Solving the dynamic rupture problem with different numerical approaches and constitutive laws
A. Bizzarri, M. Cocco, D.J. Andrews, Enzo Boschi
2001, Geophysical Journal International (144) 656-678
We study the dynamic initiation, propagation and arrest of a 2-D in-plane shear rupture by solving the elastodynamic equation by using both a boundary integral equation method and a finite difference approach. For both methods we adopt different constitutive laws: a slip-weakening (SW) law, with constant weakening rate, and rate-...
Enantiomeric composition of chiral polychlorinated biphenyl atropisomers in aquatic and riparian biota
C.S. Wong, A.W. Garrison, P.D. Smith, W.T. Foreman
2001, Environmental Science & Technology (35) 2448-2454
The enantiomeric composition of polychlorinated biphenyl (PCB) atropisomers was measured in river and riparian biota (fish, bivalves, crayfish, water snakes, barn swallows) from selected sites throughout the United States by using chiral gas chromatography/mass spectrometry. Nonracemic enantiomeric fractions (EFs) were observed for PCBs 91, 95, 136, and 149 for aquatic...
Crustal displacements due to continental water loading
T. Van Dam, J. Wahr, P. C. D. Milly, A.B. Shmakin, G. Blewitt, D. Lavallee, K.M. Larson
2001, Geophysical Research Letters (28) 651-654
The effects of long-wavelength (> 100 km), seasonal variability in continental water storage on vertical crustal motions are assessed. The modeled vertical displacements (??rM) have root-mean-square (RMS) values for 1994-1998 as large as 8 mm, with ranges up to 30 mm, and are predominantly annual in character. Regional strains are...
Mineralogy of the last lunar basalts: Results from Clementine
M.I. Staid, C.M. Pieters
2001, Journal of Geophysical Research E: Planets (106) 27887-27900
The last major phase of lunar volcanism produced extensive high-titanium mare deposits on the western nearside which remain unsampled by landing missions. The visible and near-infrared reflectance properties of these basalts are examined using Clementine multispectral images to better constrain their mineralogy. A much stronger 1 μm ferrous absorption was...
Catchment-scale variation in the nitrate concentrations of groundwater seeps in the Catskill Mountains, New York, U.S.A.
A.J. West, S.E.G. Findlay, Douglas A. Burns, K.C. Weathers, Gary M. Lovett
2001, Water, Air, & Soil Pollution (132) 389-400
Forested headwater streams in the Catskill Mountains of New York show significant among-catchment variability in mean annual nitrate (NO3-) concentrations. Large contributions from deep groundwater with high NO3- concentrations have been invoked to explain high NO3- concentrations in stream water during the growing season. To determine whether variable contributions of...
Aerogeophysical measurements of collapse-prone hydrothermally altered zones at Mount Rainier volcano
C. A. Finn, T. W. Sisson, M. Deszcz-Pan
2001, Nature (409) 600-603
Hydrothermally altered rocks can weaken volcanoes, increasing the potential for catastrophic sector collapses that can lead to destructive debris flows1. Evaluating the hazards associated with such alteration is difficult because alteration has been mapped on few active volcanoes1-4 and the distribution and severity of subsurface alteration is largely unknown on...
Selection of habitats by Emperor Geese during brood rearing
Joel A. Schmutz
2001, Waterbirds (24) 394-401
Although forage quality strongly affects gosling growth and consequently juvenile survival, the relative use of different plant communities by brood rearing geese has been poorly studied. On the Yukon-Kuskokwim Delta, Alaska, population growth and juvenile recruitment of Emperor Geese (Chen canagica) are comparatively low, and it is unknown whether their...
Effects of acidic recharge on groundwater at the St. Kevin Gulch site, Leadville, Colorado
S.S. Paschke, W.J. Harrison, K. Walton-Day
2001, Geochemistry: Exploration, Environment, Analysis (1) 3-14
The acid rock drainage-affected stream of St. Kevin Gulch recharges the Quaternary sand and gravel aquifer of Tennessee Park, near Leadville, Colorado, lowering pH and contributing iron, cadmium, copper, zinc and sulphate to the ground-water system. Dissolved metal mobility is controlled by the seasonal spring runoff as well as oxidation/reduction...
Habitat fragmentation effects on birds in grasslands and wetlands: A critique of our knowledge
Douglas H. Johnson
2001, Great Plains Research (11) 211-231
Habitat fragmentation exacerbates the problem of habitat loss for grassland and wetland birds. Remaining patches of grasslands and wetlands may be too small, too isolated, and too influenced by edge effects to maintain viable populations of some breeding birds. Knowledge of the effects of fragmentation on bird populations is critically...
On the rarity of observations of food provisioning by male dickcissels
L.D. Igl, Louis B. Best
2001, Prairie Naturalist (33) 111-118
Males of polygynous bird species typically provide less parental care to their offspring than males of monogamous species (Ketterson and Nolan 1994). Generally, in polygynous species, a male forfeits some potential reproductive success if he shifts his reproductive effort from mating with multiple females to parental care (Trivers 1972, Gubemick...
New views of granular mass flows
R.M. Iverson, J.W. Vallance
2001, Geology (29) 115-118
Concentrated grain-fluid mixtures in rock avalanches, debris flows, and pyroclastic flows do not behave as simple materials with fixed rheologies. Instead, rheology evolves as mixture agitation, grain concentration, and fluid-pressure change during flow initiation, transit, and deposition. Throughout a flow, however, normal forces on planes parallel to the free upper...
Use of macroinvertebrates to identify cultivated wetlands in the Prairie Pothole Region
Ned H. Euliss Jr., David M. Mushet, Douglas H. Johnson
2001, Wetlands (21) 223-231
We evaluated the use of macroinvertebrates as a potential tool to identify dry and intensively farmed temporary and seasonal wetlands in the Prairie Pothole Region. The techniques we designed and evaluated used the dried remains of invertebrates or their egg banks in soils as indicators of wetlands. For both the...
Description and evaluation of a remote camera and triggering system to monitor carnivores
E.C. York, T.L. Moruzzi, T.K. Fuller, J.F. Organ, R.M. Sauvajot, R.M. DeGraaf
2001, Wildlife Society Bulletin (29) 1228-1237
Remotely triggered cameras have been used in many ecological studies, but most are relatively inexpensive one-time-only systems or expensive infrared systems. We describe the setup and wiring technique for a moderately priced, multiple-photo camera system. Two study areas, California and Vermont, were used to assess usefulness of the camera system....
Sediment quality in Burlington Harbor, Lake Champlain, U.S.A.
E.M. Lacey, J.W. King, J.G. Quinn, E.L. Mecray, P.G. Appleby, A.S. Hunt
2001, Water, Air, & Soil Pollution (126) 97-120
Surface samples and cores were collected in 1993 from the Burlington Harbor region of Lake Champlain. Sediment samples were analyzed for trace metals (cadmium, copper, lead, nickel, silver and zinc), simultaneously extracted metal/acid volatile sulfide (SEM-AVS), grain size, nutrients (carbon and nitrogen) and organic contaminants (polycyclic aromatic hydrocarbons (PAHs) and...
Occurrence and Diversity of Tetracycline Resistance Genes in Lagoons and Groundwater Underlying Two Swine Production Facilities
J. C. Chee-Sanford, R.I. Aminov, I.J. Krapac, N. Garrigues-Jeanjean, R.I. Mackie
2001, Applied and Environmental Microbiology (67) 1494-1502
In this study, we used PCR typing methods to assess the presence of tetracycline resistance determinants conferring ribosomal protection in waste lagoons and in groundwater underlying two swine farms. All eight classes of genes encoding this mechanism of resistance [tet(O), tet(Q), tet(W), tet(M), tetB(P), tet(S), tet(T), and otrA] were found...
Demonstration and Field Evaluation of Streambank Stabilization with Submerged Vanes
H. Whitman, J. Hoopes, D. Poggi, F. Fitzpatrick, K. Walz
Hayes D.F.Hayes D.F., editor(s)
2001, Conference Paper, Proceedings of the 2001 Wetlands Engineering and River Restoration Conference
The effectiveness of submerged vanes for reducing bank erosion and improving aquatic habitat is being evaluated at a site on North Fish Creek, a Lake Superior tributary. Increased runoff from agricultural areas with clayey soils has increased flood magnitudes and the erosion potential/transport capacity of the stream. Most of the...
Improving the quality of mass produced maps
Jeffrey D. Simley
2001, Cartography and Geographic Information Science (28) 97-110
Quality is critical in cartography because key decisions are often made based on the information the map communicates. The mass production of digital cartographic information to support geographic information science has now added a new dimension to the problem of cartographic quality, as problems once limited to small volumes can...
Melt-inclusion-hosted excess 40Ar in quartz crystals of the Bishop and Bandelier magma systems
J. A. Winick, W. C. McIntosh, N. W. Dunbar
2001, Geology (29) 275-278
40Ar/39Ar experiments on melt-inclusion–bearing quartz (MIBQ) from the Bishop and Bandelier Tuff Plinian deposits indicate high concentrations of excess 40Ar in melt inclusions. Two rhyolite glass melt inclusion populations are present in quartz; exposed melt inclusions and trapped melt inclusions. Air-abrasion mill grinding and hydrofluoric acid treatments progressively remove exposed melt...
Wisconsin Glaciation of the Sierra Nevada (79,000-15,000 yr B.P.) as recorded by rock flour in sediments of Owens Lake, California
J. L. Bischoff, K. Cummins
2001, Quaternary Research (55) 14-24
Chemical analyses of the clay-sized fractions of 564 continuous sediment samples (200-yr resolution) from composite core OL90/92 allow quantification of an abundance of glacial rock flour. Rock flour produced during glacier advances is represented by clay-sized plagioclase, K-feldspar, and biotite in homogeneous internal composition. The abundance of rock flour is...
The Precambrian terranes of Yemen and their correlation with those of Saudi Arabia and Somalia: Implications for the accretion of Gondwana
B.F. Windley, M.J. Whitehouse, D. B. Stoeser, S. Al-Khirbash, M. A. O. Ba-Bttat, A. Al-Ghotbah
2001, Gondwana Research (4) 206-207
Most of the basement of Yemen consists of early Precambrian continental high-grade terranes and Neoproterozoic low-grade island arcs that were accreted together to form an arc-continent collage during the Pan-African orogeny (Windley et al., 1996; Whitehouse et al., 1998; Whitehouse et al., in press)....
Myrmecophagy by Yellowstone grizzly bears
David J. Mattson
2001, Canadian Journal of Zoology (79) 779-793
I used data collected during a study of radio-marked grizzly bears (Ursus arctos horribilis) in the Yellowstone region from 1977 to 1992 to investigate myrmecophagy by this population. Although generally not an important source of energy for the bears (averaging <5% of fecal volume at peak consumption), ants may have...
Stepped-combustion 14C dating of sediment: A comparison with established techniques
J. McGeehin, G. S. Burr, A.J.T. Juli, D. Reines, J. Gosse, P.T. Davis, D. Muhs, J. R. Southon
2001, Radiocarbon (43) 255-261
Radiocarbon dating of bulk sediment has long been used as a method of last resort when reliable wood, charcoal, or plant macrofossils are not available for analysis. Accurate dating of sediment is complicated by the presence of multiple organic carbon fractions, each with a potentially different 14C activity. Additionally, the...
Early post-fire succession in California chaparral: Changes in diversity, density, cover and biomass
Q. Guo
2001, Ecological Research (16) 471-485
For four consecutive years, following the fires in November 1993, temporal variations in species richness, cover and biomass of component plant groups in early post-fire chaparral succession were monitored on different aspects at the Stunt Ranch Santa Monica Mountains Reserve, southern California. Plant groups were categorized based on growth form,...
Aircraft and runway deicers at General Mitchell International Airport, Milwaukee, Wisconsin, USA. 1. Biochemical oxygen demand and dissolved oxygen in receiving streams
S.R. Corsi, N.L. Booth, D. W. Hall
2001, Environmental Toxicology and Chemistry (20) 1474-1482
Aircraft and runway deicers are used during cold weather at many of the world's airports to facilitate safe air travel. Propylene glycol-, ethylene glycol-, and urea-based deicers are known to have very high biochemical oxygen demand. At General Mitchell International Airport (GMIA) in Milwaukee, Wisconsin, USA, deicer application, water chemistry,...
Slip distribution and tectonic implication of the 1999 Chi-Chi, Taiwan, earthquake
C. Ji, D.V. Helmberger, T.-R.A. Song, K.-F. Ma, D.J. Wald
2001, Geophysical Research Letters (28) 4379-4382
We report on the fault complexity of the large (Mw = 7.6) Chi-Chi earthquake obtained by inverting densely and well-distributed static measurements consisting of 119 GPS and 23 doubly integrated strong motion records. We show that the slip of the Chi-Chi earthquake was concentrated on the surface of a "wedge...
