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...
An overview of methods for developing bioenergetic and life history models for rare and endangered species
J.H. Petersen, D.L. DeAngelis, C.P. Paukert
2008, Transactions of the American Fisheries Society (137) 244-253
Many fish species are at risk to some degree, and conservation efforts are planned or underway to preserve sensitive populations. For many imperiled species, models could serve as useful tools for researchers and managers as they seek to understand individual growth, quantify predator-prey dynamics, and identify critical sources of mortality....
Seasonal frost effects on the dynamic behavior of a twenty-story office building
Z. Yang, U. Dutta, F. Xiong, N. Biswas, H. Benz
2008, Cold Regions Science and Technology (51) 76-84
Studies have shown that seasonal frost can significantly affect the seismic behavior of a bridge foundation system in cold regions. However, little information could be found regarding seasonal frost effects on the dynamic behavior of buildings. Based on the analysis of building vibration data recorded by a permanent strong-motion instrumentation...
Role of NSO compounds during primary cracking of a Type II kerogen and a Type III lignite
F. Behar, F. Lorant, M. Lewan
2008, Organic Geochemistry (39) 1-22
The aim of this work is to follow the generation of NSO compounds during the artificial maturation of an immature Type II kerogen and a Type III lignite in order to determine the different sources of the petroleum potential during primary cracking. Experiments were carried out in closed system pyrolysis...
Recent bright gully deposits on Mars: Wet or dry flow?
Jon D. Pelletier, Kelly J. Kolb, Alfred S. McEwen, Randolph L. Kirk
2008, Geology (36) 211-214
Bright gully sediments attributed to liquid water flow have been deposited on Mars within the past several years. To test the liquid water flow hypothesis, we constructed a high-resolution (1 m/pixel) photogrammetric digital elevation model of a crater in the Centauri Montes region, where a bright gully deposit formed between...
Titan's surface from the Cassini RADAR radiometry data during SAR mode
F. Paganelli, M.A. Janssen, R.M. Lopes, E. Stofan, S. D. Wall, R. D. Lorenz, J. I. Lunine, Randolph L. Kirk, L. Roth, C. Elachi
2008, Planetary and Space Science (56) 100-108
We present initial results on the calibration and interpretation of the high-resolution radiometry data acquired during the Synthetic Aperture Radar (SAR) mode (SAR-radiometry) of the Cassini Radar Mapper during its first five flybys of Saturn's moon Titan.We construct maps of the brightness temperature at the 2-cm wavelength coincident with SAR...
Soil modification by invasive plants: Effects on native and invasive species of mixed-grass prairies
N.R. Jordan, D.L. Larson, S.C. Huerd
2008, Biological Invasions (10) 177-190
Invasive plants are capable of modifying attributes of soil to facilitate further invasion by conspecifics and other invasive species. We assessed this capability in three important plant invaders of grasslands in the Great Plains region of North America: leafy spurge (Euphorbia esula), smooth brome (Bromus inermis) and crested wheatgrass (Agropyron...
Groundwater nutrient concentrations near an incised midwestern stream: Effects of floodplain lithology and land management
K. E. Schilling, P. Jacobson
2008, Biogeochemistry (87) 199-216
It has been recognized that subsurface lithology plays an important role in controlling nutrient cycling and transport in riparian zones. In Iowa and adjacent states, the majority of alluvium preserved in small and moderate sized valleys consists of Holocene-age organic-rich, and fine-grained loam. In this paper, we describe and evaluate...
Comparisons between consumption estimates from bioenergetics simulations and field measurements for walleyes from Oneida Lake, New York
B.F. Lantry, L. G. Rudstam, J.L. Forney, A.J. VanDeValk, E.L. Mills, D.J. Stewart, J.V. Adams
2008, Transactions of the American Fisheries Society (137) 1406-1421
Daily consumption was estimated from the stomach contents of walleyes Sander vitreus collected weekly from Oneida Lake, New York, during June-October 1975, 1992, 1993, and 1994 for one to four age-groups per year. Field rations were highly variable between weeks, and trends in ration size varied both seasonally and annually....
Using demography and movement behavior to predict range expansion of the southern sea otter.
M. T. Tinker, D.F. Doak, J. A. Estes
2008, Ecological Applications (18) 1781-1794
In addition to forecasting population growth, basic demographic data combined with movement data provide a means for predicting rates of range expansion. Quantitative models of range expansion have rarely been applied to large vertebrates, although such tools could be useful for restoration and management of many threatened but recovering populations....
Numerical modeling of time-lapse monitoring of CO2 sequestration in a layered basalt reservoir
M. Khatiwada, K. Van Wijk, W.P. Clement, M. Haney
2008, Conference Paper, SEG Technical Program Expanded Abstracts
As part of preparations in plans by The Big Sky Carbon Sequestration Partnership (BSCSP) to inject CO2 in layered basalt, we numerically investigate seismic methods as a noninvasive monitoring technique. Basalt seems to have geochemical advantages as a reservoir for CO2 storage (CO2 mineralizes quite rapidly while exposed to basalt),...
Application of high-resolution linear Radon transform for Rayleigh-wave dispersive energy imaging and mode separating
Y. Luo, J. Xia, R. D. Miller, J. Liu, Y. Xu, Q. Liu
2008, Conference Paper, SEG Technical Program Expanded Abstracts
Multichannel Analysis of Surface Waves (MASW) analysis is an efficient tool to obtain the vertical shear-wave profile. One of the key steps in the MASW method is to generate an image of dispersive energy in the frequency-velocity domain, so dispersion curves can be determined by picking peaks of dispersion energy....
Aseismic slip and fault-normal strain along the central creeping section of the San Andreas fault
F. Rolandone, R. Burgmann, D.C. Agnew, I.A. Johanson, D.C. Templeton, M. A. d'Alessio, S.J. Titus, C. DeMets, B. Tikoff
2008, Geophysical Research Letters (35)
We use GPS data to measure the aseismic slip along the central San Andreas fault (CSAF) and the deformation across adjacent faults. Comparison of EDM and GPS data sets implies that, except for small-scale transients, the fault motion has been steady over the last 40 years. We add 42 new...
Hierarchical modeling of bycatch rates of sea turtles in the western North Atlantic
B. Gardner, P.J. Sullivan, S. Epperly, S.J. Morreale
2008, Endangered Species Research (5)
Previous studies indicate that the locations of the endangered loggerhead Caretta caretta and critically endangered leatherback Dermochelys coriacea sea turtles are influenced by water temperatures, and that incidental catch rates in the pelagic longline fishery vary by region. We present a Bayesian hierarchical model to examine the effects of environmental...
Characterizing an "uncharacteristics" ETS event in northern Cascadia
K. Wang, H. Dragert, H. Kao, E. Roeloffs
2008, Geophysical Research Letters (35)
GPS and borehole strainmeter data allowed the detection and model characterization of a slow slip event in northern Cascadia in November 2006 accompanying a brief episode of seismic tremor. The event is much smaller in area and duration than other well-known ETS events in northern Cascadia but is strikingly similar...
Prominent pancreatic endocrinopathy and altered control of food intake disrupt energy homeostasis in prion diseases
J. D. Bailey, J.G. Berardinelli, Tonie E. Rocke, R. A. Bessen
2008, Journal of Endocrinology (197) 251-263
Prion diseases are fatal neurodegenerative diseases that can induce endocrinopathies. The basis of altered endocrine function in prion diseases is not well understood, and the purpose of this study was to investigate the spatiotemporal relationship between energy homeostasis and prion infection in hamsters inoculated with either the 139H strain of...
Sediment dispersal in the northwestern Adriatic Sea
C. K. Harris, C. R. Sherwood, R. P. Signell, A.J. Bever, J.C. Warner
2008, Journal of Geophysical Research C: Oceans (113)
Sediment dispersal in the Adriatic Sea was evaluated using coupled three-dimensional circulation and sediment transport models, representing conditions from autumn 2002 through spring 2003. The calculations accounted for fluvial sources, resuspension by waves and currents, and suspended transport. Sediment fluxes peaked during southwestward Bora wind conditions that produced energetic waves...
Growing up green on serpentine soils: Biogeochemistry of serpentine vegetation in the Central Coast Range of California
C. Oze, C. Skinner, A.W. Schroth, R. G. Coleman
2008, Applied Geochemistry (23) 3391-3403
Serpentine soils derived from the weathering of ultramafic rocks and their metamorphic derivatives (serpentinites) are chemically prohibitive for vegetative growth. Evaluating how serpentine vegetation is able to persist under these chemical conditions is difficult to ascertain due to the numerous factors (climate, relief, time, water availability, etc.) controlling and affecting...
An annual plant growth proxy in the Mojave Desert using MODIS-EVI data
C.S.A. Wallace, K.A. Thomas
2008, Sensors (8) 7792-7808
In the arid Mojave Desert, the phenological response of vegetation is largely dependent upon the timing and amount of rainfall, and maps of annual plant cover at any one point in time can vary widely. Our study developed relative annual plant growth models as proxies for annual plant cover using...
Using sequential self-calibration method to identify conductivity distribution: Conditioning on tracer test data
B.X. Hu, C. He
2008, Mathematical Geosciences (40) 845-859
An iterative inverse method, the sequential self-calibration method, is developed for mapping spatial distribution of a hydraulic conductivity field by conditioning on nonreactive tracer breakthrough curves. A streamline-based, semi-analytical simulator is adopted to simulate solute transport in a heterogeneous aquifer. The simulation is used as the forward modeling step. In...
Erosion properties of cohesive sediments in the Colorado River in Grand Canyon
R. Akahori, M.W. Schmeeckle, D.J. Topping, T.S. Melis
2008, River Research and Applications (24) 1160-1174
Cohesive sediment deposits characterized by a high fraction of mud (silt plus clay) significantly affect the morphology and ecosystem of rivers. Potentially cohesive sediment samples were collected from deposits in the Colorado River in Marble and Grand Canyons. The erosion velocities of these samples were measured in a laboratory flume...
Quasi-periodic bedding in the sedimentary rock record of mars
Kevin W. Lewis, Oded Aharonson, John P. Grotzinger, Randolph L. Kirk, Alfred S. McEwen, Terry-Ann Suer
2008, Science (322) 1532-1535
Widespread sedimentary rocks on Mars preserve evidence of surface conditions different from the modern cold and dry environment, although it is unknown how long conditions favorable to deposition persisted. We used 1-meter stereo topographic maps to demonstrate the presence of rhythmic bedding at several outcrops in the Arabia Terra region....
Earthquake recurrence on the south Hayward fault is most consistent with a time dependent, renewal process
T. Parsons
2008, Geophysical Research Letters (35)
Elastic rebound and stress renewal are important components of earthquake forecasting because if large earthquakes can be shown to be periodic, then rupture probability is time dependent. While renewal models are used in formal forecasts, it has not been possible to exclude the alternate view that repeated large earthquakes can...
Investigation of flow and transport processes at the MADE site using ensemble Kalman filter
Gaisheng Liu, Y. Chen, Dongxiao Zhang
2008, Advances in Water Resources (31) 975-986
In this work the ensemble Kalman filter (EnKF) is applied to investigate the flow and transport processes at the macro-dispersion experiment (MADE) site in Columbus, MS. The EnKF is a sequential data assimilation approach that adjusts the unknown model parameter values based on the observed data with time. The classic...
Paleocurrent and fabric analyses of the imbricated fluvial gravel deposits in Huangshui Valley, the northeastern Tibetan Plateau, China
X. Miao, H. Lu, Z. Li, G. Cao
2008, Geomorphology (99) 433-442
Gravel deposits on fluvial terraces contain a wealth of information about the paleofluvial system. In this study, flow direction and provenance were determined by systematic counts of more than 2000 clasts of imbricated gravel deposits in the Xining Region, northeastern Tibetan Plateau, China. These gravel deposits range in age from...
