A Viscoelastic earthquake simulator with application to the San Francisco Bay region
Fred F. Pollitz
2009, Bulletin of the Seismological Society of America (99) 1760-1785
Earthquake simulation on synthetic fault networks carries great potential for characterizing the statistical patterns of earthquake occurrence. I present an earthquake simulator based on elastic dislocation theory. It accounts for the effects of interseismic tectonic loading, static stress steps at the time of earthquakes, and postearthquake stress readjustment through viscoelastic...
Water balance dynamics in the Nile Basin
Gabriel B. Senay, Kwabena Asante, Guleid A. Artan
2009, Hydrological Processes (23) 3675-3681
Understanding the temporal and spatial dynamics of key water balance components of the Nile River will provide important information for the management of its water resources. This study used satellite-derived rainfall and other key weather variables derived from the Global Data Assimilation System to estimate and map the distribution of...
Isotopic composition of low-latitude paleoprecipitation during the Early Cretaceous
M.B. Suarez, Luis A. Gonzalez, Greg A. Ludvigson, F.J. Vega, J. Alvarado-Ortega
2009, Geological Society of America Bulletin (121) 1584-1595
The response of the hydrologic cycle in global greenhouse conditions is important to our understanding of future climate change and to the calibration of global climate models. Past greenhouse conditions, such as those of the Cretaceous, can be used to provide empirical data with which to evaluate climate models. Recent...
First-order exchange coefficient coupling for simulating surface water-groundwater interactions: Parameter sensitivity and consistency with a physics-based approach
B.A. Ebel, B.B. Mirus, C.S. Heppner, J.E. VanderKwaak, K. Loague
2009, Hydrological Processes (23) 1949-1959
Distributed hydrologic models capable of simulating fully-coupled surface water and groundwater flow are increasingly used to examine problems in the hydrologic sciences. Several techniques are currently available to couple the surface and subsurface; the two most frequently employed approaches are first-order exchange coefficients (a.k.a., the surface conductance method) and enforced...
Comparing approaches for simulating the reactive transport of U(VI) in ground water
G.P. Curtis, M. Kohler, J.A. Davis
2009, Mine Water and the Environment (28) 84-93
The reactive transport of U(VI) in a well-characterized shallow alluvial aquifer at a former U(VI) mill located near Naturita, CO, was predicted for comparative purposes using a surface complexation model (SCM) and a constant K d approach to simulate U(VI) adsorption. The ground water at the site had U(VI) concentrations that...
SBAS-InSAR analysis of surface deformation at Mauna Loa and Kilauea volcanoes in Hawaii
F. Casu, Riccardo Lanari, E. Sansosti, G. Solaro, Pietro Tizzani, Michael Poland, Asta Mikijus
2009, Conference Paper, International Geoscience and Remote Sensing Symposium (IGARSS)
We investigate the deformation of Mauna Loa and Kllauea volcanoes, Hawai'i, by exploiting the advanced differential Synthetic Aperture Radar Interferometry (InSAR) technique referred to as the Small BAseline Subset (SBAS) algorithm. In particular, we present time series of line-of-sight (LOS) displacements derived from SAR data acquired by the ASAR instrument,...
Pore-water chemistry from the ICDP-USGS core hole in the Chesapeake Bay impact structure-Implications for paleohydrology, microbial habitat, and water resources
W. E. Sanford, M.A. Voytek, D.S. Powars, B.F. Jones, I.M. Cozzarelli, C.S. Cockell, R.P. Eganhouse
2009, Special Paper of the Geological Society of America 867-890
We investigated the groundwater system of the Chesapeake Bay impact structure by analyzing the pore-water chemistry in cores taken from a 1766-m-deep drill hole 10 km north of Cape Charles, Virginia. Pore water was extracted using high-speed centrifuges from over 100 cores sampled from a 1300 m section of the...
Assessing spatial uncertainty in reservoir characterization for carbon sequestration planning using public well-log data: A case study
E.R. Venteris, K.M. Carter
2009, Environmental Geosciences (16) 211-234
Mapping and characterization of potential geologic reservoirs are key components in planning carbon dioxide (CO2) injection projects. The geometry of target and confining layers is vital to ensure that the injected CO2 remains in a supercritical state and is confined to the target layer. Also, maps of injection volume (porosity)...
Geologic columns for the ICDP-USGS Eyreville A and C cores, Chesapeake Bay impact structure: Postimpact sediments, 444 to 0 m depth
Lucy E. Edwards, David S. Powars, J.V. Browning, P.P. McLaughlin Jr., K.G. Miller, Self-Trail J.M., A.A. Kulpecz, T. Elbra
2009, Special Paper of the Geological Society of America 91-114
A 443.9-m-thick, virtually undisturbed section of postimpact deposits in the Chesapeake Bay impact structure was recovered in the Eyreville A and C cores, Northampton County, Virginia, within the "moat" of the structure's central crater. Recovered sediments are mainly fine-grained marine siliciclastics, with the exception of Pleistocene sand, clay, and gravel....
Geology and geomorphology of Bear Lake Valley and upper Bear River, Utah and Idaho
M.C. Reheis, B.J.C. Laabs, D. S. Kaufman
2009, Special Paper of the Geological Society of America 15-48
Bear Lake, on the Idaho-Utah border, lies in a fault-bounded valley through which the Bear River flows en route to the Great Salt Lake. Surficial deposits in the Bear Lake drainage basin provide a geologic context for interpretation of cores from Bear Lake deposits. In addition to groundwater discharge, Bear...
Recent status and trends of the land bird avifauna on Saipan, Mariana Islands, with emphasis on the endangered Nightingale Reed-warbler Acrocephalus luscinia
R.J. Camp, T.K. Pratt, A.P. Marshall, F. Amidon, L.L. Williams
2009, Bird Conservation International (19) 323-337
The avifauna of the Mariana Islands, an archipelago in the western Pacific, faces the threats of rapid economic development and the spread of non-native species, particularly a devastating predator, Brown Tree Snake Boiga irregularis. In this paper, we examine the status and trends of the land bird fauna of Saipan...
Hurricane Rita and the destruction of Holly Beach, Louisiana: Why the chenier plain is vulnerable to storms
Asbury H. Sallenger Jr., C. W. Wright, Kara Doran, K. Guy, Karen Morgan
2009, Special Paper of the Geological Society of America (460) 127-135
Hurricane Rita devastated gulf-front communities along the western Louisiana coast in 2005. LIDAR (light detection and ranging) topographic surveys and aerial photography collected before and after the storm showed the loss of every structure within the community of Holly Beach. Average shoreline change along western Louisiana's 140-km-long impacted shore was...
Gravity investigations of the Chesapeake Bay impact structure
J. B. Plescia, D. L. Daniels, A. K. Shah
2009, Special Paper of the Geological Society of America 181-193
The Chesapeake Bay impact structure is a complex impact crater, ??85 km in diameter, buried beneath postimpact sediments. Its main structural elements include a central uplift of crystalline bedrock, a surrounding inner crater filled with impact debris, and an annular faulted margin composed of block-faulted sediments. The gravity anomaly is...
Rapid measurement of field-saturated hydraulic conductivity for areal characterization
J. R. Nimmo, K. M. Schmidt, K. S. Perkins, J. D. Stock
2009, Vadose Zone Journal (8) 142-149
To provide an improved methodology for characterizing the field‐saturated hydraulic conductivity (Kfs) over broad areas with extreme spatial variability and ordinary limitations of time and resources, we developed and tested a simplified apparatus and procedure, correcting mathematically for the major deficiencies of the simplified implementation. The methodology includes use of...
Trends in concentrations and use of agricultural herbicides for Corn Belt rivers, 1996-2006
Aldo V. Vecchia, Robert J. Gilliom, Daniel J. Sullivan, David L. Lorenz, Jeffrey D. Martin
2009, Environmental Science & Technology (43) 9096-9102
Trends in the concentrations and agricultural use of four herbicides (atrazine, acetochlor, metolachlor, and alachlor) were evaluated for major rivers of the Corn Belt for two partially overlapping time periods: 1996-2002 and 2000-2006. Trends were analyzed for 11 sites on the mainstems and selected tributaries in the Ohio, Upper Mississippi,...
Persistence of effects of high sediment loading in a salmon-bearing river, northern California
Mary Ann Madej, V. Ozaki
2009, Special Paper of the Geological Society of America 43-55
Regional high-magnitude rainstorms have produced several large floods in north coastal California during the last century, which resulted in extensive massmovement activity and channel aggradation. Channel monitoring in Redwood Creek, through the use of cross-sectional surveys, thalweg profi les, and pebble counts, has documented the persistence and routing of channel-stored...
On baseline corrections and uncertainty in response spectrafor baseline variations commonly encountered in digital accelerograph records
Sinan Akkar, David M. Boore
2009, Bulletin of the Seismological Society of America (99) 1671-1690
Most digital accelerograph recordings are plagued by long-period drifts, best seen in the velocity and displacement time series obtained from integration of the acceleration time series. These drifts often result in velocity values that are nonzero near the end of the record. This is clearly unphysical and can lead to...
Surface complexation modeling of U(VI) adsorption by aquifer sediments from a former mill tailings site at Rifle, Colorado
S.P. Hyun, P.M. Fox, J.A. Davis, K.M. Campbell, K.F. Hayes, P.E. Long
2009, Environmental Science & Technology (43) 9368-9373
A study of U(VI) adsorption by aquifer sediment samples from a former uranium mill tailings site at Rifle, Colorado, was conducted under oxic conditions as a function of pH, U(VI), Ca, and dissolved carbonate concentration. Batch adsorption experiments were performed using <2mm size sediment fractions, a sand-sized fraction, and artificial...
Non-double-couple mechanisms of microearthquakes induced by hydraulic fracturing
J. Sileny, D.P. Hill, Leo Eisner, F.H. Cornet
2009, Journal of Geophysical Research B: Solid Earth (114)
We have inverted polarity and amplitude information of representative microearthquakes to investigate source mechanisms of seismicity induced by hydraulic fracturing in the Carthage Cotton Valley, east Texas, gas field. With vertical arrays of four and eight three-component geophones in two monitoring wells, respectively, we were able to reliably determine source...
Simulating and understanding sand wave variation: A case study of the Golden Gate sand waves
F. Sterlini, S.J.M.H. Hulscher, D.M. Hanes
2009, Journal of Geophysical Research F: Earth Surface (114)
In this paper we present a detailed comparison between measured features of the Golden Gate sand wave field and the results of a nonlinear sand wave model. Because the Golden Gate sand waves exhibit large variation in their characteristics and in their environmental physics, this area gives us the opportunity...
Ecology and the ratchet of events: Climate variability, niche dimensions, and species distributions
S.T. Jackson, J.L. Betancourt, R.K. Booth, S.T. Gray
2009, Conference Paper, Proceedings of the National Academy of Sciences of the United States of America
Climate change in the coming centuries will be characterized by interannual, decadal, and multidecadal fluctuations superimposed on anthropogenic trends. Predicting ecological and biogeographic responses to these changes constitutes an immense challenge for ecologists. Perspectives from climatic and ecological history indicate that responses will be laden with contingencies, resulting from episodic...
Allogenic sedimentary components of Bear Lake, Utah and Idaho
J. G. Rosenbaum, W.E. Dean, R. L. Reynolds, M.C. Reheis
2009, Special Paper of the Geological Society of America 145-168
Bear Lake is a long-lived lake filling a tectonic depression between the Bear River Range to the west and the Bear River Plateau to the east, and straddling the border between Utah and Idaho. Mineralogy, elemental geochemistry, and magnetic properties provide information about variations in provenance of allogenic lithic material...
Scaling the effects of moose browsing on forage distribution, from the geometry of plant canopies to landscapes
N. R. De Jager, J. Pastor, A.L. Hodgson
2009, Ecological Monographs (79) 281-297
Landscape heterogeneity influences large herbivores by altering their feeding rates, but as herbivores attempt to maximize feeding rates they also create spatial heterogeneity by altering plant growth. Herbivore feeding rates thus provide a quantitative link between the causes and consequences of spatial heterogeneity in herbivore-dominated ecosystems. The fractal geometry of...
Effects of rodent community diversity and composition on prevalence of an endemic bacterial pathogen - Bartonella
Y. Bai, M.Y. Kosoy, C.H. Calisher, J.F. Cully Jr., S.K. Collinge
2009, Biodiversity (10) 3-11
By studying Bartonella prevalence in rodent communities from 23 geographic sites in the western United States and one site in northern Mexico, the present study focused on the effects of rodent community diversity (measured by richness and Shannon index) and composition on prevalence of Bartonella infections. The analysis showed negative correlations of Bartonella prevalence with rodent...
Northern Monterey Bay upwelling shadow front: Observations of a coastally and surface-trapped buoyant plume
C.B. Woodson, L. Washburn, J.A. Barth, D.J. Hoover, A.R. Kirincich, M.A. McManus, J.P. Ryan, J. Tyburczy
2009, Journal of Geophysical Research C: Oceans (114)
During the upwelling season in central California, northwesterly winds along the coast produce a strong upwelling jet that originates at Point A??o Nuevo and flows southward across the mouth of Monterey Bay. A convergent front with a mean temperature change of 3.77 ?? 0.29??C develops between the warm interior waters...
