) are expressed on a continental scale. Several authors have constructed continental scale base maps of ??DP to provide a spatial reference for studying the movement patterns of migratory species and, although they...
Seabed mapping and characterization of sediment variability using the usSEABED data base
J.A. Goff, C.J. Jenkins, Williams S. Jeffress
2008, Continental Shelf Research (28) 614-633
We present a methodology for statistical analysis of randomly located marine sediment point data, and apply it to the US continental shelf portions of usSEABED mean grain size records. The usSEABED database, like many modern, large environmental datasets, is heterogeneous and interdisciplinary. We statistically test the database as a source...
ALLTEM UXO detection and discrimination
T.H. Asch, D.L. Wright, C.W. Moulton, T.P. Irons, M.N. Nabighian
2008, Conference Paper, SEG Technical Program Expanded Abstracts
ALLTEM is a multi-axis electromagnetic induction system designed for unexploded ordnance (UXO) applications. It uses a continuous triangle-wave excitation and provides good late-time signal-to-noise ratio (SNR) especially for ferrous targets. Multi-axis transmitter (Tx) and receiver (Rx) systems such as ALLTEM provide a richer data set from which to invert for...
Implications of black-tailed prairie dog spatial dynamics to black-footed ferrets
D.S. Jachowski, J.J. Millspaugh, E. Biggins, T.M. Livieri, Marc R. Matchett
2008, Natural Areas Journal (28) 14-25
The spatial dynamics of black-tailed prairie dog (Cynomys ludovicianus) colonies affect the utility of these environments for other wildlife, including the endangered black-footed ferret (Mustela nigripes). We used location data of active and inactive black-tailed prairie dog burrows to investigate colony structure, spatial distribution, and patch dynamics of two colonies...
The effects of land use on fluvial sediment chemistry for the conterminous U.S. - Results from the first cycle of the NAWQA Program: Trace and major elements, phosphorus, carbon, and sulfur
A. J. Horowitz, V. C. Stephens
2008, Science of the Total Environment (400) 290-314
In 1991, the U.S. Geological Survey (USGS) began the first cycle of its National Water Quality Assessment (NAWQA) Program. The Program encompassed 51 river basins that collectively accounted for more than 70% of the total water use (excluding power generation), and 50% of the drinking water supply in the U.S....
