Stratigraphy and palaeoclimatic significance of Late Quaternary loess-palaeosol sequences of the Last Interglacial-Glacial cycle in central Alaska
D.R. Muhs, T. A. Ager, E. Arthur Bettis III, J. McGeehin, J.M. Been, J. E. Beget, M.J. Pavich, Thomas W. Stafford Jr., D.A.S.P. Stevens
2003, Quaternary Science Reviews (22) 1947-1986
Loess is one of the most widespread subaerial deposits in Alaska and adjacent Yukon Territory and may have a history that goes back 3 Ma. Based on mineralogy and major and trace element chemistry, central Alaskan loess has a composition that is distinctive from other loess bodies of the world,...
The Mendocino crustal conveyor: Making and breaking the California crust
K.P. Furlong, J. Lock, C. Guzofski, J. Whitlock, H. Benz
2003, International Geology Review (45) 767-779
The northward migration of the Mendocino triple junction has resulted in a fundamental modification of the crust of coastal California. As a consequence of viscous coupling between the southern edge of the Gorda slab and the base of the North American crust beneath the Coast Ranges of central and northern...
Lithospheric structure, composition, and thermal regime of the East European Craton: Implications for the subsidence of the Russian platform
I.M. Artemieva
2003, Earth and Planetary Science Letters (213) 431-446
A new mechanism for Paleozoic subsidence of the Russian, or East European, platform is suggested, since a model of lithosphere tilting during the Uralian subduction does not explain the post-Uralian sedimentation record. Alternatively, I propose that the Proterozoic and Paleozoic rifting (when a platform-scale Central Russia rift system and a...
A mechanism for sustained groundwater pressure changes induced by distant earthquakes
E. E. Brodsky, E. Roeloffs, D. Woodcock, I. Gall, M. Manga
2003, Journal of Geophysical Research B: Solid Earth (108)
Large sustained well water level changes (>10 cm) in response to distant (more than hundreds of kilometers) earthquakes have proven enigmatic for over 30 years. Here we use high sampling rates at a well near Grants Pass, Oregon, to perform the first simultaneous analysis of both the dynamic response of...
An analytical formulation of two‐dimensional groundwater dispersion induced by surficial recharge variability
Eric D. Swain, David A. Chin
2003, Water Resources Research (39) 17-1-17-8
A predominant cause of dispersion in groundwater is advective mixing due to variability in seepage rates. Hydraulic conductivity variations have been extensively researched as a cause of this seepage variability. In this paper the effect of variations in surface recharge to a shallow surficial aquifer is investigated as an important...
Groundwater flow, heat transport, and water table position within volcanic edifices: Implications for volcanic processes in the Cascade Range
S. Hurwitz, K.L. Kipp, S. E. Ingebritsen, M.E. Reid
2003, Journal of Geophysical Research B: Solid Earth (108)
The position of the water table within a volcanic edifice has significant implications for volcano hazards, geothermal energy, and epithermal mineralization. We have modified the HYDROTHERM numerical simulator to allow for a free-surface (water table) upper boundary condition and a wide range of recharge rates, heat input rates, and thermodynamic...
Entropy and generalized least square methods in assessment of the regional value of streamgages
M. Markus, Knapp H. Vernon, Gary D. Tasker
2003, Journal of Hydrology (283) 107-121
The Illinois State Water Survey performed a study to assess the streamgaging network in the State of Illinois. One of the important aspects of the study was to assess the regional value of each station through an assessment of the information transfer among gaging records for low, average, and high...
Fault interactions and large complex earthquakes in the Los Angeles area
Greg Anderson, Brad T. Aagaard, Ken Hudnut
2003, Science (302) 1946-1949
Faults in complex tectonic environments interact in various ways, including triggered rupture of one fault by another, that may increase seismic hazard in the surrounding region. We model static and dynamic fault interactions between the strike-slip and thrust fault systems in southern California. We find that rupture of the Sierra...
Geology of the MER 2003 "Elysium" candidate landing site in southeastern Utopia Planitia, Mars
Kenneth L. Tanaka, Michael H. Carr, James A. Skinner, Martha S. Gilmore, Trent M. Hare
2003, Journal of Geophysical Research E: Planets (108)
The NASA Mars Exploration Rover (MER) Project has been considering a landing-site ellipse designated EP78B2 in southeastern Utopia Planitia, southwest of Elysium Mons. The site appears to be relatively safe for a MER landing site because of its predicted low wind velocities in mesoscale atmospheric circulation models and its low...
Application of two hydrologic models with different runoff mechanisms to a hillslope dominated watershed in the northeastern US: A comparison of HSPF and SMR
M.S. Johnson, W.F. Coon, V.K. Mehta, T.S. Steenhuis, E.S. Brooks, J. Boll
2003, Journal of Hydrology (284) 57-76
Differences in the simulation of hydrologic processes by watershed models directly affect the accuracy of results. Surface runoff generation can be simulated as either: (1) infiltration-excess (or Hortonian) overland flow, or (2) saturation-excess overland flow. This study compared the Hydrological Simulation Program - FORTRAN (HSPF) and the Soil Moisture Routing...
High-resolution topomapping of candidate MER landing sites with Mars Orbiter Camera narrow-angle images
Randolph L. Kirk, Elpitha Howington-Kraus, Bonnie L. Redding, Donna M. Galuszka, Trent M. Hare, Brent A. Archinal, Laurence A. Soderblom, Janet M. Barrett
2003, Journal of Geophysical Research E: Planets (108)
We analyzed narrow‐angle Mars Orbiter Camera (MOC‐NA) images to produce high‐resolution digital elevation models (DEMs) in order to provide topographic and slope information needed to assess the safety of candidate landing sites for the Mars Exploration Rovers (MER) and to assess the accuracy of our results by a variety of...
The Hula Valley subsurface structure inferred from gravity data
M. Rybakov, L. Fleischer, Uri S. ten Brink
2003, Israel Journal of Earth Sciences (52) 113-122
We use the 3-D gravity inversion technique to model the shape of the Hula basin, a pull-apart basin along the Dead Sea Transform. The interpretation was constrained using the Notera-3-well density logs and current geological knowledge. The model obtained by inversion shows a rhomb-shaped graben filled with approximately 4 km...
Source model for the Mw 6.7, 23 October 2002, Nenana Mountain earthquake (Alaska) from InSAR
Tim J. Wright, Z. Lu, Charles Wicks
2003, Geophysical Research Letters (30) 12-1-12-4
The 23 October 2002 Nenana Mountain Earthquake (Mw ∼ 6.7) occurred on the Denali Fault (Alaska), to the west of the Mw ∼ 7.9 Denali Earthquake that ruptured the same fault 11 days later. We used 6 interferograms, constructed using radar images from the Canadian Radarsat-1 and European ERS-2 satellites,...
A hydrologic network supporting spatially referenced regression modeling in the Chesapeake Bay watershed
J. W. Brakebill, S. D. Preston
2003, Environmental Monitoring and Assessment (81) 73-84
The U.S. Geological Survey has developed a methodology for statistically relating nutrient sources and land-surface characteristics to nutrient loads of streams. The methodology is referred to as SPAtially Referenced Regressions On Watershed attributes (SPARROW), and relates measured stream nutrient loads to nutrient sources using nonlinear statistical regression models. A spatially...
Characterization and statistical modeling of bacterial (Escherichia coli) outflows from watersheds that discharge into Southern Lake Michigan
G.A. Olyphant, Joan Thomas, R.L. Whitman, D. Harper
2003, Environmental Monitoring and Assessment (81) 289-300
Two watersheds in northwestern Indiana were selected for detailed monitoring of bacterially contaminated discharges (Escherichia coli) into Lake Michigan. A large watershed that drains an urbanized area with treatment plants that release raw sewage during storms discharges into Lake Michigan at the outlet of Burns Ditch. A small watershed drains...
Mercury contamination chronologies from Connecticut wetlands and Long Island Sound sediments
J.C. Varekamp, B. Kreulen, Marilyn R. Buchholtz ten Brink, E.L. Mecray
2003, Conference Paper, Environmental Geology
Sediment cores were used to investigate the mercury deposition histories of Connecticut and Long Island Sound. Most cores show background (pre-1800s) concentrations (50–100 ppb Hg) below 30–50 cm depth, strong enrichments up to 500 ppb Hg in the core tops with lower Hg concentrations in the surface sediments (200–300 ppb Hg). A sediment core...
Inversion of high frequency surface waves with fundamental and higher modes
J. Xia, R. D. Miller, C.B. Park, G. Tian
2003, Journal of Applied Geophysics (52) 45-57
The phase velocity of Rayleigh-waves of a layered earth model is a function of frequency and four groups of earth parameters: compressional (P)-wave velocity, shear (S)-wave velocity, density, and thickness of layers. For the fundamental mode of Rayleigh waves, analysis of the Jacobian matrix for high frequencies (2-40 Hz) provides...
Living with a large reduction in permited loading by using a hydrograph-controlled release scheme
P.A. Conrads, W.P. Martello, N.R. Sullins
2003, Environmental Monitoring and Assessment (81) 97-106
The Total Maximum Daily Load (TMDL) for ammonia and biochemical oxygen demand for the Pee Dee, Waccamaw, and Atlantic Intracoastal Waterway system near Myrtle Beach, South Carolina, mandated a 60-percent reduction in point-source loading. For waters with a naturally low background dissolved-oxygen concentrations, South Carolina anti-degradation rules in the water-quality...
Eruption-induced modifications to volcanic seismicity at Ruapehu, New Zealand, and its implications for eruption forecasting
C.J. Bryan, S. Sherburn
2003, Bulletin of Volcanology (65) 30-42
Broadband seismic data collected on Ruapehu volcano, New Zealand, in 1994 and 1998 show that the 1995-1996 eruptions of Ruapehu resulted in a significant change in the frequency content of tremor and volcanic earthquakes at the volcano. The pre-eruption volcanic seismicity was characterized by several independent dominant frequencies, with a...
Interpreting tracer breakthrough tailing from different forced-gradient tracer experiment configurations in fractured bedrock
M.W. Becker, A.M. Shapiro
2003, Water Resources Research (39)
Conceptual and mathematical models are presented that explain tracer breakthrough tailing in the absence of significant matrix diffusion. Model predictions are compared to field results from radially convergent, weak-dipole, and push-pull tracer experiments conducted in a saturated crystalline bedrock. The models are based upon the assumption that flow is highly...
Geoarchaeological investigations at the Winger site: A Late Paleoindian bison bonebed in Southwestern Kansas, U.S.A
R.D. Mandel, J.L. Hofman
2003, Geoarchaeology (18) 129-144
The Winger site is a deeply buried Late Paleoindian bison bonebed in a playa basin on the High Plains of midcontinental North America. The site is one of few stratified, Late Paleoindian bison kills recorded in the region. The bonebed is exposed in the bank of an intermittent stream that...
Hankin and Reeves' approach to estimating fish abundance in small streams: Limitations and alternatives
W.L. Thompson
2003, Transactions of the American Fisheries Society (132) 69-75
Hankin and Reeves' (1988) approach to estimating fish abundance in small streams has been applied in stream fish studies across North America. However, their population estimator relies on two key assumptions: (1) removal estimates are equal to the true numbers of fish, and (2) removal estimates are highly correlated with...
A proposed coast-wide reference monitoring system for evaluating Wetland restoration trajectories in Louisiana
G.D. Steyer, C.E. Sasser, J.M. Visser, E.M. Swenson, J.A. Nyman, R.C. Raynie
2003, Environmental Monitoring and Assessment (81) 107-117
Wetland restoration efforts conducted in Louisiana under the Coastal Wetlands Planning, Protection and Restoration Act require monitoring the effectiveness of individual projects as well as monitoring the cumulative effects of all projects in restoring, creating, enhancing, and protecting the coastal landscape. The effectiveness of the traditional paired-reference monitoring approach in...
Assessing the efficacy of single-pass backpack electrofishing to characterize fish community structure
M. R. Meador, J.P. McIntyre, K. H. Pollock
2003, Transactions of the American Fisheries Society (132) 39-46
Two-pass backpack electrofishing data collected as part of the U.S. Geological Survey's National Water-Quality Assessment Program were analyzed to assess the efficacy of single-pass backpack electrofishing. A two-capture removal model was used to estimate, within 10 river basins across the United States, proportional fish species richness from one-pass electrofishing and...
Methods for using groundwater model predictions to guide hydrogeologic data collection, with application to the Death Valley regional groundwater flow system
C. R. Tiedeman, M. C. Hill, F. A. D’Agnese, C.C. Faunt
2003, Water Resources Research (39)
Calibrated models of groundwater systems can provide substantial information for guiding data collection. This work considers using such models to guide hydrogeologic data collection for improving model predictions by identifying model parameters that are most important to the predictions. Identification of these important parameters can help guide collection of field...
