Comparison of ground motion from tremors and explosions in deep gold mines
Art McGarr, J. Bicknell, J. Churcher, S. Spottiswoode
1990, Journal of Geophysical Research Solid Earth (95) 21777-21792
Seismic body waves, from tamped chemical explosions, two with yields of 50 and one of 150 kg, were compared with corresponding data from three mining-induced tremors with a view to testing methods of discriminating between the two types of events. Detonated at depths of about 2 km, all three explosions...
The next big earthquake in the Bay Area may come sooner than you think—Are you prepared?
U.S. Geological Survey
1990, Report
Many of us breathed a little easier after October 17, 1989. The Lorna Prieta earthquake, 7.1 on the Richter scale, meant that the big one, talked about for decades, had finally happened. And, bad as it was, we had survived.There are two things wrong with that. First, Lorna Prieta was not...
Stability of giant sand waves in eastern Long Island Sound, U.S.A.
M.S. Fenster, D. M. FitzGerald, W.F. Bohlen, R. S. Lewis, C.T. Baldwin
1990, Marine Geology (91) 207-225
A combination of a highly accurate bathymetric surveying technique and in-situ submersible observations and measurements were used to assess the migrational trends and morphological changes of large sand waves (Ht ≤ 17 m) in eastern Long Island Sound. Although residing in a high-energy tidal environment characterized...
A tomographic glimpse of the upper mantle source of magmas of the Jemez lineament, New Mexico
W. Spence, R.S. Gross
1990, Journal of Geophysical Research Solid Earth (95) 10829-10849
The 800-km-long Jemez lineament is the most active volcanic feature in the southwestern United States. It is the southeastern tectonic boundary of the Colorado Plateau and crosses the Rio Grande rift at the Jemez Mountains. The primary volcanism of the lineament is basaltic and has occurred in the last 4.5...
Comparison of Darcian flow in corresponding flat and folded surfaces
Emanuel Weiss
1990, Water Resources Research (26) 1775-1785
Folds of aquifers are rarely accounted for in models of groundwater flow. To account for aquifer folds in groundwater flow models, the equation describing Darcian flow in a general surface is derived. The equation is used to calculate steady state hydraulic head distributions for corresponding folded and flat surfaces. Each...
Thermodynamics of open networks: Ordering and entropy in NaAlSiO4 glass, liquid, and polymorphs
P. Richet, R. A. Robie, J. Rogez, B. S. Hemingway, P. Courtial, C. Tequi
1990, Physics and Chemistry of Minerals (17) 385-394
The thermodynamic properties of carnegieite and NaAlSiO4 glass and liquid have been investigated through Cp determinations from 10 to 1800 K and solution-calorimetry measurements. The relative entropies S298-S0 of carnegieite and NaAlSiO4 glass are 118.7 and 124.8 J/mol K, respectively. The low-high carnegieite transition has been observed at 966 K...
Paleomagnetic rotations and the Cenozoic tectonics of the Cascade Arc, Washington, Oregon, and California
R.E. Wells
1990, Journal of Geophysical Research Solid Earth (95) 19409-19417
Paleomagnetic results from Cenozoic (62–12 Ma) volcanic rocks of the Cascade arc and adjacent areas indicate that moderate to large clockwise rotations are an important component of the tectonic history of the arc. Two mechanisms of rotation are suggested by the regional pattern of paleomagnetic rotations. The progressive increase in...
Paleoclimatic implications of the high stand of Lake Lahontan derived from models of evaporation and lake level
S. Hostetler, L. V. Benson
1990, Climate Dynamics (4) 207-217
Based on previous climate model simulations of a split of the polar jet stream during the late Pleistocene, we hypothesize that (1) 20-13.5 ka BP, season-to-season variation in the latitudinal maximum of the jet stream core led to enhanced wetness in the Great Basin, and (2) after 13.5 ka BP,...
Denitrification in sediments from the hyporheic zone adjacent to a small forested stream
J.H. Duff, F.J. Triska
1990, Canadian Journal of Fisheries and Aquatic Sciences (47) 1140-1147
Denitrifying potentials increased with increasing distance from the stream channel. Dissolved oxygen was 100% of the concentration expected in equilibrium with the atmosphere in water obtained from monitoring wells immediately adjacent to the stream but was as low as 7% of the expected value in water 11.4 m inland. Both...
Avalon terrane in eastern coastal Maine: Seismic refraction-wide-angle reflection data
J. Luetgert, C.E. Mann
1990, Geology (18) 878-881
A 145-km-long seismic refraction line recorded parallel to the eastern coastline of Maine within the Avalon terrane provides information about the crustal velocity structure within the Avalon block and its relation to other Appalachian terranes. A crustal velocity model for the upper 8...
Kilbuck terrane: Oldest known rocks in Alaska
S. E. Box, E. J. Moll-Stalcup, J. L. Wooden, J.Y. Bradshaw
1990, Geology (18) 1219-1222
The Kilbuck terrane in southwestern Alaska is a narrow, thin crustal sliver or flake of amphibolite facies orthogneiss. The igneous protolith of this gneiss was a suite of subduction-related platonic rocks. U-Pb data on zircons from trondhjemitic and granitic samples yield upper-intercept (igneous)...
Deep crustal structure of the Cascade Range and surrounding regions from seismic refraction and magnetotelluric data
William D. Stanley, Walter D. Mooney, Gary S. Fuis
1990, Journal of Geophysical Research (95) 19419-19438
Several regional seismic refraction and magnetotelluric (MT) profiles have been completed across the Cascade Range and surrounding geologic provinces in California, Oregon, and Washington. Analysis of three MT and two seismic refraction profiles in Oregon and a coincident MT and refraction profile in northern California show a high degree of...
A Miocene termite nest from southern Argentina and its paleoclimatological implications
Thomas M. Bown, Jose H. Laza
1990, Ichnos: An International Journal for Plant and Animal Traces (1) 73-79
A Miocene termitarium attributable to the extant termite Syntermes (Isoptera: Termitidae, Nasutitermitinae) is the first fossil termite nest reported from South America and possibly the oldest record of the Isoptera from that continent. The fossil remains consist of most of the periphery of the subterranean portion of a single Syntermes nest, including chambers and...
Conducting field studies for testing pesticide leaching models
Charles N. Smith, Rudolph S. Parrish, David S. Brown
1990, International Journal of Environmental Analytical Chemistry (39) 3-21
A variety of predictive models are being applied to evaluate the transport and transformation of pesticides in the environment. These include well known models such as the Pesticide Root Zone Model (PRZM), the Risk of Unsaturated-Saturated Transport and Transformation Interactions for Chemical Concentrations Model (RUSTIC) and the Groundwater Loading Effects...
Simulated effects of climatic change on runoff and drought in the Delaware River Basin
Mark A. Ayers, Gary D. Tasker, David M. Wolock, Gregory J. McCabe, Lauren E. Hay
Singh Udai P.Helweg Otto J., editor(s)
1990, Conference Paper, Supplying Water and Saving the Environment for Six Billion People
Various projection of climatic change were applied to watershed models of the Delaware River basin. Simulations indicate that a warming could reduce annual runoff by as much as 25 percent if current precipitation patterns continue. Simulations indicate that the largest changes in basin drought are in response to relatively small...
H, O, Sr, Nd, and Pb isotope geochemistry of the Latir volcanic field and cogenetic intrusions, New Mexico, and relations between evolution of a continental magmatic center and modifications of the lithosphere
C.M. Johnson, P. W. Lipman, G.K. Czamanske
1990, Contributions to Mineralogy and Petrology (104) 99-124
Over 200 H, O, Sr, Nd, and Pb isotope analyses, in addition to geologic and petrologic constraints, document the magmatic evolution of the 28.5-19 Ma Latir volcanic field and associated intrusive rocks, which includes multiple stages of crustal assimilation, magma mixing, protracted crystallization, and open- and closed-system evolution in the...
Effect of pH on the accumulation kinetics of pentachlorophenol in goldfish
G. R. Stehly, W. L. Hayton
1990, Archives of Environmental Contamination and Toxicology (19) 464-470
The kinetics of accumulation of pentachlorophenol (PCP) at various pH values were investigated to explore how pH-dependent accumulation might influence PCP toxicity. Goldfish (Carassius auratus) were exposed to 5 μg PCP/L in a static system buffered with 7.5 mM bicine orN,N-bis(2-hydroxyethyl)-2-aminoethane sulfonic acid (BES) at pH 7.0, 8.0, or 9.0....
Midcontinent rift volcanism in the Lake Superior region: Sr, Nd, and Pb isotopic evidence for a mantle plume origin
S. W. Nicholson, S.B. Shirey
1990, Journal of Geophysical Research Solid Earth (95) 10851-10868
Between 1091 and 1098 Ma, most of a 15- to 20-km thickness of dominantly tholeiitic basalt erupted in the Midcontinent Rift System of the Lake Superior region, North America. The Portage Lake Volcanics in Michigan, which are the youngest MRS flood basalts, fall into distinctly high- and low-TiO2 types having different...
Sediment movement along the U.S. east coast continental shelf-II. Modelling suspended sediment concentration and transport rate during storms
V.D. Lyne, B. Butman, W.D. Grant
1990, Continental Shelf Research (10) 429-460
Long-term near-bottom wave and current observations and a one-dimensional sediment transport model are used to calculate the concentration and transport of sediment during winter storms at 60-80 m water depth along the southern flank of Georges Bank and in the Mid-Atlantic Bight. Calculations are presented for five stations, separated by...
A new planktic foraminifer transfer function for estimating pliocene-Holocene paleoceanographic conditions in the North Atlantic
H.J. Dowsett, R.Z. Poore
1990, Marine Micropaleontology (16) 1-23
A new planktic foraminifer transfer function (GSF18) related 5 North Atlantic assemblages to winter and summer sea surface temperature. GSF18, based on recombined and simplified core top census data, preserves most environmental information and reproduces modern North Atlantic conditions with approximately the same accuracy as previous transfer functions, but can...
A study of model bivalve siphonal currents
Stephen G. Monismith, Jeffrey R. Koseff, Janet K. Thompson, Catherine A. O’Riordan, Heidi M. Nepf
1990, Limnology and Oceanography (35) 680-696
We carried out experiments studying the hydrodynamics of bivalve siphonal currents in a laboratory flume. Rather than use living animals, we devised a simple, model siphon pair connected to a pump. Fluorescence-based flow visualization was used to characterize siphon-jet flows for several geometric configurations and flow speeds. These measurements show...
Equivalent strike-slip earthquake cycles in half-space and lithosphere-asthenosphere earth models
J.C. Savage
1990, Journal of Geophysical Research (95) 4873-4879
By virtue of the images used in the dislocation solution, the deformation at the free surface produced throughout the earthquake cycle by slippage on a long strike-slip fault in an Earth model consisting of an elastic plate (lithosphere) overlying a viscoelastic half-space (asthenosphere) can be duplicated by prescribed slip on...
Kinetically influenced terms for solute transport affected by heterogeneous and homogeneous classical reactions
Jean M. Bahr
1990, Water Resources Research (26) 21-34
Simulation of transport affected by heterogeneous or homogeneous reversible reactions requires a choice between local equilibrium-based and kinetics-based models. The error associated with the use of equilibrium-based models is equivalent to the error of neglecting certain mathematical terms in the governing kinetics-based transport equations. Identification and evaluation of these kinetically...
Instantaneous and daily values of the surface energy balance over agricultural fields using remote sensing and a reference field in an arid environment
William P. Kustas, M. S. Moran, R. D. Jackson, L. W. Gay, L.F.W. Duell, K. E. Kunkel, A.D. Matthias
1990, Remote Sensing of Environment (32) 125-141
Remotely sensed surface temperature and reflectance in the visible and near infrared wavebands along with ancilliary meteorological data provide the capability of computing three of the four surface energy balance components (i.e., net radiation, soil heat flux, and sensible heat flux) at different spatial and temporal scales. As a result,...
The Stillwater Complex and its anorthosites: an accident of magmatic underplating?
G.K. Czamanske, S.R. Bohlen
1990, American Mineralogist (75) 37-45
The Stillwater Complex, emplaced 2700??40 Ma, is exposed at the edge of a 4000-km2 block of Late Archean rocks that formed 40 to 110 m.y. yearlier. Voluminous plagioclase cumulates (anorthosites) within the Middle Banded series of the complex are difficult to explain either by in situ fractionation of mafic magma...
